WO2024153516A1

WO2024153516A1 - Fiber optic fan-out assembly

Info

Publication number: WO2024153516A1
Application number: PCT/EP2024/050476
Authority: WO
Inventors: Daniel Greub; Nando KRETZ; Pascal REUTIMANN; Samuel STAEHLI
Original assignee: Huber+Suhner Ag
Priority date: 2023-01-17
Filing date: 2024-01-10
Publication date: 2024-07-25

Abstract

The present disclosure relates to a fiber optic fan-out assembly (1) comprising, a cable arrangement (2) which comprises a trunk cable (3) comprising optic fibers (4) in form of a bundle and/or at least one ribbon, preferably encompassed by a trunk cable sheathing (5) and a number of pigtails (6) arranged opposite to the trunk cable (3) with respect to a housing (7). The housing (7) extends in an axial direction (x) and encompasses in the axial direction (x) a first cable passage (8) through which the optic fibers (4) of the trunk cable (3) enter the housing (7), a transition space (9) through which the optic fibers (4) extend in the axial direction (x) and which acts as an integrated splice protector, a deflection space (10) in which the optic fibers (4) are deflected forming at least one hump (11) extending in a lateral direction (y, z) and a second cable passage (12) through which the optic fibers (4) exit the housing (7) into the pigtails (6).

Description

Fiber optic fan-out assembly

FIELD OF THE DISCLOSURE

The present disclosure relates to a fiber optic fan-out assembly for optic fibers and a method for assembling the fiber optic fan-out assembly.

BACKGROUND OF THE DISCLOSURE

US2022026658A1 published on 27.01.2022 on behalf of Corning Res. and Dev. Corp., relates to a method of furcating a fiber optic cable. The method includes positioning an inlet fan-out tube and a furcation housing spaced from an end of the cable, removing a protective jacket from the cable to define an exposed portion of a plurality of cable optic fibers, providing a plurality of pre-manufactured connector assemblies that each have an optic connector, splicing the cable optic fibers to a respective one of the connector assemblies to define a splicing region and repositioning the furcation housing and the inlet fan-out tube so that the splicing region is positioned within the furcation housing and the inlet fan-out tube covers a section of the exposed portion of the plurality of cable optic fibers. Fiber optic cable assemblies formed by the method are also disclosed.

US2020301074A2 published on 24.09.2020 on behalf of Commscope Technologies LLC relates to fusion spliced cable assemblies. An assembly may include a first and a second fiber optic cable, where an end of at least a first optical fiber from the first fiber optic cable is fusion spliced together with an end of at least a second optical fiber from the second fiber optic cable. The first optical fiber having a first length of prepared fiber extending from the spliced end of the first optical fiber to a transition point of the first optical fiber. The second optical fiber having a second length of prepared fiber extending from the spliced end of the second optical fiber to a transition point of the second optical fiber. The transition point of the first optical fiber is a distance from the transition point of the second optical fiber. A total length of prepared fiber is the sum of the first length of prepared fiber for the first optical fiber and the second length of prepared fiber for the second optical fiber. A support configured to engage at least a portion of the total length of prepared fiber such that the distance between the transition points of each optical fiber is less than the total length of prepared fiber of the first and second optical fibers. A transition housing coupled to the first and second fiber optic cables and surrounding the support. Fusion spliced cable assembly breakout kits are also provided.

US2020103609A1 published on behalf of Commscope Technologies LLC on 02.04.2020, relates to a breakout transition assembly including a plurality of optic fibers extending through a cable, a plurality of furcation tubes and a housing with a cable inlet and a furcation chamber. The cable, optic fibers and furcation tubes are fixed relative to the housing with a volume of hardened epoxy in the furcation chamber. The cable inlet includes a clearance that tapers between a first end and a second end. In another aspect, the breakout transition can also include a breakout holder comprising at least one guide, such that he plurality of furcation tubes are fixedly received in the at least one guide in the breakout holder, and the volume of hardened epoxy retains the breakout holder in an engaged position with the transition body. US2020081218A1 published on behalf of Corning Inc. on 12.03.2020, relates to an optic fiber optic fan-out assembly, which includes multiple optic fibers arranged in a one-dimensional array in a transition segment in which spacing between fibers is varied from a first pitch to a second pitch. A polymeric material encapsulates the optic fibers in the transition segment. The assembly further includes multiple optic fiber legs each terminated with a fiber optic connector according to the specification. Optic fibers extending beyond a boundary of the polymeric material are subject to being mass fusion spliced to another group of multiple optic fibers, and the fusion splices encapsulated with polymeric material, to form a fiber optic cable assembly. Methods for fabricating multi-fiber assemblies providing fan-out functionality are further provided, and the need for furcation tubes shall be avoided.

US20180109062A1 published on behalf of Waymo LLC on 19.04.2018, relates to a fiber encapsulation mechanism for energy dissipation in a fiber amplifying system. One example embodiment includes an optic fiber amplifier. The optic fiber amplifier includes an optic fiber that includes a gain medium, as well as a polymer layer that at least partially surrounds the optic fiber. The polymer layer is opticly transparent. In addition, the optic fiber amplifier includes a pump source. Optic pumping by the pump source amplifies optic signals in the optic fiber and generates excess heat and excess photons. The optic fiber amplifier additionally includes a heatsink layer disposed adjacent to the polymer layer. The heatsink layer conducts the excess heat away from the optic fiber. Further, the optic fiber amplifier includes an opticly transparent layer disposed adjacent to the polymer layer. The opticly transparent layer transmits the excess photons away from the optic fiber. US2017075067A1 published on behalf of II VI Inc. on 16.03.2017, relates to a micro splice protector for a fusion connection between a pair of optic fibers, which splice protector takes the form of a cylindrical sleeve of dimensions similar to that of the fusion splice itself. An epoxy material is used to encase the fusion splice within the sleeve. The sleeve is formed to exhibit an inner diameter only slightly greater than the outer diameter of the optic fibers, with the length of the sleeve typically formed to be only slightly longer than the stripped end terminations of the pair of fibers being spliced together. The cylindrical sleeve is formed of a rigid, but lightweight, material and an epoxy material is injected into the configuration to fill any gaps between the fusion connection and the inner surface of the sleeve.

US2015253503A1 published on behalf of AFL Telecommunications Lie. on 10.09.2015, relates to a method of assembling a transition assembly. The method described herein may comprise stripping a plurality of fibers at an end of a cable; splicing the plurality of fibers from the cable with a plurality of pigtails and protecting the bare fiber with a cover. The transition assembly may comprise a fiber protection part and a cover that covers the fiber protection part. The fiber protection part may have openings.

SUMMARY OF THE DISCLOSURE

Fan-out assemblies are known from the prior art for dividing a fiber optic trunk cable, comprising a bundle of optic fibers, into a number of individual fiber optic cables usually terminated by an optic connector (so called pigtails). They are e.g. used as components in cabling systems to interconnect computers and other network components to enable them to communicate. Such cabling systems can be used both for indoor as well as outdoor applications. Typical indoor applications of cabling systems include space saving connections of transmitting and receiving entities of optic data links, like in crowded cable conducts, e.g. in data centers in a rack-to-rack assembly. Typical outdoor applications include the connection of cellular base stations to radio heads, etc.

The optical fibers are usually spliced in the fan-out assembly in that a first fiber and a second fiber are interconnected to each other by a splice or a fiber is divided and then spliced again. Good results can be achieved by fusion-splicing. The current state-of-the-art concerning treatment of fusion-spliced fiber sections dictates that said fiber sections are packaged in a stress-free and quasi-hermiti- cally sealed manner. Any deviation from this state-of-the-art requires extensive measures to proof the intended fiber protection concept and method. The safely tolerable strain I stress induced in the fusion-spliced fiber sections may be derived from the currently accepted strain during lifetime versus failure probability (i.e. fiber breakage) models and recommendations. Appropriate reduction factors have to be applied. High-reliability splices (e.g., as used in sub-sea cable systems) usually require specialized splicers and are always proof-tested to fairly high strain levels.

Fan-out assemblies known from the prior art have difficulties to fulfill the necessary requirements in a cost efficient manner. A further problem which often occurs with the fan-out assemblies known from the prior art is the mechanical stress applied to the fibers in axial direction when the fan-out assembly is under tension. Instead of splitting up the stripped fibers from the trunk cable, feeding them through empty tubes and assembling connectors to them, the present disclosure offers the possibility to provide prefabricated fiber cable pigtails with connectors. The fiber cable pigtails are spliced to the individual fibers of the trunk cable. This allows a modular manufacturing and results in a much easier handling during termination of the connectors since not the whole fiber optic fan-out assembly has to be handled in this process step. Since the splicing operation usually requires a significant length of exposed fiber - nowadays typically in the range of 10 cm to 20 cm - they need to be protected well again in a housing of the fan-out assembly after splicing. For easier use in narrow spaces, it is of advantage if the housing of the fan-out assembly is not all rigid.

Outer loads, applied onto the trunk cable or the fiber pigtails can typically be mitigated by an optimized design of e.g. the housing and outer components of the fiber optic fan-out assembly, e.g. by attaching the components to the entry and exit section of the fiber optic fan-out assembly by e.g. gluing, or by using strain relieve means. In comparison, stress/strain applied to the optic fibers within the fiber optic fan-out assembly are more difficult to mitigate. Stresses induced by exposure to thermal cycling or permanent heat and humidity are considered the most critical exposures to the fiber optic fan-out assembly during its lifetime and are more difficult to compensate.

A fiber optic fan-out assembly according to the present disclosure comprises in an assembled state a housing through which a cable arrangement extends as described in more detail hereinafter. The cable arrangement comprises a trunk cable comprising optic fibers in form of a bundle or in form of at least one ribbon, which can be encompassed by a trunk cable sheathing. The cable arrangement further comprises a number of pigtails, which are arranged opposite to the trunk cable with respect to the housing. The cable arrangement may be pre-assembled in an upstream assembly step wherein the trunk cable is cut to length and the end is stripped from the trunk cable sheathing such that the optic fibers become accessible for processing. The same applies to the pigtails, which usually comprise a fiber optic cable with at least one optic fiber terminated by an optic connector. Under normal conditions, the fiber optic cable of each pigtail comprises a sheathing encompassing the at least one optic fiber. As mentioned above, the pigtails may be prefabricated. For interconnection to the fibers of the trunk cable, the cable sheathing of each optical cable is stripped in the end region opposite to the connector before it is spliced to the corresponding pigtail. The cable assemblies comprising the trunk cable and the thereto interconnected pigtails may be prefabricated if appropriate. In a downstream assembly step, the prefabricated cable arrangement is arranged inside a housing, which comprises an installation space accessible from a lateral side. The method for assembling the fiber optic fan-out assembly according to the present disclosure will be discussed in more detail below noted.

The housing preferably comprises two housing parts, which can be assembled with each other such that they encompass the cable assembly at least in the area where the optic fibers are stripped. The optic fibers are typically routed and shuffled from the trunk cable, via the housing to corresponding pigtails. The housing typically extends in an axial direction and encompasses a first cable passage through which the optic fibers of the trunk cable enter the housing. The housing usually comprises a transition space and a deflection space arranged with respect to the axial direction behind the first cable passage, through which the optic fibers extend in the axial direction. Depending on the design, the transition space is along the axial direction and with respect to the first cable passage arranged behind the deflection space. Alternatively, the deflection space can be arranged behind the transition space. At the opposite end, the housing preferably comprises a second cable passage through which the optic fibers exit the housing into the pigtails. Depending on the design, also a housing without a deflection space is possible.

Depending on the assembly method, the housing can encompass behind each other the first cable passage through which the optic fibers of the trunk cable enter the housing, the transition space through which the optic fibers extend in the axial direction which transition space acts as integrated splice protector, the deflection space in which the optic fibers are deflected forming at least one hump extending in a lateral direction and the second cable passage through which the optic fibers exit the housing into the pigtails. Alternatively, the housing can encompass behind each other the first cable passage through which the optic fibers of the trunk cable enter the housing, the deflection space in which the optic fibers are deflected forming at least one hump extending in a lateral direction, the transition space through which the optic fibers extend in the axial direction which transition space acts as integrated splice protector, and the second cable passage through which the optic fibers exit the housing into the pigtails. The first and/or the second cable passage may be a cable gland. To avoid stress/ strain due to both, external influences as well as internal influences, e.g. creeping of the housing or other components of the fiber optic fan-out assembly, the optic fibers are preferably laterally deflected forming at least one hump. Good results can be achieved when this is introduced during the assembly of the present fiber optic fan-out assembly. To provide a fiber over length for e.g. at least temporarily compensating length fluctuations in the axial direction a deflection space is typically arranged in the housing behind the transition space with respect to the axial direction, in which the optic fibers are deflected forming at least one hump arranged in the so called deflection space extending in a lateral direction. The hump in this area is preferably arranged without support such that it can extend in a natural manner. The deflection space can be a hollow installation space formed by air. Alternatively, the deflection space can be filled with a flexible material, which allows length deviations and movement of the optic fibers along the axial direction and/or at least one lateral direction. Good results can be achieved when the optic fibers are arranged such that the resulting hump (buckle) is shaped similar to the theory of an Euler beam with to fixed ends, which are deviated against each other until the beam buckles there between. Alternatively or in addition, the optic fibers may be deflected in a spiral form.

To ensure that the optic fibers are deflected in the deflection space in a controlled manner, the transition space and the deflection space may be delimited from each other by a constraint by which the optic fibers are positioned with respect to each other. The optic fibers may be interconnected to the housing the region of the constraint, e.g. by gluing. Depending on the design of the housing, the housing can be torpedo-shaped and comprise compartments, which are designed in form of channels, which extend in the axial direction and are arranged next to each other. The compartments can be delimited by at least one constraint, comprising e.g. at least one recess in which the optic fibers are arranged in stacked manner. Alternatively or in addition, the constraint may comprise at least two recesses, which are arranged parallel to each other configured to space at least two optic fibers laterally apart from each other.

In an alternative variation, the housing of the fan-out assembly can comprise a first housing part, which is shaped like a revolver drum. The second housing part can be designed as a slotted cover shell in which the revolver shaped drum can be inserted. The revolver shaped drum typically comprises a number of compartments arranged in a rotational symmetric manner with respect to the axial direction. The transition space and the deflection space may be delimited from each other by a constraint, which comprises several recesses which are arranged in a rotational symmetric manner in which at least one optic fibers are arranged each. If a compartment of the revolver shaped drum is aligned with the slot of the cover shell, a compartment of the revolver shaped drum is accessible such that an optic fiber and a respective pigtail can be inserted into the compartment. During the assembly, the revolver shaped drum may be rotated within the first housing part, until a respective optic fiber and a respective pigtail are placed in each compartment.

To allow a deflection of the optic fibers in a controlled manner within the housing, the optic fibers are usually fixated on both sides of the housing, providing a fixed support. The optic fibers can be attached to the first cable passage of the housing and/or the second cable passage of the housing by e.g. a potting compound or an adhesive. Besides attaching the optic fibers and/or pigtails to the housing, the optic fibers may at least partially be embedded in a potting compound in the transition space. The optic fibers may thereby be essentially arranged parallel to each other in the transition space. To allow access to the transition space for applying the potting compound, the potting compound can be applied when the housing is partially open or closed. The potting compound used to attach the optic fibers can be a fast UV curable Epoxy. UV curing potting compounds have the advantage of almost unlimited pot-life with no component mixing requirement. Besides being configured to receive at least one optic fiber, the constraint can act as a sealing means and/or a sealing means may be arranged adjacent to the constraint to prevent spilling of a potting compound.

Depending on the design of the cable arrangement, the optic fibers can be either continuous fibers from the trunk cable throughout the pigtails or the optic fibers of the trunk cable can be connected to optic fibers of the pigtails, preferably by a splicing operation forming a splice. The splicing operation can be done, e.g. in advance of the actual assembly and the spliced cable arrangement may be temporarily stored for the actual assembly. Typical splice processes include fusion splicing methods, e.g. arc discharge fusion splicing or filament fusion splicing. In case that the optic fibers of the trunk cable are connected to the optic fibers of the pigtail section by a splicing operation, the splice requires thorough protection to avoid being damaged or avoid a rupture of the connected optic fibers at the splice. The splice of the optic fibers is arranged in the transition space.

Good results can be achieved when the at least one splice is arranged in a compartment of the transition space which is limited by opposing partition walls of the housing. The splice is typically embedded by a block of potting compound. The at least one splice can be arranged in a compartment of the housing limited by opposing partition walls and/or be at least partially embedded in a potting compound. Good results can be achieved when the housing comprises a first housing part and/or a second housing part which is at least partially made from an UV transparent plastic, such that a therein arranged potting compound can be cured even when the housing is closed. The potting compound can be made of an acrylate, which is configured to bear the loads applied onto the fibers and prevent the spliced fiber sections from buckling during the lifetime, even at elevated temperatures. Furthermore, they cure fairly fast without generating much heat and the resulting stress. The first housing part may comprise with respect to the axial direction a lateral recess for routing the optic fibers into the first housing part. The recess can be beneficial for routing the already spliced optic fibers into the housing by keeping the bending radii as low as possible. This allows also to keep the stripped section of the trunk cable and/or pigtails shorter compared to known methods whereby up to 300 mm of the trunk cable need to be stripped. To avoid crossing or twisting of the optic fibers within the housing, the optic fibers can be routed such that the fiber of the trunk cable which is most proximal to the housing is spliced and routed first. The routing within the housing is preferably done such that the order of fibers is the same as in the fiber tray. The splicing operation can then be continued subsequently with the fibers being spliced one after another with the optic fiber of the trunk cable being furthest away from the housing being spliced and routed last.

While the outer loads can typically be dissipated via the housing, e.g. by attaching the optic fibers to the first cable passage of the housing (entry section) and the pigtails are attached to an opposite second cable passage (exit section) of the housing, the inner loads are more difficult to mitigate or compensate. To prevent especially a potential splice being strained or ruptured by this force, the splice may be protected by a splice protector. The state-of-the-art treatment of spliced fiber sections is to pack the spliced fiber sections in a stress-free and quasi-her- mitically sealed splice protection. Nevertheless, since a slim silhouette of fiber optic fan-out assemblies is required to be able to fit the fiber optic fan-out assemblies in confined spaces, standard splice protectors in form of a splice cassettelike arrangement, combined with fiber over length management, are not an option as they are to bulky.

Before attaching both the optic fibers to the first cable passage of the housing and attaching the pigtails to the second cable passage of the housing, the trunk cable and the pigtails are moved with respect to each other such that the optic fibers are in a deflection section of the housing laterally deflected with respect to the axial direction, to prevent tensile stress of the optic fibers during operation. The trunk cable and the pigtails can be moved with respect to each other by a specific distance in the axial direction. In order to deflect all fibers as evenly as possible, the pigtail bundle may be glued or taped together, during or after stacking the optic fibers into the housing. Good results can be achieved when the optic fibers are laterally deflected in a manner, such that the deflected optic fibers form an Euler beam. The over length is created to primarily compensate thermally induced expansion and contraction of the entire fiber optic fan-out assembly or components thereof, e.g. the housing. To ensure, that the fibers are deflected sufficiently without being overstrained, an assembly device can be used which is configured to move the trunk cable and the pigtail section with respect to each along the axial direction by a pre-defined axial displacement with respect to the axial direction.

As stated above noted already, the housing may comprise a first housing part which is interconnectable to a second housing part. The second housing part can be designed as a shell like cover, which is held in place in the finished fan-out assembly by an outer tube, which is arranged at least partially encompassing the housing in the assembled state. The second housing part can be attached to the first housing part by a snap-fit or any other suitable means, or be glued to the first housing part or ultra-sonic or laser welded to the latter. Besides protecting the optic fibers on the inside of the housing, also the protection of the section of the optic fiber between housing and trunk cable is critical. To protect the optic fibers of this section from external loads, the previously stripped trunk cable can be rebuilt using a bendable cable kink protector, which can be slided over the cable in form of a fiber bundle or at least one fiber optic ribbon. The main purpose is to protect the fiber bundle or the at least one ribbon, mainly from kinking due to cable jacket shrinkage or cable bending. A helical cable kink protector can be attached to the first cable passage of the housing which encompasses the optic fibers of the trunk cable. Alternatively, the section between the housing and the trunk cable can be over molding to form the boot, although this results in a significant, unwanted heat influx. Also, simple shrink tubes may be used, although the attachment also results in a significant, unwanted heat influx.

Good results can be achieved when a fiber layer is at least partially wound about the optic fibers and the housing, which fiber layer is configured to act as a strain relief means between the housing and the trunk cable. The fiber layer can be attached to the trunk cable by gluing the strain relief filaments to the trunk cable sheathing, around the cable kink protector and attaching it to the housing. The fiber layer may avoid relative length fluctuations of the optic fibers due to cable shrinkage, cable pulling and cable bending. The strain relief filaments from the trunk cable (and from the fiber bundle tube, if any) can be combed backwards over a cable jacket of the trunk cable by a protective sleeve and held in place by an outer tube in the assembled state. The strain relief filaments from the trunk cable can be evenly wound about the cable kink protector and the housing. As an alternative, strain relief filaments can be routed on the inside (i.e. alongside the optic fibers of the transition section), although this may reduce the kinking protection of the same. As a further alternative, strain relief filaments can be combined in a number of bundles and routed and attached as such.

To protect the overall fiber optic fan-out assembly against environmental exposure (e.g., water ingress, chemical attack), the housing and the section of the optic fibers between the housing and the trunk cable can be sealed by a protective sleeve, which can be e.g. crimped onto the trunk cable. The protective sleeve can be slid over the strain relief filaments onto the end of the housing and later held in place by an outer tube, which can be typically mounted in the last assembly step. As an alternative, the protective sleeve can be glued onto the strain relief filaments and the housing. Alternatively or in addition, an outer tube can be mounted onto the housing to stabilize the thin-walled housing and increase the overall robustness of the fiber optic fan-out assembly. As an alternative, the first and second housing part (i.e. lower shell and cover) can be made from a reinforced material and more thick-walled, although a more thick-walled housing may lower the UV transparency for curing the potting compounds and the acrylate. The outer tube is typically in addition used to clamp the strain relief fiber layer (and from the fiber bundle tube, if any) to the housing.

A method for assembling a fiber optic fan-out assembly typically comprises at least the following method steps:

• Providing a housing which encompasses in the axial direction a first cable passage, a transition space, a deflection space and a second cable passage;

• Providing a cable arrangement, which comprises a trunk cable including optic fibers in form of a bundle of optic fibers or at least one ribbon, which are preferably encompassed by a trunk cable sheathing. The optic fibers extend into a number of pigtails.

• Arranging the cable arrangement in the housing such that the optic fibers of the trunk cable enter the housing through the first cable passage, extend across the transition space and the deflection space in the axial direction and exit the housing through the second cable passage into the pigtails;

• Before attaching the optic fibers both to the first cable passage and the second cable passage, the trunk cable and the pigtails are moved with respect to each other by a specific distance, such that the optic fibers in the deflection section are deflected forming a hump extending in a lateral direction. Instead of splitting up the stripped optic fibers from the trunk cable, in which the optic fibers are arranged e.g. in form of a bundle with multi-fibers or a ribbon, and being individually fed through empty tubes before assembling connectors to them, a number of prefabricated pigtails with thereto-attached connectors can be spliced to the optic fibers of the trunk cable. The advantage of this design is a modular assembly, which makes the handling during termination of the connectors much easier since not the whole fiber optic fan-out assembly has to be handled in this process.

With the known standard splicing operations and assembly methods of fiber optic fan-out assemblies, a significant length of stripped optic fibers is necessary. Usually about 150 to 300 mm of the trunk cable needs to be stripped. The problem is that the stripped section is very fragile and prone to damages. Therefore, after the splicing operation, this comparatively long section of spliced trunk cable and optic fibers needs to be especially protected. Therefore, the overall fiber optic fanout assembly is typically wrapped up in at least one fiber layer. This results in a comparatively long overall length of the fiber optic fan-out assembly. Especially in narrow spaces such a long and rigid fiber optic fan-out assembly is usually to inflexible for routing.

In a preferred solution the required length for splicing/handling is reduced, such that also the overall length of the fiber optic fan-out assembly can be reduced. A method for assembling such a shortened fiber optic fan-out assembly typically comprises at least the following method steps: a. providing a housing, encompassing in an axial direction a first cable passage and a second cable passage; b. providing a trunk cable including optic fibers in form of a bundle of optic fibers and/or at least one ribbon, preferably encompassed by a trunk cable sheathing; c. providing a number of pigtails, each of the pigtails comprising one optic fiber; d. splicing the optic fiber of one of the number of pigtails to one of the optic fibers of the trunk cable; e. placing the optic fiber of the pigtail spliced to one of the optic fibers of the trunk cable into the housing, such that the optic fiber of the pigtail extends in axial direction and exits the housing through the second cable passage into the pigtail; f. repeating steps d. and e. until all of the optic fibers of the number of pigtails are spliced to optic fibers of the trunk cable and placed into the housing.

In this method, the housing can encompass, in the axial direction, additionally a transition space and/or a deflection space.

The method can further comprise the step of placing the trunk cable into the housing, such that trunk cable enters the housing through the first cable passage. This step is preferably conducted either after step b. or f. Initially, a segment of the trunk cable sheating and/or a segment of the pigtail sheating is typically stripped before the splicing operation. After the stripping operation, the stripped optic fibers from both sides, the stripped optic fibers on the side of the trunk cable and the stripped optic fibers on the side of the number of pigtails, are each preferably placed in a slot of a tray. The tray can be part of the splicing device, or it can be a separate component, which is inserted into or placed adjacent to the splicing device. In any case, during steps d. to f., unspliced optic fibers and pigtails remain outside the housing. Good results can be achieved when the optic fibers of the trunk cable are singularized and each optic fiber is placed in a respective slot of a fiber tray and/or the pigtails are singularized and each pigtail is placed in a respective slot of a pigtail tray before the splicing operation. The unspliced optic fibers and pigtails can be arranged essentially parallel to the axial direction of the housing or the housing can be arranged diagonal with respect to the unspliced optic fibers and pigtails, wherein the first cable passage faces the trunk cable. The spliced optic fibers are fed, usually one after another, either manually or automatically to the splicing process. In other words, an end of a singularized optic fiber of the trunk cable and an end of the optic fiber of a singularized pigtail can be aligned with each other and spliced with each other, preferably by fusion splicing.

The size of the splicing equipment and space needed for handling the optic fibers in the splicing device essentially defines the required length of the trunk cable and the pigtails to be stripped before performing the splicing operation. With the present method, the splicing typically requires at least 10 mm stripped fibers on each sides. 10 mm on the side of the trunk cable and 10 mm on the side of the number of pigtails. In addition, typically another approximately 45 mm of the sheating of the trunk cable needs to be stripped. This can be necessary to be able to handle the optic fibers in the splicing device and after the splicing operation for routing them into the housing. To be able to keep the stripped length as short as possible, the stripped optic fibers of the trunk cable which are typically placed in a fiber tray, the stripped optic fibers of the pigtails which are typically placed in a pigtail tray and the housing shall be placed as close to the splicing device as possible.

Typically, the optic fibers are spliced sequentially one after another. The fiber pairs, one stripped optic fiber of the trunk cable and one stripped optic fiber of one of the number of pigtails, are one after the other moved into the splicing position. Typically, the cover/housing of the splicing device is removed for being able to arrange the fiber tray for the stripped optic fibers of the trunk cable, the pigtail tray for the stripped optic fibers and the housing. The splicing device typically comprises e.g. electrodes to generate the welding-arc or a laser, and a holder to hold the optic fibers in position during the splicing operation, to ensure that the ends are not laterally displaced with respect to each other. The holder can comprise at least one gripper, which can be used to hold the end of a singu- larized optic fiber of the trunk cable and the end of the optic fiber of a pigtail within the splicing device. Separate grippers can be used, with a first gripper for holding the end of the optic fiber of the trunk cable in place and a second gripper for holding the end of the optic fiber of the pigtail in place.

In one embodiment, all trays - especially the fiber tray and the pigtails tray - are placed in one carrier. This allows placing all cables, fibers and the housing into their start position outside of the splicing device (while the device is processing an earlier batch). The filled carrier is then placed on the splicing device, the fibers are spliced sequentially and placed into the housing. After this, the carrier is removed (so another batch can be started) and the final process steps like potting and closing are made outside of the station. In a variation, the carrier is placed next to the splice device. The splice device can be placed between the carrier and the housing. In a variation, the carrier is arranged elevated with respect to the splice device.

The optic fibers can be spliced by using a fusion splicer. The fusion splicer typically uses an electric arc and handling equipment which may be modified to perform the splicing operation with reduced stripped optic fiber length. To be able to use a shorter housing, e.g. with a length of less than 100 mm, preferably 75 mm, the trunk cable is stripped on a length of about 65 mm and 10 mm of the pigtail, preferably resulting in approximately 75 mm for both sides together. In a preferred variation, an optimized splice devise is used without a cover and a handling system for arranging the singularized optic fiber of the trunk cable and the optic fiber of the pigtail in the splicing position.

After the splicing operation, the already spliced optic fiber of the trunk cable and the thereto spliced optic fiber of the pigtail can be routed into the housing via a lateral recess in the first and/or second housing part. Alternatively, the housing can be tipped with respect to the axial direction for routing the already spliced optic fiber of the trunk cable and the thereto spliced optic fiber of the pigtail into the housing without overstraining the optic fibers through bending. After the routing through the recess, the pigtail is thereby preferably already arranged in the second cable passage. Once all optic fibers of the trunk cable are each spliced to a respective pigtail, the optic fibers and thereto interconnected trunk cable are arranged in the housing and the trunk cable is arranged in the first cable passage. Before attaching the trunk cable to the first cable passage and the pigtails to the second cable passage, the trunk cable and the pigtails are typically moved with respect to each other by a specific distance, such that the optic fibers in the deflection space are deflected forming a hump extending in a lateral direction.

The optic fibers of the trunk cable are typically attached to the first cable passage and/or the pigtails are attached to the second cable passage by a potting compound. After having placed all the optic fibers of the trunk cable and the pigtails into the housing and attaching them by the potting compound, the hosing can be closed and a fiber layer at least be partially wound about the optic fibers and the housing, thereby attaching the first housing part to the second housing part and sealing the first and/or the second cable passage against environmental influences.

Alternatively to placing the already spliced fibers stepwise partially in the housing and moving the trunk cable at the end, it would also be possible in a first step to splice all optic fibers of the trunk cable to pigtails and keep the spliced optic fibers in a fixture and in a second step arrange all spliced optic fibers in one step into the housing. As this variation requires a complex handling system, to be able to prevent the splices from being damaged, while arranging the trunk cable and pigtails in their respective position in the housing, a laser splicing process is preferred. Laser splicing makes it possible to first arrange the optic fibers in the housing which allow to further reduce the stripped length and splice the optic fibers of the trunk cable to the optic fibers of the pigtails, while already being arranged in the housing.

For assembling the fiber optic fan-out assembly an assembly device typically comprises a holding device which comprises at least a first clamping means, configured for holding the first housing part while the cable arrangement is arranged within the first housing part. Arranging the cable arrangement in the housing is typically carried out by a (semi-) automated, vision assisted and controlled, fiber insertion workstation to handle and insert the cable arrangement into the housing. The assembly device typically further comprises a moving unit, which comprises at least a second clamping means, configured for holding the pigtails and moving the trunk cable and the pigtail section with respect to each other.

The second clamping means can be displaced with respect to the first clamping means along the axial direction such that the trunk cable and the pigtails are moved with respect to each other by a specific distance in the axial direction. Depending on the design, the splicing operation can be performed in am upstream assembly step or during the assembly of the cable fan-out assembly. The assembly device can therefore comprises a splicing unit configured to splice in the transition section at least one optic fiber of the trunk cable to a corresponding optic fiber of the pigtail section.

It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

Fig. 1 a perspective view from the back and above on a first variation of the fiber optic fan-out assembly depicted in an exploded manner;

Fig. 2 a perspective view from the back and above on a first variation of the housing and the cable arrangement of the fiber optic fan-out assembly according to Figure 1 ;

Fig. 3 a perspective view from the back and above on a first variation of the housing and the cable arrangement according to Figure 2 with added potting compound;

Fig. 4 an enlarged perspective cut-out of Figure 3, showing the optic fibers arranged in the transition space; Fig. 5 a perspective view from the back and above on a first variation of the housing and the cable arrangement according to Figure 3 with added potting compound and cable kink protector;

Fig. 6 an enlarged perspective cut-out of Figure 5, showing the optic fibers arranged in the deflection space;

Fig. 7 a perspective view from the back and above on a first variation of the housing and the cable arrangement according to Figure 5 with added fiber layer;

Fig. 8 a perspective view from the back and above on a first variation of the housing and the cable arrangement according to Figure 7 with added outer tube and protective sleeve;

Fig. 9 a perspective view from the back and above on a second variation of the fiber optic fan-out assembly with a partial cut out;

Fig. 10 a perspective view from the back and above on the second variation of the fiber optic fan-out assembly according to Figure 9 in an exploded manner;

Fig. 11 a perspective view from the back and above on a third variation of the fiber optic fan-out assembly; Fig. 12 a perspective view from the back and above on the splicing operation of the third variation according to Figure 11 with already partially routed spliced fibers;

Fig. 13 a perspective view from the back and above on an assembly station showing a first assembly step of the fiber optic fan-out assembly ac- cording to Figure 11 ;

Fig. 14 an enlarged view of the first assembly step according to Figure 13;

Fig. 15 a perspective view from the back and above on the assembly station showing a second assembly step of the fiber optic fan-out assembly according to Figure 11 ;

Fig. 16 an enlarged view of the second assembly step according to Figure 15;

Fig. 17 a perspective view from the back and above on the assembly station showing a third assembly step of the fiber optic fan-out assembly according to Figure 11 ; Fig. 18 an enlarged view of the third assembly step according to Figure 17.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

Figure 1 shows a perspective view from the back and above on a first variation of the fiber optic fan-out assembly 1 depicted in an exploded manner. The shown fiber optic fan-out assembly 1 comprises a cable arrangement 2 and a housing 7. The cable arrangement 2 comprises a trunk cable 3 comprising optic fibers 4 in form of a bundle, which are each encompassed by a trunk cable sheathing 5. The shown cable arrangement 2 further comprises a number of Pigtails 6, which are arranged opposite to the trunk cable 3 with respect to the housing 7. The housing 7 of the shown variation extends in an axial direction x and encompasses behind each other a first cable passage 8 through which the optic fibers 4 of the trunk cable 3 enter the housing 7. The housing 7 typically further comprises a transition space 9 arranged with respect to the axial direction x behind the first cable passage 8, through which the optic fibers 4 extend in the axial direction x. To avoid stress/ strain due to both, external influences as well as internal influences, e.g. creeping of the housing 7 or other components of the fiber optic fanout assembly 1 , the optic fibers 4 can be at least partially laterally deflected during the assembly of the present fiber optic fan-out assembly 1 . To provide a fiber over length for e.g. at least temporarily compensating length fluctuations in the axial direction x a deflection space 10 is arranged in the housing 7 behind the transition space 9 with respect to the axial direction x, in which the optic fibers 4 are deflected forming at least one hump 11 extending in a lateral direction y,z. The shown housing 7 further comprises a second cable passage 12 through which the optic fibers 4 exit the housing 7 into the pigtails 6.

Figure 2 shows a perspective view from the back and above on a first variation of the housing 7 and the cable arrangement 2 of the fiber optic fan-out assembly 1. The shown cable arrangement 2 is pre-assembled in an upstream assembly step, wherein the trunk cable 3 is cut to length and the end is stripped such that the optic fibers 4 become accessible. In the shown assembly step, the cable arrangement 2 is arranged within the housing 7, wherein the optic fibers 4 are routed from the trunk cable 3, via the housing 7 to corresponding pigtails 6. The shown housing 7 encompasses in the axial direction x behind each other a first cable passage 8, a transition space 9 in form of two parallel channels 23, a deflection space 10 and a second cable passage 12. The cable arrangement 2 which comprises a trunk cable 3 including optic fibers 4 in form of a bundle of optic fibers 4 which are each encompassed by a trunk cable sheathing 5 and extend into a number of pigtails 6. The cable arrangement 2 is arranged in the housing 7 such that the optic fibers 4 of the trunk cable 3 enter the housing 7 through the first cable passage 8, extend across the transition space 9 and the deflection space 10 in the axial direction x and exit the housing 7 through the second cable passage 12 into the pigtails 6.

Figure 3 shows a perspective view from the back and above on the first variation of the housing 7 and the cable arrangement 2 with added potting compound 15. To allow a deflection of the shown optic fibers 4 in a controlled manner within the housing 7, the optic fibers 4 are fixated on both sides of the housing 7, providing a fixed support. The optic fibers 4 are attached to the first cable passage 8 of the housing 7 and/or the second cable passage 12 of the housing 7 a potting compound 15 or an adhesive. Besides attaching the optic fibers 4 and/or pigtails 6 to the housing 7, the optic fibers 4 are embedded in a potting compound 15 in the transition space 9. The optic fibers 4 are thereby be essentially arranged parallel to each other in the transition space 9. To allow access to the transition space 9 for applying the potting compound 15, the potting compound 15 is applied when the housing 7 is partially open. The shown potting compound 15 used to attach the optic fibers 4 is a fast curable UV curable Epoxy.

Figure 4 shows an enlarged perspective cut-out of Figure 3, showing the optic fibers 4 arranged in the transition space 9. The shown transition space 9 and the deflection space 10 are delimited from each other by a constraint 13 by which the optic fibers 4 are positioned with respect to each other. The shown design of the housing 7, is torpedo-shaped and comprise compartments 19, which are designed in form of channels 23 and extend in the axial direction x and are arranged next to each other. The shown compartments 19 are delimited by at least one constraint 13 which comprises recesses 14 in which the optic fibers 4 are arranged in stacked manner. The shown constraint 13 comprises two recesses 14, which are arranged parallel to each other configured to space the optic fibers 4 laterally apart from each other. Before the optic fibers 4 are deflected in the deflection space 10 in a controlled manner, the optic fibers 4 in the transition space 9 are embedded by potting compound 15.

Figure 5 shows a perspective view from the back and above on a first variation of the housing 7 and the cable arrangement 2 according to Figure 3 with added potting compound 15 and cable kink protector 21. Besides protecting the optic fibers 4 on the inside of the housing 7, also the protection of the section of the optic fibers 4 between housing 7 and trunk cable 3 is critical. To protect the optic fibers 4 of this section from external loads, the shown previously stripped trunk cable 3 is re-built, using a bendable cable kink protector 21 , which is wound around the fiber bundle. The main purpose is to protect the fiber bundle, mainly from kinking due to cable jacket shrinkage or cable bending. The shown helical cable kink protector 21 is wound around the first cable passage 8 of the housing 7, which encompasses the optic fibers 4 of the trunk cable 3. In the shown variation the optic fibers 4 can be either continuous fibers from the trunk cable 3 throughout the pigtails 6 or the optic fibers 4 of the trunk cable 3, which are connected to optic fibers of the pigtails 6, preferably by a splicing operation forming a splice. The splice 18 requires thorough protection to avoid being damaged or avoid a rupture of the connected optic fibers 4 at the splice 18. The splice 18 of the optic fibers 4 is therefore arranged in a compartment 19 of the transition space 9 which is limited by opposing partition walls 20 of the housing 7. The splice 18 is typically embedded by a block of potting compound 15.

Figure 6 shows an enlarged perspective cut-out of Figure 5, showing the optic fibers 4 arranged in the deflection space 10. The shown splices 18 are arranged in compartments 19 of the housing 7, which are limited by opposing partition walls 20 and/or be at least partially embedded in a potting compound 15. Before attaching both, the optic fibers 4 to the first cable passage 8 of the housing 7 and attaching the pigtails 6 to the second cable passage 12 of the housing 7, the trunk cable and the pigtails 6 are moved with respect to each other such that the optic fibers 4 are in the deflection section 10 of the housing 7 laterally deflected with respect to the axial direction x. To prevent tensile stress of the optic fibers 4 during operation the trunk cable and the pigtails 6 are moved with respect to each other by a specific distance d1 in the axial direction x. In order to deflect the optical fibers 4 as evenly as possible, the shown pigtails 6 are glued or taped together, during or after stacking the optic fibers 4 into the housing 7.

Figure 7 shows a perspective view from the back and above on a first variation of the housing 7 and the cable arrangement according to Figure 5 with added fiber layer 22. As stated above noted already, the housing 7, like in the shown variation, comprises a first housing part which is interconnectable to a second housing part (not shown). The second housing part can be designed as a shell like cover, which is held in place in the finished fan-out assembly by an outer tube, which is arranged at least partially encompassing the housing 7 in the assembled state. The second housing part can be attached to the first housing part by a snap-fit or any other suitable means, or be glued to the first housing part or ultra-sonic or laser welded to the latter. In the shown variation a fiber layer 22 is at least partially wound about the optic fibers and the housing 7, which fiber layer 22 is configured to act as a strain relief means between the housing 7 and the trunk cable 3. The fiber layer 22 is attached to the trunk cable 3 by gluing the strain relief filaments to the trunk cable sheathing 5, around the cable kink protector 21 and attaching it to the housing 7. The fiber layer 22 is configured to avoid relative length fluctuations of the optic fibers 4 due to cable shrinkage, cable pulling and cable bending.

Figure 8 shows a perspective view from the back and above on a first variation of the housing 7 and the cable arrangement according to Figure 7 with added outer tube 24 and protective sleeve 25. To protect the overall fiber optic fan-out assembly 1 against environmental exposure (e.g., water ingress, chemical attack), the housing 7 and the section of the optic fibers 4 between the housing 7 and the trunk cable 3 are sealed by a protective sleeve 25, which can is crimped onto the trunk cable 3. The protective sleeve 25 is slided over the strain relief filaments onto the end of the housing 7 and later held in place by an outer tube 24, which can be typically mounted in the last assembly step. As an alternative, the protective sleeve 25 can be glued onto the strain relief filaments and the housing 7. In addition, an outer tube 24 is mounted onto the housing 7 to stabilize the thin-walled housing 7 and increase the overall robustness of the fiber optic fan-out assembly 1 . The strain relief filaments from the trunk cable 3 are combed backwards over the cable jacket of the trunk cable 3 by the protective sleeve 25 and held in place by an outer tube 24 in the assembled state. The strain relief filaments from the trunk cable 3 can be either evenly wound about the spiral shaped cable kink protector 21 , which is wound around the optical fibers 4 before the strain relief filaments are wound about the spiral shaped cable kink protector 21 and the housing 7, or can be routed on the inside e.g. alongside the optic fibers 4.

Figure 9 shows a perspective view from the back and above on a second variation of the fiber optic fan-out assembly 1 with a partial cut out. Figure 10 shows a perspective view from the back and above on the second variation of the fiber optic fan-out assembly 1 according to Figure 9 in an exploded manner. In the shown variation, the housing 7 of the fan-out assembly 1 comprises a first housing part 16 which is shaped like a revolver drum. The shown second housing part 17 is be designed as a slotted cover shell in which the revolver shaped drum can be inserted. The revolver shaped drum comprises a number of compartments 19 arranged in a rotational symmetric manner with respect to the axial direction x. The transition space 9 and the deflection space 10 of the shown variation are delimited from each other by a constraint 13, which comprises several recesses 14 which are arranged in a rotational symmetric manner in which at least one optic fibers 4 arranged each. If a compartment of the revolver shaped drum is aligned with the slot of the cover shell during assembly, a compartment 19 of the revolver shaped drum is accessible such that an optic fiber 4 and a respective pigtail 6 is inserted into the compartment 19. During the assembly, the revolver shaped drum may be rotated within the first housing part, until a respective optic fiber 4 and a respective pigtail 6 are placed in each compartment 19.

Figure 11 shows a perspective view from the back and above on a third variation of the fiber optic fan-out assembly 1 . Similar to the first variation of the fiber optic fan-out assembly 1 , the shown fiber optic fan-out assembly 1 comprises a cable arrangement 2 and a housing 7. The shown cable arrangement 2 comprises a trunk cable 3, comprising optic fibers 4 in form of a bundle, which are each encompassed by a trunk cable sheathing 5 and a number of pigtails 6, which are arranged opposite to the trunk cable 3 with respect to the housing 7.

In comparison to the first variation of the fiber optic fan-out assembly 1 , the housing 7 of the shown variation, extending in an axial direction x, encompasses behind each other the first cable passage 8, a deflection space 10 in which the optic fibers 4 are deflected forming at least one hump 11 and a transition space 9, through which the optic fibers 4 extend in the axial direction x. For the in comparison to the first variation shorter housing 7, with a length of less than 100 mm, preferably 75 mm, the trunk cable 3 only has to be stripped on a length of about 65 mm and a length of about 10 mm of the optic fibers of the trunk cable 3 and 10 mm of the pigtails 6 have to be stripped. As a result only approximately 75 mm of optic fibers 4, 27 for both sides together, need to be stripped. The shown first housing part 16 comprises with respect to the axial direction x a lateral recess 26 for routing the already spliced optic fibers 4, 27 into the first housing part 16. The recess 26 is beneficial for routing the already spliced optic fibers 4, 27 into the housing 7 by keeping the bending radii as low as possible. This allows to also keep the stripped section of the trunk cable 3 and/or pigtails 6 shorter compared to known methods.

Figure 12 shows a perspective view from the back and above on the assembly of the third variation of the fiber optic fan-out assembly 1 with already partially routed spliced fibers 4, 27. In the shown variation, the optic fibers 4 of the trunk cable 3 are spliced to the optic fibers 27 of the pigtails 6 by a fusion splicer. The shown fusion splicer uses an electric arc. As can be obtained from the figure, the already spliced optic fibers 4 of the trunk cable 3 and the thereto spliced optic fibers 27 of the pigtail 6 are routed into the housing 7 via the lateral recess 26 in the first housing part 16. The already spliced pigtails 6 are arranged in the second cable passage 12. Once all optic fibers 4 of the trunk cable 3 are each spliced to the optic fiber 27 of a respective pigtail 6, the optic fibers 4 and thereto interconnected trunk cable 3 are arranged in the housing 7 and the trunk cable 3 is arranged in the first cable passage 8, as shown by Figure 11. The optic fibers 4 of the trunk cable 3 are attached to the first cable passage 8 and/or the pigtails 6 are attached to the second cable passage 12 by a potting compound 15. After having placed all the optic fibers 4 of the trunk cable 3 and the pigtails 6 into the housing 7 and attaching them by the potting compound 15, the housing 7 can be closed and a fiber layer 22 at least be partially wound about the optic fibers 4, 27 and the housing 7, similar to the variation shown in Figures 7 and 8.

Figures 13 to 18 show an assembly station 38 and a method for assembling the fiber optic fan-out assembly 1. A housing 7 is provided, which encompasses in the axial direction x a first cable passage 8, a transition space 9, a deflection space 10 and a second cable passage 12. A trunk cable 3 is provided, which includes optic fibers 4 in form of a bundle of optic fibers and/or at least one ribbon, encompassed by a trunk cable sheathing 5 as well as a number of pigtails 6, which each comprise one optic fiber 27. Each of the optic fibers 27 of one of the number of pigtails 6 is spliced to one of the optic fibers 4 of the trunk cable 3. The optic fibers 27 of the pigtail 6 already spliced to one of the optic fibers 4 of the trunk cable 3 are placed sequentially one after another into the housing 7, such that the optic fiber 27 of the pigtail 6 extends in axial direction x and exits the housing 7 through the second cable passage 12 into the pigtail 6, until all of the optic fibers 27 of the number of pigtails 6 are spliced to optic fibers 4 of the trunk cable 3 and placed into the housing 7.

Figure 13 shows a perspective view from the back and above on the assembly station 38 showing a first assembly step of the fiber optic fan-out assembly 1. Initially, a segment of the trunk cable sheating 5 and/or a segment of each pigtail sheating 30 is stripped before the splicing operation. The stripped fibers 4, 27 from both sides, the optic fibers 4 on the side of the trunk cable 3 and the optic fibers 27 on the side of the number of pigtails 6 are each placed in trays 32 and 34. The size of the splicing equipment and space needed for handling the optic fibers 4, 27 in the splicing device 39 essentially defines the required length of the trunk cable 4 and the pigtails 6 to be stripped before performing the splicing operation. The splicing typically requires at least 10 mm stripped optic fibers 4, 27 on each sides. 10 mm on the side of the trunk cable 3 and 10 mm on the side of the number of pigtails 6. In addition, typically another approximately 65 mm of the sheating 5 of the trunk cable needs to be stripped.

As can be obtained best from Figure 14, which shows an enlarged view of the first assembly step, the optic fibers 4 of the trunk cable 3 are singularized and each optic fiber 4 is placed in a respective slot 31 of the fiber tray 32 and the pigtails 6 are each singularized and placed in a respective slot 33 of the pigtail tray 34, before the splicing operation takes place. In the shown variation, the unspliced optic fibers 4, 27 and pigtails 6 are arranged essentially parallel to the axial direction of the housing 7 and fed, usually one after another, either manually or automatically to the splicing process. The optic fibers 4, 27 are in the shown process spliced sequentially one after another. The fiber pairs, one stripped optic fiber 4 of the trunk cable 3 and one stripped optic fiber 27 of one of the number of pigtails 6, are one after the other moved into the splicing position. The shown splicing device 39 is depicted without cover/housing, which is removed for each splicing operation. The end of the optic fiber 27 of the pigtail 6 and the end of a singularized optic fiber 4 of the trunk cable 3 are spliced together by electrodes 40, which generate the welding-arc. Alternatively, other welding methods like laser welding or ultra-sonic welding are possible. The shown holder 41 , which comprises at least one gripper 37, is used to hold the end of a singularized optic fiber 4 of the trunk cable 3 and the end of the optic fiber 27 of a pigtail 6. In the shown variation the holder 41 comprises separate grippers, with a first gripper for holding the end of a singularized optic fiber 4 of the trunk cable 3 and a second gripper for holding the end of the optic fiber 27 of the respective pigtail 6.

Figure 15 shows a perspective view from the back and above on the assembly station showing a second assembly step of the fiber optic fan-out assembly 1. After the splicing operation, the already spliced optic fiber 4 of the trunk cable 3 and the thereto spliced optic fiber 27 of the pigtail 6 can be routed into the housing 7. The already spliced pigtails 6 are arranged in the second cable passage 12. Once all optic fibers 4 of the trunk cable 3 are each spliced to a pigtail 6, the optic fibers 4 and thereto interconnected trunk cable 3 are arranged in the housing 7 and the trunk cable 3 is arranged in the first cable passage 8. Figure 16 shows an enlarged view of the second assembly step, the already spliced optic fiber 4 of the trunk cable 3 and the thereto spliced optic fiber 27 of the pigtails 6 are routed via the lateral recess 26 in the first 16 and/or second 17 housing part. Arranging the cable arrangement 2 in the housing 7 is typically carried out by a (semi-) automated, vision assisted and controlled, fiber insertion step, to handle and insert the cable arrangement 2 into the housing 7. The assembly station 38 typically further comprises a moving unit, which is configured for holding the pigtails 6 and moving the trunk cable 3 and the pigtails 6 with respect to each other. The second clamping means can be displaced with respect to the first clamping means along the axial direction x such that the trunk cable 3 and the pigtails 6 are moved with respect to each other by a specific distance in the axial direction x. Depending on the design, the splicing operation can be performed in an upstream assembly step or during the assembly of the cable fan-out assembly 1 .Figure 17 shows a perspective view from the back and above on the assembly station 38 showing a third assembly step of the fiber optic fan-out assembly 1. Before attaching the trunk cable 3 to the first cable passage 8 and the pigtails 6 to the second cable passage 12, the trunk cable 3 and the pigtails 6 are moved with respect to each other by a specific distance, such that the optic fibers 4 in the deflection space 10 are deflected forming a hump 11 extending in a lateral direction. The optic fibers 4 of the trunk cable 3 are attached to the first cable passage 8 and/or the pigtails 6 are attached to the second cable passage 12 by a potting compound 15. After having placed all the optic fibers 4 of the trunk cable 3 and the pigtails 6 into the housing 7 and attaching them by the potting compound 15, the housing 7 is closed and a fiber layer 22 at least wound about the optic fibers 4, 27 and the housing 7. The lateral recess 26 of the first housing part 17 is later covered by the fiber layer 22. Figure 18 shows an enlarged view of the third assembly step according to Figure 17. Similar to the first variation, the optic fibers 4 of the shown variation are also arranged in compartments 19 of the housing 7 in the transition space 9, which compartments 19 are limited by opposing partition walls 20 and/or be at least partially embedded in a potting compound 15. The shown transition space 9 and the deflection space 10 are delimited from each other by a constraint 13 by which the optic fibers 4 are positioned with respect to each other. The shown design of the housing 7, is torpedo-shaped and comprise compartments 19 in form of channels 23, which extend in the axial direction x and are arranged next to each other. LIST OF DESIGNATIONS

1 Fiber optic fan-out assem21 Cable kink protector bly 22 Fiber layer

2 Cable arrangement 25 23 Channel

3 Trunk cable 24 Outer tube

4 Optic fibers 25 Protective sleeve

5 Trunk cable sheathing 26 Recess

6 Pigtails 27 Optic fiber (pigtail)

7 Housing 30 28 Segment (trunk cable)

8 First cable passage 29 Segment (pigtail)

9 Transition space 30 Pigtail sheating

10 Deflection space 31 Slot

11 Hump 32 Fiber tray

12 Second cable passage 35 33 Slot

13 Constraint 34 Pigtail tray

14 Recess 35 End (trunk cable fiber)

15 Potting compound 36 End (pigtail fiber)

16 First housing part 37 Gripper

17 Second housing part 40 38 Assembly station

18 Splice 39 Splicing device

19 Compartment 40 Electrode

20 Partition wall

Claims

PATENT CLAIMS

1. A fiber optic fan-out assembly (1 ) comprising: a. a cable arrangement (2), comprising i. a trunk cable (3) comprising optic fibers (4) in form of a bun- die and/or at least one ribbon, preferably encompassed by a trunk cable sheathing (5); ii. a number of pigtails (6) arranged opposite to the trunk cable (3) with respect to a housing (7); b. the housing (7) extending in an axial direction (x) and encompass- ing in the axial direction (x):

- a first cable passage (8) through which the optic fibers (4) of the trunk cable (3) enter the housing (7),

- a transition space (9) through which the optic fibers (4) extend in the axial direction (x) which transition space (4) acts as integrated splice protector, and

- a deflection space (10) in which the optic fibers (4) are deflected forming at least one hump (11 ) extending in a lateral direction (y, z), - a second cable passage (12) through which the optic fibers (4) exit the housing (7) into the pigtails (6).

2. The fiber optic fan out assembly (1 ) according to claim 1 , wherein the housing (7) encompasses behind each other: i. a first cable passage (8) through which the optic fibers (4) of the trunk cable (3) enter the housing (7), ii. a transition space (9) through which the optic fibers (4) extend in the axial direction (x) which transition space (4) acts as integrated splice protector, iii. a deflection space (10) in which the optic fibers (4) are deflected forming at least one hump (11 ) extending in a lateral direction (y, z), and iv. a second cable passage (12) through which the optic fibers (4) exit the housing (7) into the pigtails (6).

3. The fiber optic fan out assembly (1 ) according to claim 1 , wherein the housing (7) encompasses behind each other: i. a first cable passage (8) through which the optic fibers (4) of the trunk cable (3) enter the housing (7), ii. a deflection space (10) in which the optic fibers (4) are deflected forming at least one hump (11 ) extending in a lateral direction (y, z), iii. a transition space (9) through which the optic fibers (4) ex- tend in the axial direction (x) which transition space (4) acts as integrated splice protector, and iv. a second cable passage (12) through which the optic fibers (4) exit the housing (7) into the pigtails (6).

4. The fiber optic fan out assembly (1) according to any one of claims 1 to 3, wherein the transition space (9) and the deflection space (10) are delimited from each other by a constraint (13) by which the optic fibers (4) are positioned with respect to each other.

5. The fiber optic fan out assembly (1) according to claim 4, wherein the constraint (13) comprises at least one recess (14) in which the optic fibers (4) are arranged in stacked manner.

6. The fiber optic fan out assembly (1 ) according to claim 4 or 5, wherein the constraint (13) comprises at least two recesses (14) arranged parallel to each other, configured to space at least two optic fibers (4) laterally apart from each other.

7. The fiber optic fan out assembly (1 ) according to any one of claims 4 to 6, wherein the constraint (13) comprises several recesses (14) arranged in a rotational symmetric manner in which the optic fibers (4) are arranged.

8. The fiber optic fan out assembly (1 ) according to any one of claims 4 to 7, wherein the constraint (13) acts as a sealing means and/or a sealing means is arranged adjacent to the constraint (13) to prevent spilling of a potting compound (15).

9. The fiber optic fan out assembly (1 ) according to any of the preceding claims, wherein the optic fibers (4) are arranged essentially parallel to each other in the transition space (9).

10. The fiber optic fan out assembly (1 ) according to claim 9, wherein the optic fibers (4) are at least partially embedded by the potting compound (15) in the transition space (9).

11 . The fiber optic fan out assembly (1 ) according to claim 9 or 10, wherein the potting compound (15) is applied when the housing (7) is partially open or closed.

12. The fiber optic fan out assembly (1 ) according to any of the preceding claims, wherein the housing (7) comprises a first housing part (16) interconnectable to a second housing part (17).

13. The fiber optic fan out assembly (1 ) according to claim 12, wherein the first housing part (16) and/or the second housing part (17) is at least partially made from an UV transparent plastic, such that a therein arranged potting compound (15) can be cured even when the housing (7) is closed.

14. The fiber optic fan out assembly (1 ) according to any one of claims 12 or 13, wherein the first and/or second housing part (16, 17) comprises with respect to the axial direction (x) a lateral recess (26) for routing the optic fibers (4) into the housing part (16, 17).

15. The fiber optic fan out assembly (1 ) according to any of the preceding claims, wherein the optic fibers (4) each comprise a splice (18) which splice is arranged in the transition space (9).

16. The fiber optic fan out assembly (1 ) according to claim 15, wherein the at least one splice (18) is arranged in a compartment (19) of the transition space (9) limited by opposing partition walls (20) of the housing (7).

17. The fiber optic fan out assembly (1 ) according to any of the preceding claims, wherein a helical cable kink protector (21 ) is attached to the first cable passage (8) of the housing (1 ) encompassing the optic fibers (4) of the trunk cable (3).

18. The fiber optic fan out assembly (1 ) according to any of the preceding claims, wherein a fiber layer (22) is at least partially wound about the optic fibers (4) and the housing (7), which fiber layer (22) is configured to act as a strain relief means between the housing (7) and the trunk cable (3).

19. A method for assembling a fiber optic fan-out assembly (1 ), comprising at least the following method steps: a. providing a housing (7) encompassing in an axial direction (x) a first cable passage (8), a transition space (9), a deflection space (10) and a second cable passage (12); b. providing a cable arrangement (2), comprising a trunk cable (3) including optic fibers (4) in form of a bundle of optic fibers (4) and/or at least one ribbon, preferably encompassed by a trunk cable sheathing (5), which optic fibers (4) extend into a number of pigtails (6); c. arranging the cable arrangement (2) in the housing (7) such that the optic fibers (4) of the trunk cable (3) enter the housing (7) through the first cable passage (8), extend across the transition space (9) and the deflection space (10) in axial direction (x) and exit the housing (7) through the second cable passage (12) into the pigtails (6); d. before attaching the optic fibers (4) both to the first cable passage (8) and the second cable passage (12), moving the trunk cable (3) and the pigtails (6) with respect to each other by a specific distance (d1 ), such that the optic fibers (4) in the deflection space (10) are deflected forming a hump (11 ) extending in a lateral direction (y, z).

20. A method for assembling a fiber optic fan-out assembly (1 ), comprising at least the following method steps: a. providing a housing (7) encompassing in an axial direction (x) a first cable passage (8)and a second cable passage (12); b. providing a trunk cable (3) including optic fibers (4) in form of a bundle of optic fibers (4) and/or at least one ribbon, preferably encompassed by a trunk cable sheathing (5); c. providing a number of pigtails (6), each of the pigtails (6) comprising an optic fiber (27); d. splicing the optic fiber (27) of one of the number of pigtails (6) to one of the optic fibers (4) of the trunk cable (3); e. placing the optic fiber (27) of the pigtail (6) spliced to one of the optic fibers (4) of the trunk cable (3) into the housing (7), such that the optic fiber (27) of the pigtail (6) extends in axial direction (x) and exits the housing (7) through the second cable passage (12) into the pigtail (6); f. repeating steps d. and e. until all of the optic fibers (27) of the number of pigtails (6) are spliced to optic fibers (4) of the trunk cable (3) and placed into the housing (7).

21 . The method according to claim 20, wherein the housing (7), in the axial di- rection (x), additionally encompasses a transition space (9) and/or a deflection space (10).

22. The method according to one of claims 20 and 21 , further comprising the step of placing the trunk cable (3) into the housing (7), such that trunk cable (3) enters the housing (7) through the first cable passage (8), wherein this step is preferably conducted either after step b. or f.

23. The method according to one of claims 21 and 22, further comprising the step of, before attaching the optic fibers (4) both to the first cable passage (8) and the second cable passage (12), moving the trunk cable (3) and the pigtails (6) with respect to each other by a specific distance (d1 ), such that the optic fibers (4) in the deflection space (10) are deflected forming a hump (11 ) extending in a lateral direction (y, z).

24. Method according to one of claims 20 to 23, wherein, during steps d. to f., unspliced optic fibers (4) and pigtails (6) remain outside the housing (7).

25. Method according to claim 24, wherein the already spliced optic fiber (4) of the trunk cable (3) and the thereto spliced optic fiber (27) of the pigtail (6) is routed into the housing (7) via a lateral recess (26) in the first and/or second housing part (16, 17).

26. Method according to any of claims 20 to 25, wherein a segment (28) of the trunk cable sheating (5) and/or a segment (29) of a pigtail sheating (30) are stripped before the splicing operation.

27. Method according to any of claims 20 to 26, wherein the optic fibers (4) of the trunk cable (3) are singularized and each optic fiber (4) is placed in a respective slot (31 ) of a fiber tray (32) and/or the pigtails (6) are singularized and each pigtail (6) is placed in a respective slot (33) of a pigtail tray (34) before the splicing operation.

28. Method according to claim 27, wherein an end (35) of a singularized optic fiber (4) of the trunk cable (3) and an end (36) of the optic fiber (27) of a singularized pigtail (6) are aligned with each other and spliced with each other, preferably by fusion splicing.

29. Method according to any one of claims 27 or 28, wherein the singularized optic fiber (4) of the trunk cable (3) and the singularized optic fiber (27) of the pigtail (6) are during the splicing operation each held in position by a gripper (37).

30. Method according to any one of claims 20 to 29, wherein after placing all the optic fibers (4) of the trunk cable (3) and the pigtails (6) into the housing (7), the optic fibers (4) of the trunk cable (3) are attached to the first cable passage (8) and/or the pigtails (6) are attached to the second cable passage (12) by a potting compound (15).

31. Method according to any one of claims 20 to 30, wherein after placing all the optic fibers (4) of the trunk cable (3) and the pigtails (6) into the housing (7), the hosing (7) is closed and a fiber layer (22) is at least partially wound about the optic fibers (4) and the housing (7).

32. The method according to claim 19 to 31 , wherein the housing (7) encompasses behind each other a first cable passage (8), a transition space (9), a deflection space (10) and a second cable passage (12), such that the optic fibers (4) of the trunk cable (3) enter the housing (7) through the first cable passage (8), extend across the transition space (9) and the deflection space (10) in axial direction (x) and exit the housing (7) through the second cable passage (12) into the pigtails (6).

33. The method according to claim 19 to 32, wherein the housing (7) encompasses behind each other a first cable passage (8), a deflection space (10), a transition space (9), and a second cable passage (12), such that the optic fibers (4) of the trunk cable (3) enter the housing (7) through the first cable passage (8), extend across the deflection space (10) and the transition space (9) and in axial direction (x) and exit the housing (7) through the second cable passage (12) into the pigtails (6).