JPS62211605A - Submarine optical repeater housing - Google Patents

Abstract

PURPOSE:To contrive improvement of the connection workability and the reliability, and to realize miniaturization of the titled repeater housing by executing the final connection of a submarine optical cable and a submarine optical repeater circuit, by a lens connector which has been provided on a feedthrough part. CONSTITUTION:An optical lens 19 is connected to the tip of an optical fiber which has been connected by an assembly cable 10 which becomes a feeding line to a submarine optical repeater circuit 12, and an optical assembly cable 11 which becomes an optical signal line, and also, an optical lens 23 is connected to the tip of an optical fiber 22 which has been led out of a submarine optical cable, and a pressure tight and airtight structure by solder is performed to the lens 19. The circuit 12 and the submarine optical cable are connected by forming then integrally in one body with a feedthrough 8 or an optical feedthrough 8a, or providing adjacently an optical connector part 15, or a light and feed connector part 16, and butting the end faces of the lens 19 and 23. As a result, the time required for connecting the cable and the repeater is shortened, and the surplus length of the fiber is shortened, therefore, a rupture accident caused by bending is obviated, and the reliability of a transmission line is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a submarine optical repeater housing which is small in size and has excellent connection workability and reliability.

(Prior art and its problems) Figure 1(a) shows a conventional submarine optical repeater housing,
1 is a submarine optical cable, 2 is a submarine optical cable retention device, 3
is a universal joint part, 4 is a tail cable connection part, 5 is a tail cable, 7 is an end plate, 8 is a feedthrough, 10 is a feeder assembly cable, 11 is an optical assembly cable,
12 is a submarine optical repeater circuit, 13 is a pressure-resistant cylinder, and 14 is a cushion.

Because of this structure, electrical and optical connections between the submarine optical cable 1 and the submarine optical repeater circuit 12 are made by connecting the tail cable 5 to the tail cable connection part 4.

Achieve by connecting with each other. Here, the tail cable 5 is
The basic structure is a pressure-resistant metal shell that houses multiple optical fibers and is covered with insulating polyethylene. Therefore, when connecting the tail cable connection part 4, three steps are required: (a) fusion splicing of optical fibers to each other, (o) connection of pressure-resistant metal shells, and (c) welding of polyethylene. There was a drawback that the entire process required an extremely long time, approximately 8 hours.

Furthermore, in order to connect the tail cable at the position shown in FIG. 1(a), the tail cables 5 on both sides are pulled out of the submarine optical repeater housing and attached to the optical fiber fusion splicing device. Each requires an extra length of about 1 -, and a space is essential inside the housing to accommodate this extra length after the connection is completed.

Therefore, there was also a drawback that the size of the housing was large.

FIG. 1(b) shows another example of a conventional submarine optical repeater housing, in which 4a is an optical fiber connection part, 4b is a pressure-resistant housing, and 4c is a polyethylene coating.

In the example shown in this figure, the extra length necessary for fusion-splicing the fibers with each other at the optical fiber connection portion 4a is housed inside the pressure-resistant housing 4b, and the entire outer periphery is insulated with a large polyethylene coating 4C. In such a structure, it particularly takes a long time to weld the polyethylene coating 4C, and the inspection area for confirming reliability is also large, resulting in poor workability. The overall length of the submarine optical repeater housing is increased to accommodate the extra length, which is the same as the conditions in Figure 1 (al).

(Objective of the Invention) The object of the present invention is to improve connection workability and reliability by using a structure in which the final connection between the submarine optical cable and the submarine optical repeater circuit is made by a lens connector provided in the feedthrough section. Another object of the present invention is to provide a submarine optical repeater housing that is miniaturized.

(Features of the Invention) The present invention provides a submarine optical repeater housing in which lenses are connected to the tips of the optical fibers connected to the submarine optical repeater circuit and the optical fibers led out from the submarine optical cable. The circuit side lens has a pressure-resistant and airtight structure, and the end faces of both the submarine optical repeater circuit side lens and the submarine optical cable side lens are brought into contact with each other to optically connect the submarine optical repeater circuit and the submarine optical cable. Main characteristics.

In the conventional technology, a pressure-resistant and air-tight structure is applied around the optical fiber, whereas in the present invention, a pressure-resistant and air-tight structure is applied to the submarine optical repeater side lens. In addition, conventional fusion splicing requires an extra connection length of about 1n+ for both optical fibers to be connected, but since the present invention uses a connector type connection, only a few extra connections are sufficient. are different.

Furthermore, here, the diameter of the light wavefront propagating within the thin fiber core, which is originally 10 μm, is expanded by a factor of 100 or more using a lens, and then the fibers are interconnected. Therefore, even with the most precise processing technology, there still remain processing errors on the order of 0.1 μm, as well as temperature changes during operation.

Connecting optical loss caused by misalignment of the abutting surfaces due to vibration or the like can be significantly suppressed compared to conventional connectors in which fiber cores are directly abutted.

Such a lens connector is particularly suitable for application to submarine transmission lines that require extremely low loss and stability over a long period of 25 years.

(Example) Examples of the present invention will be described in detail below.

FIG. 2 is a diagram illustrating an outline of an embodiment of the present invention, and FIG. An overview of an embodiment of the invention described in claim 2 is shown.

In these figures, 6 is a feeder tail cable, 6a is an optical tail cable, 8a is an optical feedthrough, 9 is a feeder feedthrough, 10 is a feeder assembly cable, and 11
1 is an optical assembly cable, 15 is an optical connector section, and 16 is an optical/power supply connector section. As shown in the figure, since the optical connector part 15 or the optical/power supply connector part 16 is provided adjacent to or integrally with the feedthrough 8 or the optical feedthrough 8a, first, the fiber on the cable side and the fiber of the repeater circuit are connected to each other. can be connected with a connector.

Therefore, the connection work becomes easy, and only a small amount of extra fiber length is required on the cable side for connection, and therefore, the space for storing the extra length is also very small.

If the cable retention device 2 and the pressure cylinder 13 are directly connected without any bends as shown in FIG. 2 (al), it is possible to isolate the space accommodating the tail cable from external pressure. It is not necessary to protect the optical fiber with pressure resistance, and a simple structure can be used in which the optical fiber core is used as an optical tail cable.In this case,
The feeder tail cable 6 and its feedthrough 9 may be coated separately. On the other hand, when connecting the cable anchoring device 2 and the pressure-resistant cylinder 13 via the bending part 3 as shown in Fig. 2, the tail cable accommodation time cannot be fused from external pressure, so the optical fiber is Must be pressure protected. Therefore, it is efficient to use the metal pipe used for voltage protection as a power supply path. Therefore, in this case, it is effective to use the tail cable 5 that also serves as a signal (optical fiber) power supply. In this case as well, if the optical/power supply connector section 16 is installed adjacent to or integrally with the feedthrough 8, the remaining length of the tail cable 5 can be shortened, and as a result, the joint ring 13a is This makes it possible to shorten the overall length of the submarine optical repeater casing.

Figure 3 shows the optical/power supply connector section 16 shown in Figure 2(b).
and a detailed view of one embodiment of the feedthrough 8,
18 is a tail cable, 18 is an optical signal introduction hole, 19 is an optical lens (A), 20 is an airtight joint of the optical lens (A) by soldering, 10 is a power feed line assembly cable that serves as a power feed path to the repeater circuit, 11 2 is an optical assembly cable that also serves as an optical signal path, 22 is an optical fiber from a submarine optical cable, 23 is an optical lens (B), 24 is a lens guide mechanism, 25 is a pressure-resistant metal shell (A), and 26 is an insulating polyethylene layer (A). ), 27 is the pressure-resistant pipe of the tail cable, 28 is the pressure-resistant metal shell (B), 29 is the insulating polyethylene layer (B), 3
0 is pressure-resistant connection structure, 31 is polyethylene connection structure, 32
3 is a holding part, and 33 is a taper seal.

In this way, by employing a structure in which a lens is used in the feedthrough portion and a connector is connected, the following advantages can be expected.

(11 Feedsle has a structure in which the periphery of the lens is hermetically sealed, so it can be expected to have long-term stability compared to a structure in which the fragile optical fiber is directly sealed as in the conventional technology. When water pressure is applied to the through part,
The lens (A) 19 has the advantage of being geometrically blocked by the opening of the fiber introduction hole, which is narrower than the outer diameter of the lens (A) 19, against the inward pushing force, and the gap between the lens and the peripheral area is kept airtight. It is sufficient to fill it to keep it watertight.

On the other hand, the fiber direct sealing type requires a mechanical holding force to maintain airtightness and watertightness and at the same time to resist the force of pushing the fiber in by water pressure. The structure that directly achieves two different types of performance, airtightness, watertightness, and mechanical retention force, on the outer periphery of a fragile, small-diameter fiber is extremely fine and complex, and it is difficult to maintain its performance over a long period of time. It is difficult to maintain stability.

(2) Optical connections are made using connectors, which improves workability compared to conventional fusion splicing.Furthermore, the extra length of the fiber can be extremely short, so the housing can be made smaller by reducing storage space. . Since it is possible to avoid bending the fiber close to the limit due to storing the excess length, it can also contribute to improving the reliability of the transmission line.

(3) Since a lens type connector is used, the wavefront of the light is enlarged using a lens with an outer diameter of several millimeters and compared to direct butting together of thin fibers with a core diameter of about 10 μm.

Therefore, there is less connection loss due to axis misalignment. That is, even with the most precise processing technology, it is possible to effectively suppress the connection optical loss caused by the remaining axis misalignment on the order of 0.1 micron.

In addition, regarding the invention stated in claim 1, claim 3
The pressure-resistant structure (25, 2B) in the embodiment shown in the figure.

30) and the insulating structure (26, 29, 31) may be omitted, and the feeder feedthrough 9 may be provided separately. This allows for insulation
.

Polyethylene molding is easy and can be done on a small scale.

In other words, since the molding is carried out locally at the connection part of the power supply line, there is no need for optical fibers that are sensitive to thermal history to be present near or inside the connection part, making it safe, and the design also reduces the total amount of polyethylene that melts during molding. Therefore, there are advantages such as being able to shorten the time required for molding.

(Effects of the Invention) As explained above, the present invention provides a lens for obtaining water pressure strength, airtightness, and watertightness for a long period of 25 years under water depths of up to 8000 m in a submarine optical repeater housing. It has a feedthrough structure that is fitted into the end plate like a window to seal the gap, and the lens attached to the end of the fiber on the cable side is fitted to this lens, which provides high reliability and eliminates connection optical loss due to processing errors. The time required for optical connection between a cable and a repeater can be reduced from more than an hour (in the case of 6-pair connection) to several minutes. In addition, the extra fiber length (approximately 2 m), which is essential for conventional fusion splicing, can be significantly shortened to a few centimeters due to the connector connection, which saves storage space for the extra fiber and reduces the extra length of the housing by more than 20%. can be shortened. In addition, since it is possible to eliminate the possibility of stochastic fiber breakage due to fiber bending caused by storing a long excess length in a narrow space, it is possible to improve the long-term stability of the transmission line. There are many great benefits in many areas.

[Brief explanation of drawings]

Figure 1 (al is a schematic vertical cross-sectional view showing the housing side of a conventional flexible submarine optical repeater; Figure 1 (b) is a vertical cross-sectional view showing the housing side of a conventional rigid submarine optical repeater; Figure 2 (a) is a longitudinal cross-sectional view showing an embodiment of the first invention of the present application, Fig. 2(a) is a longitudinal cross-sectional view showing an embodiment of the second invention of the present application,
The figure is a longitudinal cross-sectional view showing a part of the detailed structure of the embodiment shown in FIG. 2(b). DESCRIPTION OF SYMBOLS 1... Submarine optical cable, 2... Submarine optical cable retention device, 3... Universal joint part, 4... Tail cable connection part, 4a... Optical fiber connection part, 4b.
...Pressure housing, 4c...polyethylene coating,
5... Tail cable, 6... Power supply tail cable, 6a... Optical tail cable, 7... End plate, 8... Feedsle, 8a... Optical feedsle, 9... Supply Electric wire feedthrough, 10...
Power feed line assembly cable, 11... Optical assembly cable, 12... Submarine optical repeater circuit, 13...
・Pressure cylinder, 14... cushion, 15...
・Optical connector part, 16... Optical/power supply connector part,
18... Optical signal introduction hole, 19... Optical lens (A
), 20... Airtight joint part, 22... Optical fiber, 23... Optical lens (B), 24... Lens guide mechanism, 25... Pressure-resistant metal shell (A), 26
... Insulated polyethylene layer (A), 27... Pressure-resistant pipe, 28... Pressure-resistant metal shell (B), 29... Insulated polyethylene layer (B), 30... Voltage-resistant connection structure, 3
1... Polyethylene connection structure, 32... Holding part, 33... Taper seal.

Claims (2)

[Claims] (1) Store the submarine optical repeater circuit in a pressure-resistant and airtight manner,
In a submarine optical repeater housing electrically, mechanically, and optically connected to a submarine optical cable, at least one optical signal introduction hole provided in a pressure-resistant cylinder end plate of the submarine optical repeater housing is provided. 1 optical lens is water pressure resistant,
one lens that is attached in an airtight manner and to which at least one first optical fiber connected to the submarine optical repeater circuit is connected in advance to each of the first optical lenses; On the other hand, each optical fiber end led out from the submarine optical cable anchoring device provided at the end of the submarine optical cable also has a termination portion to which a second optical lens is individually connected, and the lens type A submarine optical repeater housing comprising a lens guide mechanism that optically connects an end surface of the first optical lens of the feedthrough and an end surface of the second optical lens of the termination section. (2) Store the submarine optical repeater circuit in a pressure-resistant and airtight manner,
In a submarine optical repeater housing electrically, mechanically, and optically connected to a submarine optical cable, at least one optical signal introduction hole provided in a pressure-resistant cylinder end plate of the submarine optical repeater housing is provided. 1 optical lens is water pressure resistant,
one lens that is attached in an airtight manner and to which at least one first optical fiber connected to the submarine optical repeater circuit is connected in advance to each of the first optical lenses; On the other hand, each optical fiber end led out from the submarine optical cable anchoring device provided at the end of the submarine optical cable also has a termination portion to which a second optical lens is individually connected, and the lens type The lens type feed through has a lens guide mechanism that optically connects the end face of the first optical lens of the feed through and the end face of the second optical lens of the termination section, and the lens type feed through has a The end plate is attached to the end plate via a first pressure-resistant metal shell containing an optical lens and a first insulating polyethylene layer on the outer periphery, while the termination portion of the optical fiber on the submarine optical cable tensioning device side is attached to the second
An optical lens and an optical fiber connected to the second optical lens are enclosed in a second pressure-resistant metal shell that is continuous from the pressure-resistant pipe of the submarine optical cable, and the outer periphery of the second pressure-resistant metal shell is surrounded by the submarine optical cable. A second insulating polyethylene layer that is continuous with the insulating polyethylene layer is applied, and includes a connecting portion between the first optical lens and the second optical lens, and is connected to the first pressure-resistant metal shell and the second pressure-resistant metal shell. It is characterized by having a connection structure for mutually connecting the first insulating polyethylene layer and the second insulating polyethylene layer while maintaining a withstand voltage, and further having a connection structure for seamlessly welding the end faces of the first insulating polyethylene layer and the second insulating polyethylene layer to each other. Submarine optical repeater housing.