JP2010066474A - Optical connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical connection structure, capable of positioning the end of an optical fiber with ease and high accuracy, without occupying a large space on a substrate, even when connecting the optical fiber disposed on the substrate in parallel, with the substrate to a light-emitting/receiving element mounted so that the optical axis faces a vertical direction, with respect to the substrate. <P>SOLUTION: The structure comprises at least an optical fiber, having a tip abraded at an angle of 45° and bent in an S-shape, and the light-emitting/receiving element connected/fixed electrically so that the optical axis is made to face the vertical direction, with respect to the substrate. The optical fiber whose tip is bent in the S-shape is mounted so that the abraded end covers the light-emitting/receiving element, and the end of the optical fiber whose tip is bent into an S-shape is aligned to a light-emitting/receiving part of the light-emitting/receiving element. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical connection structure for connecting an optical fiber to a light emitting / receiving element.

  Conventionally, an optical connection structure having an optical fiber is used to connect optical functional components on a substrate. In the optical connection structure, an optical fiber having a connection point opened in a direction perpendicular to the substrate, which is connected in parallel to the substrate, such as attaching an optical fiber to the ferrule and butting the optical functional component along the substrate Some components are connected in a vertical direction to a substrate such that the tip of the optical fiber is cut obliquely and brought into contact with the component.

  In an optical connection structure for connecting in parallel with a substrate, an optical connector having a housing or a ferrule is generally used, and stable connection can be achieved by positioning and butting. However, there is a problem that the housing and the ferrule occupy a large space on the substrate.

  In addition, in the optical connection structure that connects to the substrate in the vertical direction, active alignment is performed to align the optical fiber while irradiating light from the laser. However, high accuracy is required, so it is easy and stable. It is difficult to connect, and for example, the optical functional component may be damaged when the optical functional component contacts the optical fiber.

  Although it is possible to optically connect non-contact using a reflective layer such as a lens, the number of components increases, and the time required for connection increases due to the alignment of the reflective layer with optical functional components and optical fibers. There has been a problem of cost (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 9-026515

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a light emitting / receiving element mounted so that the optical axis is perpendicular to the substrate, on the substrate. Even when connecting optical fibers arranged parallel to the substrate, an optical connection structure that can easily and accurately position the end of the optical fiber without occupying a large space on the substrate is provided. There is to do.

  The optical connection structure of the present invention includes at least a tip S-shaped bent optical fiber whose tip is polished at 45 °, and a light emitting / receiving element electrically connected and fixed so that the optical axis is perpendicular to the substrate. The tip S-shaped bent optical fiber is mounted so that the polished end covers the light receiving / emitting element, and the end of the tip S-shaped bent optical fiber is positioned at the light receiving / emitting portion of the light receiving / emitting element. It is characterized by being combined.

  In the present invention, the optical fiber fixing member further includes an optical fiber fixing member that supports the tip portion of the S-shaped bent optical fiber so as to align with the light emitting / receiving portion of the light emitting / receiving element. It is preferable to fix the S-shaped bent optical fiber parallel to the substrate.

  According to the optical connection structure of the present invention, when an optical fiber disposed parallel to the substrate on the substrate is connected to the light receiving and emitting element mounted so that the optical axis is perpendicular to the substrate However, since the optical fiber can be directly positioned on the substrate without using other members, the end position of the optical fiber can be aligned with high precision and ease, and the connection stability is high. In the thickness direction, the optical fiber is bent by the thickness of the light emitting / receiving element, and does not occupy a large space. Therefore, an effect that the degree of freedom of the input / output position of the optical fiber is high can be obtained.

Next, an embodiment of the optical connection structure of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a view showing an embodiment of the optical connection structure of the present invention. As shown in FIG. 1, the optical connection structure of the present invention is an optical fiber 1 whose tip is bent into an S-shape, and light receiving and emitting light fixed so that its optical axis is perpendicular to the substrate 2. It is comprised from the element 3.

  It is essential that the optical fiber 1 in the optical connection structure of the present invention has its tip bent into an S shape and polished at 45 °. Here, the S-shaped bending of the optical fiber in the present invention means that the tip of the optical fiber is bent by the thickness of the light emitting / receiving element. According to such a configuration, the optical fiber 1 is bent in the thickness direction of the substrate 2 by the thickness of the light emitting / receiving element 3 and the tip is polished by 45 °, so that the optical axis is perpendicular to the substrate. An optical fiber wired in parallel to the substrate on the substrate can be aligned with the light emitting / receiving element mounted so as to face with high accuracy and easily.

  Furthermore, in the present invention, since it is directly disposed on the optical fiber without using other members, the stability of the connection can be increased. In the present invention, since the optical fiber is bent in the thickness direction of the substrate by the thickness of the light emitting / receiving element, a connection structure can be formed without occupying a large space on the substrate. With this compact structure, the degree of freedom of the input / output position of the optical fiber can be increased.

  The optical fiber in the present invention may be a single-core optical fiber or a tape core obtained by tapeting a plurality of optical fibers with a resin or the like, and the number of optical fibers connected at one time. There is no limit. Such an optical fiber can be appropriately selected according to the application, but in the present invention, it is preferably a quartz optical fiber, and further, formed by plastically deforming an optical fiber material. It is preferable that Further, the refractive index distribution in the optical fiber can be appropriately selected depending on the purpose of use, such as a step distribution and a crazed distribution.

  Furthermore, in the present invention, as shown in FIG. 2, it is preferable to include an optical fiber fixing member 4. The optical fiber fixing member 4 supports the tip of the S-shaped bent optical fiber 1 so that the tip of the S-shaped bent optical fiber 1 is aligned with the light emitting / receiving portion of the light emitting / receiving element, and the tip S-shaped bent optical fiber 1 is parallel to the substrate 2. It is a member fixed to. According to this optical fiber fixing member, the end of the optical fiber 1 can be easily aligned with the light emitting / receiving portion of the light emitting / receiving element 4 with high accuracy.

  Moreover, in this invention, it is preferable to provide a V groove or a through-hole in the side surface which supports and fixes the optical fiber 1 of the optical fiber fixing member 4. By aligning the optical fiber 1 while accommodating the optical fiber 1 in this V-groove or through-hole, the alignment accuracy of the optical fiber 1 with respect to the width direction of the optical fiber fixing member 4 can be improved.

  The material used for the substrate and the optical fiber fixing member in the present invention is appropriately selected depending on the material of the optical fiber to be connected, the required strength and alignment accuracy, and in particular, plastic, ceramic, Those made of metal or the like are preferably used. As the plastic material, a crystalline polymer, an amorphous polymer, a composite material, or the like can be used. As the crystalline polymer, PPS (polyphenyl sulfide), PEEK (polyether ether ketone) and the like are preferable. As the amorphous polymer, a liquid crystal polymer and the like are preferable. As the composite material, a glass-mixed epoxy material and the like are used. preferable. The plastic material is preferably one that can withstand the rice field reflow. The optical connection structure in the present invention can be used upside down depending on the layout of the light emitting / receiving element and the optical fiber, and the installation direction of the substrate is not particularly limited.

  Furthermore, in the present invention, it is preferable to interpose a refractive index matching material between the tip of the optical fiber and the light emitting / receiving portion of the light emitting / receiving element. As the refractive index matching material, a material appropriately selected according to the environmental conditions, the manufacturing process and the like in which the optical connection structure of the present invention is used can be used. The refractive index matching material may be liquid or solid, and may be, for example, oil, grease, gel, or film.

  Further, the optical connection structure of the present invention as described above is configured to drive the light emitting / receiving element 3 and the light emitting / receiving element 3 connected to the S-shaped bent optical fiber 1 on the substrate 2 as shown in FIG. It can also be suitably applied to an optical transmission module on which the light emitting / receiving element driving IC chip 5 is mounted. The optical transmission module shown here is an embodiment in which the optical fiber 1 is fixed by the optical fiber fixing member 4 and the ball grid array is provided on the substrate 2. However, the optical transmission module can be applied to the present invention. The transmission module is not limited to this.

<Example 1>
A 4-fiber ribbon (quartz multimode optical fiber, core: graded index 50 microns, manufactured by Sumitomo Electric) is used as the optical fiber, and a multimode 1 × 4 VCSEL array (manufactured by Optowell, wavelength 850 nm) is used as the light emitting / receiving element. ) Was used to produce an optical connection structure having the configuration shown in FIG. The optical fiber is bent in the opposite direction twice using a gas burner with a radius of curvature of 1 mm and a bending angle of 30 ° to form an S-shape.

<Example 2>
An optical connection structure having the configuration shown in FIG. 2 was produced in the same manner as in Example 1 except that the same optical fiber and light emitting / receiving element as those in Example 1 were used and an optical fiber fixing member was used. As shown in FIG. 4, the optical fiber fixing member 4 is made of PPS (polyphenyl sulfide) having an alignment V groove having a V-shaped angle of 60 °, and the optical fiber 1 is formed into a V groove. When fixed inside, the protruding amount of the side surface of the optical fiber was 5 μm.

<Example 3>
FIG. 5 shows the same optical fiber and light emitting / receiving element as in Example 1 except that a through hole 6 is provided in the substrate and optical fiber fixing members 4 are provided on both sides of the substrate. An optical connection structure having the structure shown was produced. As shown in the figure, the optical fiber can be guided to the back of the substrate by passing through the through hole 6 by S-bending. As shown in FIG. 4, both optical fiber fixing members 4 are made of PPS (polyphenyl sulfide) having an alignment V groove with a V-shaped angle of 60 °, and the optical fiber 1 is made of V When fixed in the groove, the protruding amount of the side surface of the optical fiber was 5 μm.

  As a result of producing five sets of the optical connection structures of the examples as described above, the connection loss in the optical connection structures of Examples 1 to 3 is 1.8 dB, 1.6 dB, and 1.7 dB for each optical fiber average. The average variation for each connection was 0.5 dB, 0.3 dB, and 0.35 dB. Thus, it was shown that the connection loss is suitably reduced in the optical connection structure of the present invention. Further, in Example 3, the optical fiber on the upper surface of the substrate could be wired on the lower surface, and the degree of freedom of the optical fiber wiring could be verified.

It is the figure which showed one Embodiment of the optical connection structure of this invention. It is the figure which showed other embodiment of the optical connection structure of this invention. It is the figure which showed embodiment of the optical transmission module using the optical connection structure of this invention. It is the figure which showed the V groove for position alignment of the optical fiber fixing member in this invention. It is the figure which showed other embodiment of the optical connection structure of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical fiber, 2 ... Board | substrate, 3 ... Light emitting / receiving element, 4 ... Optical fiber fixing member,
5 ... IC chip for light emitting / receiving element driving, 6 ... through hole.

Claims (5)

At least a tip S-shaped bent optical fiber having a tip polished to 45 °;
It consists of light receiving and emitting elements that are electrically connected and fixed so that the optical axis is perpendicular to the substrate.
The tip S-shaped bent optical fiber is mounted such that a polished end covers the light emitting / receiving element,
An optical connection structure, wherein an end of the S-shaped bent optical fiber is aligned with a light receiving / emitting portion of the light receiving / emitting element. An optical fiber fixing member;
The optical fiber fixing member supports the tip of the S-shaped bent optical fiber so that the tip of the S-shaped bent optical fiber is aligned with the light emitting / receiving portion of the light emitting / receiving element, and the tip S-shaped bent optical fiber is parallel to the substrate. The optical connection structure according to claim 1, wherein the optical connection structure is fixed to the optical connection structure.   3. The optical fiber fixing member according to claim 1, wherein the optical fiber fixing member has a V-groove or a through hole on a side surface for supporting and fixing the optical fiber, and the optical fiber fixing member is aligned while accommodating the optical fiber therein. The optical connection structure described.   The optical connection structure according to claim 1, wherein the bent portion of the distal S-shaped bent optical fiber is formed by plastic deformation of an optical fiber material.   5. An optical transmission module comprising a light emitting / receiving element connected to an optical fiber by the optical connection structure according to claim 1 and an IC chip for driving the light receiving / emitting element.

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