JP5282988B2 - Optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical connector that easily forms an internal reflecting surface in the optical connector for performing optical path conversion by an internal reflection system. <P>SOLUTION: An optical connector main body 6 that is a resin molding formed of light transmissive resin includes: an optical fiber inserting hole 11 parallel with a substrate surface 3a; an optical fiber abutting surface 12a disposed at the forward side of the optical fiber inserting hole 11; and an internal reflecting surface 15a disposed at the forward side close to the optical fiber abutting surface 12a. The internal reflecting surface 15a is formed by a bottom surface of a bottomed hole 15 bored in the optical connector main body 6 from an outer surface thereof in a direction intersecting with an extension direction of each optical fiber at an angle less than 90&deg; and bored toward the forward position very close to the optical fiber abutting surface 12a, respectively. In a metallic mold for resin-molding the optical connector main body 6, the internal reflecting surface 15a can be formed by a core pin for forming the bottomed hole 15. By changing the core pin, the internal reflecting surface 15a desired can be freely formed. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention is based on internal reflection between an optical axis of an optical fiber introduced into the optical connector body in parallel with a first optical path, for example, a substrate surface, and an optical axis of a second optical path, for example, an optical element. The present invention relates to an optical connector that performs optical path conversion to couple these optical axes.

As an optical connector for inputting / outputting optical signals between an optical fiber and an optical element on a circuit board, an optical path is changed by internal reflection between the optical fiber introduced in parallel with the substrate surface and the optical element. There are optical connectors that input and output optical signals (Patent Document 1, Patent Document 2). Here, the internal reflection refers to reflection in which light incident on the transparent body is reflected on the boundary surface with the outside (boundary surface with air or the like) without passing through the transparent body.
As shown in FIG. 14, the optical connector (optical element module) 71 of Patent Document 1 has a right triangle shape having a 45 ° inclined surface 75 a and a vertical surface 75 b perpendicular to the circuit board 73 on a transparent structure 76. The protrusion 75 is formed, and the optical fiber 74 is abutted against the vertical surface 75b of the protrusion 75. The slope 75a of the protrusion 75 serves as an internal reflection surface (also indicated as 75a when referred to as an internal reflection surface). Reference numeral 74a denotes an optical fiber core.
In this optical connector 71, the light emitted from the tip of the optical fiber 74 enters the protrusion 75 from the vertical surface 75b of the protrusion 75, and is reflected (internally reflected) by the slope of the protrusion 75, that is, the internal reflection surface 75a. The optical path is changed to a right angle downward and enters the optical element 72 on the circuit board 73. The light emitted from the optical element 72 enters the optical fiber 74 through the reverse optical path.

The optical connector disclosed in Patent Document 2 has a bottom hole for an optical fiber formed parallel to a circuit board in an optical connector body made of a transparent material, and the tip of the optical fiber inserted and fixed in the bottom hole for the optical fiber. In this configuration, a recess having a slope of 45 ° is formed in front of the part. The 45 ° slope is an internal reflection surface.
In this optical connector, the light emitted from the tip of the optical fiber is reflected (internally reflected) on the inclined surface, converted into an optical path at a right angle downward, and enters the optical element on the circuit board.
JP 2001-174671, FIG. 1B, etc. JP 2007-121973, FIG. 1 etc.

  Each of the above conventional optical connectors has a structure that changes the optical path by an internal reflection method, and an inclined surface is provided in front of the tip of the optical fiber parallel to the circuit board as an internal reflection surface. Each of the slopes (internal reflection surface) for changing the optical path is a projection of the transparent structure or a wide surface of the optical connector body.

By the way, the slope for optical path conversion by internal reflection may be a flat surface if only a simple optical path conversion action is required.
However, in order to increase the light coupling efficiency, it is necessary to have a light condensing function as well as an optical path changing function.
In that case, a curved surface that collects light may be formed at a position facing the tip of the optical fiber on the inclined surface (see FIG. 2 of Patent Document 1).
However, in a structure in which the outer surface of the transparent structure or the optical connector main body is directly inclined as in the conventional optical connector, it is not easy to form a minute curved surface that collects light for each optical path of each optical fiber. That is, when a transparent structure or an optical connector main body is resin-molded, it is necessary to form a large number of minute curved surfaces (for example, a rotating parabolic surface) on one side surface of the mold, so that it is not easy to manufacture the mold.

  The present invention has been made to eliminate the above-mentioned conventional drawbacks. In the case of adopting an internal reflection method in an optical connector that changes the optical path in the connector, an internal reflection surface that mainly performs a light collecting function is formed. An object of the present invention is to provide an optical connector that is easy to implement.

According to the present invention for solving the above-described problems, a plurality of first optical paths on the optical fiber side inserted into an optical fiber insertion hole formed in parallel with an upper surface of a circuit board on which an optical element is mounted by internal reflection, and each of the first optical paths. An optical connector that couples a plurality of second optical paths on the optical element side that respectively intersect the optical paths of
The optical connector body is a resin molded product,
The rear of the optical fiber insertion hole is an optical fiber introduction opening that opens to the rear of the optical connector body, and a hollow portion that is filled with an adhesive that opens to the top of the optical connector body,
In front of the optical fiber insertion hole, a recess is formed that opens above the optical connector body and can be filled with an adhesive, and the front of the insertion hole in the recess is an abutting surface of the optical fiber. ,
The optical connector body has an internal reflection surface in the optical connector body in front of the optical fiber insertion hole,
The resin between the optical fiber insertion hole and the internal reflection surface, and the internal reflection surface and the optical element is transparent,
The internal reflection surface is opened from the outer surface to the optical connector main body for each optical fiber in a direction that intersects each optical fiber extension direction at an angle of less than 90 ° and to a position in front of the optical fiber abutting surface. The bottom surface of the bottomed hole is symmetrical with respect to the axis of the bottomed hole,
The optical fiber and the optical element are optically coupled by the internal reflection surface.

  According to a second aspect of the present invention, in the optical connector according to the first aspect, the bottomed hole is formed in the optical connector main body from an inclined outer surface inclined at an angle of less than 90 degrees with respect to a surface orthogonal to the optical fiber extension direction. It is characterized by being.

  According to a third aspect of the present invention, in the optical connector of the first or second aspect, the bottom surface of the bottomed hole is a flat surface or a curved surface convex toward the hole opening side.

  According to a fourth aspect of the present invention, there is provided the optical connector according to the third aspect, wherein when the bottom surface of the bottomed hole is a flat surface, a lens portion that collects light is formed on an input / output surface of the connector main body with respect to the optical element on the circuit board. It is characterized by that.

  According to a fifth aspect of the present invention, in the optical connector according to the third aspect, when the bottom surface of the bottomed hole is a curved surface convex toward the hole opening side, the input / output surface of the connector main body with respect to the optical element on the circuit board is made flat. It is characterized by that.

  According to a sixth aspect of the present invention, in the optical connector according to any one of the first to fifth aspects, an optical fiber guide groove for guiding the optical fiber is formed at the bottom of the recess.

According to the present invention, the internal reflection surface for converting the optical path is formed on the bottom surface of the bottomed hole opened from the outer surface of the optical connector body, so that the outer surface itself of the optical connector body is the internal reflection surface. Compared to the structure, since there is no difficulty in manufacturing a mold for resin-molding the optical connector body, a desired internal reflection surface can be formed.
When a plurality of internal reflection surfaces are provided with high accuracy on one wide mold surface, it is not easy to process all the internal reflection surfaces on one wide mold surface with high accuracy. By adopting a structure that forms the bottomed holes, the internal reflection surface can be formed with high accuracy only by maintaining the precision of the mold (core) for forming the individual bottomed holes and the precision of the arrangement pitch.
When forming an internal reflection surface that collects light as an internal reflection surface (a minute curved surface that is a spherical surface or a rotating parabolic surface), the minute curved surface is accurately applied to the tip of a mold (core) for forming a bottomed hole. Forming is considerably easier and less expensive to manufacture than a conventional product that forms a plurality of minute curved surfaces with high accuracy on a wide surface of a large-size mold.
In addition, even if there is a design change in the arrangement, number, or reflection direction of the internal reflection surfaces, it can be handled by changing the number and direction of the molds (cores). This is advantageous compared to processing a plurality of internal reflection surfaces.

It is a perspective view of the optical connector of one Example of this invention. It is the perspective view which looked at the said optical connector from the attachment surface side. It is a notch perspective view of the said optical connector. It is a top view of the said optical connector. It is a figure explaining the curved surface shape of the internal reflection surface by the bottom face of the bottomed hole formed in the optical connector. It is AA sectional drawing of FIG. It is sectional drawing shown in the state which attached the optical fiber to the said optical connector, and was mounted in the circuit board. It is a principal part enlarged view of FIG. It is sectional drawing which shows the other Example of an optical connector. It is sectional drawing of the conventional optical connector.

  Hereinafter, an optical connector embodying the present invention will be described with reference to the drawings.

1 is a perspective view of an optical connector 1 according to an embodiment of the present invention, FIG. 2 is a perspective view as viewed from the mounting surface side, FIG. 3 is a cutaway perspective view, FIG. 4 is a plan view, and FIG. AA sectional view, FIG. 7 is a sectional view showing an optical fiber attached and mounted on a circuit board.
As shown in FIG. 7, the optical connector 1 of this embodiment is installed in an optical module 3 on which an optical element 2 is mounted, and an optical fiber 4 introduced in parallel with the surface 3a of the optical module and the optical element 2 An optical connector that inputs and outputs optical signals by changing the optical path by internal reflection.
In other words, the optical connector connects the first optical path on the optical fiber side and the second optical path on the optical element side that intersects the first optical path.
Hereinafter, unless otherwise specified, in FIG. 7, the left side of the page is the front, the right side of the page is the rear, the upper side of the page is the upper side, and the lower side of the page is the lower side.

  The main body (optical connector main body) 6 of the optical connector 1 is a resin molded product made of a light-transmitting resin that efficiently transmits light having a signal wavelength to be used (for example, 850 nm, 1310 nm, and 1550 nm). As the light transmissive resin, PC (polycarbonate), PEI (polyetherimide), PPA (polyphthalamide), or the like can be used.

The optical connector main body 6 is formed with a hollow portion 9 in which an optical fiber introduction opening 7 that opens to the rear of the main body communicates with an adhesive filling window 8 that opens upward.
An optical fiber guide groove 10 by, for example, a V-groove is provided in a lower portion of the adhesive filling window 8 in the hollow portion 9, and the front end of each optical fiber guide groove 10 (the left end in FIGS. 3 to 7 and the like). An optical fiber insertion hole 11 extending forward is formed.
The front end side of the optical fiber 4 is a bare optical fiber from which the coating has been removed, and this bare optical fiber is inserted into the optical fiber insertion hole.

The front of the optical fiber insertion hole 11 (the front of the front end of the optical fiber insertion hole 11) is a recess 12 that opens to the upper surface of the main body, and the front wall surface of the recess 12 is an optical fiber abutting surface 12a. . The optical fiber 4 inserted into the optical fiber insertion hole 11 passes through the recess 12 and is abutted against the front wall surface 12 a of the recess 12.
An optical fiber guide groove 13 such as a groove having a U-shaped cross section is formed on the bottom of the recess 12 as necessary.

As shown in FIG. 4, an internal reflection surface 15a is formed in front of the optical connector main body 6 in the vicinity of the optical fiber contact surface 12a.
One internal reflection surface 15a is formed for one optical fiber.
That is, one internal reflection surface 15a is formed for one optical path.
The internal reflection surface 15a is a bottom surface of a bottomed hole 15 that is deeply drilled from the inclined outer surface 16 of the optical connector body 6 toward the front of the optical fiber butting surface 12a.

The optical connector 1 to which the tape-shaped multi-fiber optical fiber 4 is attached will be described with reference to FIG.
A tape coating portion of the optical fiber (optical fiber tape) 4 is denoted by 4c, an optical fiber strand portion from which the tape coating has been removed is denoted by 4b, and a bare fiber portion is denoted by 4a.
The optical fiber tape 4 is inserted from the optical fiber introduction opening 7.
Although not particularly shown, a strain relief protective member is provided between the covering portion of the tape and the optical fiber introduction opening 7.
The protective member is, for example, a protective boot made of an elastic body or a flexible adhesive filled in a gap.
A plurality of optical fibers (bare fibers) 4a from which the resin coating at the tip of the optical fiber tape 4 has been completely removed are inserted into a plurality of optical fiber insertion holes 11 in front of the optical fiber guide groove 10 as a guide.
The inner diameter of the optical fiber insertion hole 11 is about several μm larger than the outer diameter of the bare optical fiber.
When the optical fiber tape 4 is further pushed in, the optical fiber abutment surface 12a which is the front wall surface of the recess 12 in front of the optical fiber tape 4 is abutted, and the tip position of the optical fiber tape 4 is determined.
Next, the optical fiber is fixed by filling the adhesive 18 from the adhesive filling window 8. At the same time, the recess 12 is filled with the adhesive 18 '. Bubbles generated when the adhesive is filled are discharged from the recess 12 and the adhesive filling window 8.
The filled adhesives 18 and 18 ′ contract when cured, but both the recesses 12 and 18 communicate with the outside air, so that the contraction strain (internal stress) is released to the outside, which affects the position of the optical fiber. Will not affect.
When the recess 12 is not provided, the back end of the optical fiber insertion hole 11 serves as an optical fiber abutting surface.

  As shown in FIG. 7, the optical connector 1 to which the optical fiber 4 is attached is positioned and mounted on the optical module 3 on which the optical element 2 such as a VCSEL or PD is mounted so as to be optically coupled to the optical element 2 correctly. It is done. In this figure, the optical module 3 is mounted on the circuit board 19, but the optical element is directly mounted on the circuit board 19 without using the optical module 3, and the optical connector 1 is attached to the circuit board 19. It is also possible to adopt a configuration in which the surface (lower surface) is placed.

The light emitted from the tip of the optical fiber 4a is transmitted through the transparent resin in the optical connector body 6 from the optical fiber abutting surface 12a which is the wall surface of the recess 12, and is transmitted through the bottom surface of the bottomed hole 15, that is, the internal reflection surface 15a. Internally reflected to change the optical path at a right angle downward.
The light whose path has been changed passes through the transparent resin and enters the optical element 2 on the optical module 3.
The light emitted from the optical element 2 enters the core of the optical fiber 4a via the reverse optical path.

Next, the shape of the internal reflection surface 15a will be described.
A bottom surface (internal reflection surface) 15a of the bottomed hole 15 is a flat surface or a curved surface convex toward the hole opening side.
The area of the internal reflection surface as viewed from the light incident / exit direction is approximately enough to cover the spot diameter of the light.
That is, when viewed from the inside of the optical connector, the internal reflection surface 15a is a plane mirror or a concave mirror that performs a light collecting action.
The concave surface is a concave surface made of an aspherical surface such as a spherical surface or a parabolic surface (parabolic surface), for example.
When the internal reflection surface is a plane, the bottom surface 15 a of the bottomed hole 15 can be perpendicular to the central axis 15 c of the bottomed hole 15.
For example, when the bottomed hole 15 is formed perpendicular to the extending direction of the inclined outer surface 16, the bottom surface 15 a of the bottomed hole 15 is parallel to the inclined outer surface 16.
However, the central axis 15 c of the bottomed hole 15 is not limited to a direction perpendicular to the inclined outer surface 16.

In FIG. 8, the bottom surface 15a is a concave surface symmetrical with respect to the central axis 15c.
And if it is a concave surface, the light emitted from the optical fiber 4a is condensed so as to be correctly focused on the optical element 2, and the light emitted from the optical element 2 is incident on the core of the optical fiber 4a without being diffused. Let That is, the optical coupling efficiency can be improved.
In this way, optical signals are input / output between the optical element 2 on the circuit board 3 and the optical fiber 4a on the optical connector 1 side.

The optical connector body 6 can be formed by, for example, injection molding.
When the optical connector body 6 is molded, the cavity formed in the mold is filled with a light transmitting resin and molded.
In this case, a metal core pin having a shape corresponding to the shape of the bottomed hole 15 is disposed in the cavity as a mold part for forming the bottomed hole 15.
Hereinafter, the case where the bottom surface 15a of the bottomed hole 15 is not a flat surface but a curved surface convex toward the hole opening side will be described.
A metal core pin (core pin having a concave surface at the tip) having a concave surface on the tip surface of the round bar is disposed at a predetermined position.
Here, compared with the conventional case, conventionally, a plurality of minute curved surfaces are integrally processed on the outer surface of the mold.
For this reason, it is necessary to process a plurality of concave portions that form a plurality of minute curved surfaces on one surface of the mold piece that forms the outer surface, but it is not easy to manufacture such a high-precision mold piece. For example, if the accuracy of some of the plurality of recesses is poor or the arrangement pitch of the recesses collapses, the mold piece becomes a defective product, making it difficult to manufacture the mold, and the cost is very high. It tends to be expensive.
However, in the case of the optical connector body 6, the core that forms a minute curved surface that requires high accuracy is a set of rod-shaped core pins whose thin cross section is circular.
Forming a concave surface with high precision by grinding the tip of a metal core pin, chipping, or other means compared to forming multiple concave surfaces with high precision on a large surface of a large die. It's pretty easy.
If the accuracy of the minute curved surface at the tip of the core pin is poor, it is only necessary to replace that one core pin with a non-defective product. Compared to conventional products that are impossible, it is easy to prepare a mold and the cost is also reduced.

In addition, when it is desired to change the arrangement pitch of optical fibers, the number of arrangement stages, and the reflection angle, in the case of the conventional product, a mold piece having a plurality of minute curved surfaces corresponding to the pitch must be manufactured completely, which is complicated. And expensive.
Here, the change in the arrangement pitch is a change in the interval between the internal reflection surfaces, the number of the internal reflection surfaces, and the like, and the change in the number of steps in the array means that the internal reflection surfaces are arranged in two rows or more. The case where it arranges to.
On the other hand, in the case of a mold for resin molding the optical connector body 6 of the present invention, it is only necessary to change the interval of the same core pins or change the arrangement of the core pins as appropriate. Compared to manufacturing, it is extremely simple and does not cost much.
That is, for example, when changing the angle of the minute curved surface (changing the optical path conversion direction) or changing the size or curvature of the minute curved surface, if it is a conventional product, it is a new Since a mold piece having a minute curved surface or flat surface of the specification has to be manufactured completely, the mold cost becomes high.
The same applies to not only a minute curved surface but also a flat surface.
On the other hand, according to the present invention, since only the core pin needs to be changed, it is very easy to cope with the specification change of the internal reflection surface, and the cost can be reduced.
As described above, since there is no difficulty in manufacturing a mold in the conventional structure of forming a plurality of minute reflecting surfaces on a wide surface of a large-sized mold, a desired internal reflecting surface can be freely formed. Is possible.

Next, the curved surface shape of the internal reflection surface 15a by the bottom surface 15a of the bottomed hole 15 will be described in more detail.
FIG. 5 is a cross-sectional view of the bottomed hole 15. In this figure, the central axis of the concave reflecting surface 15a by the bottom surface 15a of the bottomed hole 15 is the central axis 15c of the bottomed hole 15, as in FIG. The sectional contour of the concave reflecting surface 15a is symmetrical with respect to the central axis 15c.
Such a symmetrical concave reflecting surface 15a can be easily manufactured with high accuracy.
For example, when the core pin is disposed downward in the direction of 45 degrees from the outer surface of the optical connector as in the first embodiment, the optical axis of the optical fiber and the optical axis of the light emitting / receiving element can be crossed at 90 degrees.
In addition, although not shown in particular, it is also possible to process the shape such that the curvature of the concave reflecting surface 15a changes.

When attaching the optical connector 1 to the optical module 3, it is necessary to accurately position the optical connector 1 with respect to the optical element 2 on the optical module 3.
As this positioning means, for example, a fitting convex portion can be formed on the bottom surface of the optical connector body, and a fitting concave portion for receiving the fitting convex portion can be provided on the optical module side for positioning.
Alternatively, a fitting recess can be formed on the bottom surface of the optical connector body, and a fitting protrusion can be provided on the optical module side to fit the fitting recess.
In addition, the positioning means between the optical connector and the optical module can be appropriately changed in design, and various shapes can be adopted.

  Although the flat surface is easier to manufacture than the concave surface, the advantages of the conventional product are the same.

FIG. 9 shows another embodiment of the present invention.
In this embodiment, the bottom surface 25a of the bottomed hole 25 is a flat surface, and the internal reflection surface 25a functions as a simple plane mirror.
A concave portion 26b may be formed in a portion of the optical connector main body 26 facing the optical element 2, and the lens portion 28 having a condensing action may be formed by making the upper surface of the concave portion 26b into a spherical convex shape.
As a result, the light emitted from the optical fiber is condensed so as to be correctly focused on the optical element 2, and the light emitted from the optical element 2 is incident on the core of the optical fiber without being diffused.
The lens portion 28 can be formed not only when the planar internal reflection surface 25a is formed, but also when an internal reflection surface that collects light is formed.

In each of the above embodiments, the light incident / exit surface (the lower surface of the optical connector main body (including the case where the lens portion 28 is formed)) is a non-reflective surface, so that light in light transmission from the optical element to the optical fiber can be obtained. It is effective for reducing the loss.
As a means for providing a non-reflective surface, a method of applying a non-reflective (AR) coating by depositing a dielectric film on the light incident / exit surface by sputtering can be employed.
Further, a non-reflective function can be provided by a fine structure in which fine irregularities are arranged on the light incident / exit surface with a period smaller than the optical signal wavelength to be used.
In addition, as a means for condensing the internal reflection surface, a rotating parabolic surface is formed in the bottomed hole in the embodiment, but a ring-shaped unevenness (an unevenness in which the unevenness is repeated in the radial direction) is formed on the bottom surface of the bottomed hole. It is also possible to form an internal reflection surface having a light collecting action.
In the above description, the optical connector has been described. However, the present invention can be applied to a so-called optical fiber array.

  In the present invention, it is only necessary that at least a portion of the resin that transmits light between the optical fiber insertion hole, the internal reflection surface, and the optical element is transparent. Since the other part is a part through which light does not pass, it can be made of colored resin or other materials.

DESCRIPTION OF SYMBOLS 1, 21 Optical connector 2 Optical element 3, 23 Circuit board 3a, 23a Substrate surface 4 Optical fiber 6, 26 Optical connector main body 26a Installation surface 26b Recess 7 Optical fiber introduction opening 8 Adhesive filling window 9 Hollow part 10 Light Fiber guide groove 11 Optical fiber insertion hole 12 Recess 12a Optical fiber abutting surface 13 Optical fiber guide grooves 15, 25 Bottomed holes 15a, 25a Internal reflection surface (bottom of bottomed hole)
16 Inclined outer surface 18, 18 'Adhesive 28 Lens part

Claims (6)

The plurality of first optical paths on the optical fiber side inserted in optical fiber insertion holes formed in parallel with the upper surface of the circuit board on which the optical elements are mounted, and the optical elements intersecting the first optical paths, respectively, due to internal reflection In an optical connector for coupling a plurality of second optical paths on the side,
The optical connector body is a resin molded product,
The rear of the optical fiber insertion hole is an optical fiber introduction opening that opens to the rear of the optical connector body, and a hollow portion that is filled with an adhesive that opens to the top of the optical connector body,
In front of the optical fiber insertion hole, a recess is formed that opens above the optical connector body and can be filled with an adhesive, and the front of the insertion hole in the recess is an abutting surface of the optical fiber. ,
The optical connector body has an internal reflection surface in the optical connector body in front of the optical fiber insertion hole,
The resin between the optical fiber insertion hole and the internal reflection surface, and the internal reflection surface and the optical element is transparent,
The internal reflection surface is opened from the outer surface to the optical connector main body for each optical fiber in a direction that intersects each optical fiber extension direction at an angle of less than 90 ° and to a position in front of the optical fiber abutting surface. The bottom surface of the bottomed hole is symmetrical with respect to the axis of the bottomed hole,
An optical connector, wherein the optical fiber and the optical element are optically coupled by the internal reflection surface.   2. The optical connector according to claim 1, wherein the bottomed hole is formed in the optical connector main body from an inclined outer surface inclined at an angle of less than 90 degrees with respect to a surface orthogonal to the optical fiber extending direction. .   3. The optical connector according to claim 1, wherein the bottom surface of the bottomed hole is a flat surface or a curved surface convex toward the hole opening side.   4. The optical connector according to claim 3, wherein when the bottom surface of the bottomed hole is a flat surface, a lens portion for condensing light is formed on the light incident / exit surface of the connector main body with respect to the optical element on the circuit board. .   4. The optical connector according to claim 3, wherein when the bottom surface of the bottomed hole is a curved surface convex toward the hole opening side, the input / output surface of the connector body with respect to the optical element on the circuit board is flat.   2. The optical connector according to claim 1, wherein an optical fiber guide groove for guiding the optical fiber is formed at the bottom of the recess.

Images