Optical coupler, photoelectric conversion circuit module, and optical transceiver

Abstract

To provide an optical coupler, a photoelectric conversion circuit module, and an optical transceiver that are capable of suppressing incidence of light emitted from one optical fiber on the other optical fiber while facilitating alignment.SOLUTION: An optical coupler is integrally molded with a material including a glass and fillers mixed in the glass, the optical coupler comprising: an optical fiber fixing part fixing each of a plurality of optical fibers emitting light in a first direction; an incidence surface on which the light emitted from any one of the plurality of optical fibers is incident; a reflection surface which changes a travelling direction of the light made incident from the incidence surface, from the first direction into a second direction orthogonal to the first direction; and an emission surface emitting to the second direction the light the travelling direction of which is changed by the reflection surface. As viewed in a third direction orthogonal to the first direction and the second direction, an angle formed between the incidence surface and the first direction is an acute angle or an obtuse angle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical coupler, an optoelectronic conversion circuit module, and an optical transceiver. [Background technology]

[0002] As an example of an invention relating to a conventional optical coupler, an optical connector portion described in Patent Document 1 is known. The optical connector portion described in Patent Document 1 includes a glass holding member and an optical path conversion member. The holding member and the optical path conversion member are separate members. The holding member holds an end of an optical fiber. The optical path conversion member has a lens portion that reflects an optical signal while focusing it. The end face of the optical fiber and the end face of the holding member are obliquely polished. The optical path conversion member is fixed to the obliquely polished end face of the optical fiber and the end face of the holding member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-79862 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the optical connector portion described in Patent Document 1, alignment is difficult because there is a misalignment between the angle of the oblique polishing of the end face of the optical fiber and the angle of the oblique polishing of the end face of the holding member.

[0005] Incidentally, in the field of optical couplers such as the optical connector section described in Patent Document 1, glass may contain a filler to improve the strength of the glass. In this case, the filler may be exposed on the surface of the glass. When multiple optical fibers are arranged side by side, light emitted from one optical fiber may be scattered by the filler exposed on the surface of the glass and enter another optical fiber, adversely affecting the propagation mode.

[0006] Therefore, an object of the present invention is to provide an optical coupler, an optoelectronic conversion circuit module, and an optical transceiver that can easily align the optical fibers while preventing light emitted from one optical fiber from entering another optical fiber. [Means for solving the problem]

[0007] An optical coupler according to one aspect of the present invention comprises: An optical coupler integrally formed from a material including glass and a filler mixed in the glass, an optical fiber fixing portion that fixes each of a plurality of optical fibers that emit light in a first direction; an incident surface on which the light emitted from any one of the plurality of optical fibers is incident; a reflecting surface that changes a traveling direction of the light incident on the incident surface from the first direction to a second direction perpendicular to the first direction; an exit surface that outputs the light, the direction of which has been changed by the reflecting surface, in the second direction; Equipped with the plurality of optical fibers are arranged in a third direction perpendicular to the first direction and the second direction, a plurality of condensing lens portions are provided on the reflecting surface to condense the light traveling in the first direction and reflect the light toward the second direction, The plurality of condenser lens portions are aligned in the third direction, When viewed in the third direction, the angle formed between the incident surface and the first direction is an acute angle or an obtuse angle. Effect of the Invention

[0008] The optical coupler, photoelectric conversion circuit module, and optical transceiver according to the present invention can facilitate alignment and prevent light emitted from one optical fiber from entering another optical fiber. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an optical coupler 1. As shown in FIG. [Diagram 2]FIG. 2 is a cross-sectional view of the optical coupler 1 and the optical fiber 5. As shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view of the reflecting portion 3 and the optical fiber 5 taken along the line AA. [Figure 4] FIG. 4 is a plan view of the optical coupler 1 as viewed in the opposite direction to the second direction DIR2. [Diagram 5] FIG. 5 is a cross-sectional view of an optical coupler 50 and an optical fiber 5 according to a comparative example. [Figure 6] FIG. 6 is a plan view of the reflector 3 and the optical fiber 5 according to the comparative example, viewed in the second direction DIR2. [Figure 7] FIG. 7 is a cross-sectional view of the optical coupler 1 and the optical fiber 5. As shown in FIG. [Figure 8] FIG. 8 is an enlarged schematic cross-sectional view of the incident surface S11 and the adjacent optical fibers 5 in FIG. [Figure 9] FIG. 9 is a cross-sectional view of the incident surface S11 and the optical fiber 5. As shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view of the optical coupler 1 a and the optical fiber 5 . [Figure 11] FIG. 11 is a perspective view of the photoelectric conversion circuit module 10 and the optical fiber 5. As shown in FIG. [Figure 12] FIG. 12 is a BB cross-sectional view of the photoelectric conversion circuit module 10 and the optical fiber 5. As shown in FIG. [Figure 13] FIG. 13 is a perspective view of the photoelectric conversion circuit module 10a and the optical fiber 5. As shown in FIG. [Figure 14] FIG. 14 is a perspective view of the optical transceiver 100 and the optical fiber 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] [Structure of optical coupler 1] Hereinafter, an optical coupler 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the optical coupler 1. In FIG. 1, only a representative filler P1 among a plurality of fillers P1 is given a reference symbol. FIG. 2 is a cross-sectional view of the optical coupler 1 and an optical fiber 5. In FIG. 2, the second side wall portion 22 and the third side wall portion 23 are omitted. FIG. 3 is a cross-sectional view of the reflector 3 and the optical fiber 5 taken along line AA. FIG. 4 is a plan view of the optical coupler 1 viewed in the opposite direction to the second direction DIR2.

[0011] In this specification, the directions are defined as follows. As shown in FIG. 1, the direction in which the optical fiber fixing portion 4 and the reflecting portion 3 are arranged in this order is defined as a first direction DIR1. The direction in which the reflecting portion 3 and the bottom portion 24 are arranged in this order is defined as a second direction DIR2. The direction in which the second side wall portion 22 and the third side wall portion 23 are arranged in this order is defined as a third direction DIR3. The first direction DIR1, the second direction DIR2, and the third direction DIR3 are perpendicular to each other. However, the first direction DIR1, the second direction DIR2, and the third direction DIR3 in this specification are directions defined for the convenience of explanation, and do not have to match the first direction DIR1, the second direction DIR2, and the third direction DIR3 when the optical coupler 1 is in use.

[0012] The optical coupler 1 is a device for changing the traveling direction of light emitted from an optical fiber and outputting it to a photoelectric conversion circuit or the like, or for changing the traveling direction of light emitted from a photoelectric conversion circuit or the like and outputting it to an optical fiber. In this embodiment, a case will be described in which the optical coupler 1 changes the traveling direction of the light L emitted from the optical fiber 5 from a first direction DIR1 to a second direction DIR2. As shown in FIG. 2, the optical coupler 1 has an incident surface S11 on which the light L emitted from the optical fiber 5 is incident, and an output surface S12 from which the light L is output in the second direction DIR2. The structure of the optical coupler 1 will be described in detail below.

[0013] As shown in Fig. 1, the optical coupler 1 includes a holding section 2, a reflecting section 3, and an optical fiber fixing section 4. The optical coupler 1 is integrally molded from glass containing a filler. The optical coupler 1 is a single member. Here, a single member means a member having a structure that cannot be separated without being damaged. Therefore, for example, a member in which two resin pieces are fixed with a screw is not a single member.

[0014] The optical coupler 1 is integrally molded from a material including glass M1 and a plurality of fillers P1 mixed in the glass M1. Glass is an amorphous material that exhibits a glass transition phenomenon. Examples of glass include simple oxide glasses such as SiO2, B2O3, P2O5, GeO2, and AS3O3, silicate glasses such as Li2O-SiO2, Na2O-SiO2, and K2O-SiO2, aluminosilicate glasses such as Na2O-Al2O3-SiO2 and CaO-Al2O3-SiO2, borate glasses such as Li2O-B2O3 and Na2O-B2O3, aluminoborate glasses such as CaO-Al2O3-B2O3, and borosilicate glasses such as Na2O-Al2O3-B2O3-SiO2.

[0015] The plurality of fillers P1 are metal oxide particles such as crystalline silica, amorphous silica, alumina, magnesium oxide, and titanium oxide. Each of the plurality of fillers P1 has a non-spherical shape. The plurality of fillers P1 are dispersed throughout the glass M1. Each of the plurality of fillers P1 may have a spherical shape. The plurality of fillers P1 may be uniformly dispersed throughout the glass M1, or may be non-uniformly dispersed throughout the glass M1.

[0016] The longest length of each of the multiple fillers P1 is r. When each of the multiple fillers P1 has a spherical shape, the longest length r of each of the multiple fillers P1 is the diameter of the sphere. When each of the multiple fillers P1 has an ellipsoidal shape, the longest length r of each of the multiple fillers P1 is the length in the major axis direction of the ellipsoidal sphere. In this way, the longest length r of each of the multiple fillers P1 is the longitudinal length of the longest part of each of the multiple fillers P1. The wavelength of the light L is λ. In this case, the following mathematical formula 1 is satisfied.

[0017]

number

[0018] The holding portion 2 holds each of the reflecting portion 3 and the optical fiber fixing portion 4. The holding portion 2 is connected to each of the reflecting portion 3 and the optical fiber fixing portion 4. The holding portion 2 includes a first side wall portion 21, a second side wall portion 22, a third side wall portion 23, and a bottom portion 24. Note that the holding portion 2 does not necessarily include each of the first side wall portion 21, the second side wall portion 22, and the third side wall portion 23.

[0019] The first side wall portion 21 is connected to each of the second side wall portion 22, the third side wall portion 23, and the bottom portion 24. More specifically, the first side wall portion 21 has a shape extending in the third direction DIR3. In this embodiment, the first side wall portion 21 has a plate shape. An end face of the first side wall portion 21 in the third direction DIR3 is connected to the third side wall portion 23. An end face of the first side wall portion 21 in the opposite direction to the third direction DIR3 is connected to the second side wall portion 22. An end face of the first side wall portion 21 in the second direction DIR2 is connected to the bottom portion 24. Note that the first side wall portion 21 does not have to have a plate shape.

[0020] The second side wall portion 22 is connected to each of the first side wall portion 21, the bottom portion 24, the reflecting portion 3, and the optical fiber fixing portion 4. More specifically, the second side wall portion 22 has a shape extending in the first direction DIR1. In this embodiment, the second side wall portion 22 has a plate shape. A portion of the end face of the second side wall portion 22 in the third direction DIR3 is connected to each of the end face of the first side wall portion 21 in the opposite direction to the third direction DIR3, the reflecting portion 3, and the optical fiber fixing portion 4. The end face of the second side wall portion 22 in the second direction DIR2 is connected to the bottom portion 24. Note that the second side wall portion 22 does not have to have a plate shape.

[0021] The third side wall 23 is connected to each of the first side wall 21, the bottom 24, the reflector 3, and the optical fiber fixing part 4. More specifically, the third side wall 23 has a shape extending in the first direction DIR1. In this embodiment, the third side wall 23 has a plate shape. A portion of the end face of the third side wall 23 in the direction opposite to the third direction DIR3 is connected to each of the end face of the first side wall 21 in the third direction DIR3, the reflector 3, and the optical fiber fixing part 4. The end face of the third side wall 23 in the second direction DIR2 is connected to the bottom 24. Note that the third side wall 23 does not have to have a plate shape.

[0022] The bottom 24 is connected to each of the first side wall 21, the second side wall 22, the third side wall 23, the reflector 3, and the optical fiber fixing portion 4. More specifically, the bottom 24 has a plate shape. In this embodiment, the bottom 24 has a rectangular shape when viewed in the second direction DIR2. A portion of the end face of the bottom 24 in the opposite direction to the second direction DIR2 is connected to each of the end face of the first side wall 21 in the second direction DIR2, the end face of the second side wall 22 in the second direction DIR2, the end face of the third side wall 23 in the second direction DIR2, the reflector 3, and the optical fiber fixing portion 4. Note that the bottom 24 does not have to have a rectangular shape when viewed in the second direction DIR2.

[0023] The optical fiber fixing part 4 fixes each of the five optical fibers 5. The optical fiber fixing part 4 is connected to each of the second side wall part 22, the third side wall part 23 and the bottom part 24. More specifically, the optical fiber fixing part 4 has a plate shape extending in the third direction DIR3. An end face of the optical fiber fixing part 4 in the third direction DIR3 is connected to the third side wall part 23. An end face of the optical fiber fixing part 4 in the opposite direction to the third direction DIR3 is connected to the second side wall part 22. An end face of the optical fiber fixing part 4 in the second direction DIR2 is connected to the bottom part 24.

[0024] Five grooves G having a V-shape are provided on the end face of the optical fiber fixing part 4 in the direction opposite to the second direction DIR2 when viewed in the first direction DIR1. Each of the five grooves G has a shape extending in the first direction DIR1. The five grooves G are arranged in the third direction DIR3. As shown in FIG. 2, each of the five grooves G is fixed to each of the five optical fibers 5. As a result, the five optical fibers 5 are arranged in the third direction DIR3. Note that the grooves G may not be provided on the end face of the optical fiber fixing part 4 in the direction opposite to the second direction DIR2. Also, each of the five grooves G may have a U-shape when viewed in the first direction DIR1. Also, the number of optical fibers 5 is not limited to five, and may be any number more than one.

[0025] Each of the five optical fibers 5 has a shape extending in the first direction DIR1. Each of the five optical fibers 5 has an end face S5 from which light L is emitted. The normal direction of the end face S5 of each of the five optical fibers 5 is the first direction DIR1. Each of the five optical fibers 5 emits light L in the first direction DIR1. The end face S5 of each of the five optical fibers 5 faces the reflecting unit 3 with a gap therebetween. The light L emitted from any of the five optical fibers 5 travels in the first direction DIR1 and enters the reflecting unit 3. In this embodiment, the distance p between the centers of the end faces S5 of two adjacent optical fibers 5 along the third direction DIR3 is the distance between the bottoms of two adjacent grooves G along the third direction DIR3.

[0026] As shown in Fig. 1, the reflecting portion 3 is connected to each of the second side wall portion 22, the third side wall portion 23, and the bottom portion 24. As shown in Fig. 2, the reflecting portion 3 changes the traveling direction of the light L incident from the incident surface S11 from a first direction DIR1 to a second direction DIR2. The reflecting portion 3 includes a prism portion 31 and five condenser lens portions 32. Note that the number of condenser lens portions 32 is not limited to five, and may be any number more than one.

[0027] The prism portion 31 is connected to each of the second side wall portion 22, the third side wall portion 23, and the bottom portion 24. More specifically, in this embodiment, the prism portion 31 has a triangular prism shape extending in the third direction DIR3. The prism portion 31 has a prism portion entrance surface S2, a prism portion reflection surface S3, and a prism portion exit surface S4. Note that the prism portion 31 does not have to have a triangular prism shape.

[0028] The prism portion incident surface S2 is an end surface of the prism portion 31 in the opposite direction to the first direction DIR1. Light L emitted from any of the five optical fibers 5 enters the optical coupler 1 from the prism portion incident surface S2. Therefore, the prism portion incident surface S2 is the incident surface S11 of the optical coupler 1. The light L entering the optical coupler 1 from the prism portion incident surface S2 passes through the inside of the prism portion 31.

[0029] In this embodiment, the angle θ between the prism portion entrance surface S2 and the first direction DIR1 is an acute angle when viewed in the third direction DIR3. More specifically, in this embodiment, the angle θ between the prism portion entrance surface S2 and the first direction DIR1 is greater than 0 degrees and less than 90 degrees in a counterclockwise direction when viewed in the third direction DIR3. In this embodiment, the angle θ is 86.5 degrees. Note that when the angle θ is an acute angle, it is preferable that the angle θ be greater than 0 degrees and less than or equal to 86.5 degrees in a counterclockwise direction.

[0030] 3, the distance along the first direction DIR1 between the center of the end face S5 of each of the multiple optical fibers 5 and the prism portion entrance surface S2 is defined as d. The distance d along the first direction DIR1 between the center of the end face S5 of each of the multiple optical fibers 5 and the prism portion entrance surface S2 is greater than 0 and less than the distance p along the third direction DIR3 between the centers of the end faces S5 of two adjacent optical fibers 5.

[0031] As shown in Fig. 2, the prism portion reflecting surface S3 forms an angle of 135 degrees clockwise with respect to the first direction DIR1 when viewed in the third direction DIR3. The end of the prism portion reflecting surface S3 in the direction opposite to the second direction DIR2 is located in the opposite direction of the first direction DIR1 from the end of the prism portion reflecting surface S3 in the second direction DIR2. The prism portion reflecting surface S3 reflects the light L that has passed through the inside of the prism portion 31. As a result, the prism portion reflecting surface S3 changes the traveling direction of the light L from the first direction DIR1 to the second direction DIR2. The prism portion reflecting surface S3 corresponds to the "reflecting surface" of the present invention.

[0032] The five condenser lens sections 32 are provided on the prism section reflecting surface S3. The five condenser lens sections 32 are arranged in the third direction DIR3. The surface of the condenser lens section 32 is aspheric. In this embodiment, the surface of the condenser lens section 32 is ellipsoidal. The condenser lens section 32 condenses the light L passing through the inside of the prism section 31 and traveling in the first direction DIR1, while reflecting the light L toward the second direction DIR2. As a result, the condenser lens section 32 changes the traveling direction of the light L from a direction including a component of the first direction DIR1 to the second direction DIR2. The surface of the condenser lens section 32 does not have to be ellipsoidal.

[0033] The prism portion exit surface S4 is an end surface of the prism portion 31 in the second direction DIR2. The prism portion exit surface S4 is connected to the bottom portion 24. The prism portion exit surface S4 emits light L that is reflected by the prism portion reflecting surface S3 or the condenser lens portion 32 and passes through the inside of the prism portion 31. The light L emitted from the prism portion exit surface S4 enters the bottom portion 24 from an end surface of the bottom portion 24 in the opposite direction to the second direction DIR2.

[0034] The light L incident on the bottom 24 from an end face of the bottom 24 in the opposite direction to the second direction DIR2 passes through the inside of the bottom 24 and is emitted to the outside of the optical coupler 1 from an end face S1 of the bottom 24 in the second direction DIR2. Therefore, the end face S1 of the bottom 24 in the second direction DIR2 includes the emission surface S12 of the optical coupler 1.

[0035] Here, as shown in FIG. 4, in the end face S1 of the bottom 24 in the second direction DIR2, a region that overlaps with the reflecting portion 3 when viewed in the second direction DIR2 is defined as a region A1. In addition, in the end face S1 of the bottom 24 in the second direction DIR2, a region that does not overlap with the reflecting portion 3 when viewed in the second direction DIR2 is defined as a region A2. The end face S1 of the bottom 24 in the second direction DIR2 includes both the region A1 and the region A2. The light L is emitted from the region A1 of the bottom 24 to the outside of the optical coupler 1. Therefore, the region A1 is the emission surface S12. The region A2 is a mounting surface S22 for mounting the optical coupler 1 on a substrate when the optical coupler 1 is incorporated in a photoelectric conversion circuit module 10 described later or the like. The end face S1 of the bottom 24 in the second direction DIR2 includes the emission surface S12 and the mounting surface S22. That is, the mounting surface S22 is in the same plane as the emission surface S12.

[0036] [effect] The optical coupler 1 can facilitate alignment. More specifically, the optical coupler 1 is integrally molded from a material including glass M1 and a plurality of fillers P1 mixed in the glass M1, and is not obliquely polished. The optical fiber 5 is also not obliquely polished. The optical fiber 5 is fixed to the optical fiber fixing portion 4. Therefore, the optical coupler 1 can facilitate alignment.

[0037] Moreover, the optical coupler 1 can prevent light emitted from one optical fiber from entering another optical fiber. As a comparative example, an optical coupler 50 in which the angle θ between the prism portion entrance surface S2 and the first direction DIR1 is a right angle when viewed in the third direction DIR3 will be described with reference to the drawings. Fig. 5 is a cross-sectional view of the optical coupler 50 and the optical fiber 5 according to the comparative example. Fig. 6 is a plan view of the reflector 3 and the optical fiber 5 according to the comparative example when viewed in the second direction DIR2. Fig. 7 is a cross-sectional view of the optical coupler 1 and the optical fiber 5.

[0038] The optical fiber 5 that emits the light L is defined as the optical fiber 51. The optical fiber 5 next to the optical fiber 51 is defined as the optical fiber 52. The optical fiber 5 other than the optical fiber 51 and the optical fiber 52 is defined as the optical fiber 53. As shown in FIG. 6, a part of the light L emitted from the optical fiber 51 is reflected by the prism part incident surface S2. At this time, since the filler P1 is present near the prism part incident surface S2, a part of the light L emitted from the optical fiber 51 is easily reflected in a direction in which the optical fiber 51 is not arranged. In this case, in the optical coupler 50 according to the comparative example, the angle θ between the prism part incident surface S2 and the first direction DIR1 is a right angle when viewed in the third direction DIR3, so that the reflected light RL is less likely to deviate from the optical fiber 52 and the optical fiber 53 in the second direction DIR2 or in the opposite direction to the second direction DIR2. Therefore, the reflected light RL is easily incident on the optical fiber 52 and the optical fiber 53.

[0039] Therefore, according to the optical coupler 1, the angle θ between the prism portion incident surface S2 and the first direction DIR1 is an acute angle when viewed in the third direction DIR3. Therefore, as shown in FIG. 7, the reflected light RL is more likely to be shifted in the second direction DIR2 or in the opposite direction to the second direction DIR2 than the optical fiber 52 and the optical fiber 53. As a result, even if a part of the light L emitted from the optical fiber 51 is reflected in a direction in which the optical fiber 51 is not arranged, the reflected light RL is less likely to be incident on the optical fiber 52 and the optical fiber 53. Therefore, according to the optical coupler 1, it is possible to prevent the light emitted from one optical fiber from being incident on another optical fiber. As a result, according to the optical coupler 1, it is possible to prevent the light emitted from one optical fiber from being incident on another optical fiber while facilitating alignment.

[0040] The optical coupler 1 can reduce the intensity of the reflected light RL. More specifically, the longest length r of each of the multiple fillers P1 satisfies Equation 1. As a result, scattering caused by a portion of the light L emitted from the optical fiber 5 hitting the filler P1 becomes Rayleigh scattering. The intensity of the scattered light caused by Rayleigh scattering is smaller than the intensity of the scattered light caused by Mie scattering and the intensity of the scattered light caused by the light L hitting a material with a wavelength larger than λ. A portion of the scattered light caused by a portion of the light L emitted from the optical fiber 5 hitting the filler P1 becomes the reflected light RL. Therefore, the optical coupler 1 can reduce the intensity of the reflected light RL.

[0041] Moreover, the optical coupler 1 can further suppress the light emitted from a certain optical fiber from being incident on another optical fiber. More specifically, the distance d between the center of each end face S5 of the plurality of optical fibers 5 and the prism portion incident face S2 along the first direction DIR1 is greater than 0 and smaller than the distance p between the centers of the end faces S5 of two adjacent optical fibers 5 along the third direction DIR3. As a result, the distance between the two adjacent optical fibers 5 becomes greater, so that even if a part of the light L emitted from the optical fiber 51 is reflected in a direction in which the optical fiber 51 is not arranged, the reflected light RL is less likely to be incident on the optical fiber 52 and the optical fiber 53. Therefore, the optical coupler 1 can further suppress the light emitted from a certain optical fiber from being incident on another optical fiber.

[0042] Moreover, the optical coupler 1 can further prevent light emitted from one optical fiber from entering another optical fiber. Description will be made with reference to the drawings. Fig. 8 is an enlarged schematic cross-sectional view of the incident surface S11 and the adjacent optical fiber 5 in Fig. 3. Fig. 9 is a cross-sectional view of the incident surface S11 and the optical fiber 5.

[0043] The distance W that the light L emitted from the end face S5 of the optical fiber 51 travels to reach the end face S5 of the optical fiber 52 is expressed by the following formula 2.

[0044]

number

[0045] Assuming that the beam divergence angle of the light L emitted from the optical fiber 51 is 7 degrees, the beam diameter BD of the reflected light RL at the end face S5 of the optical fiber 52 is expressed by the following formula 3.

[0046]

number

[0047] 9, because the angle θ is an acute angle, the position of the beam center of the reflected light RL at the end face S5 of the optical fiber 52 is shifted in the second direction DIR2 from the center of the end face S5 of the optical fiber 51. This shift distance A is expressed by the following Equation 4.

[0048]

number

[0049] If the shift distance A is equal to or greater than the beam diameter BD of the reflected light RL at the end face S5 of the optical fiber 52, the reflected light RL does not reach the end face S5 of the optical fiber 52 and is not incident on the optical fiber 52. In other words, the condition under which the reflected light RL does not enter the optical fiber 52 is expressed by the following formula 5.

[0050]

number

[0051] Here, if it is assumed that the prism portion entrance surface S2 and the end surface S5 of the optical fiber 5 are close to each other, the second term on the right side of Equation 5 can be regarded as 0. The angle θ that satisfies the condition that the reflected light RL is not incident on the optical fiber 52 is greater than 0 degrees and equal to or less than 86.5 degrees. Therefore, when the angle θ is an acute angle, it is preferable that the angle θ is greater than 0 degrees and equal to or less than 86.5 degrees. As a result, the optical coupler 1 can further prevent the light emitted from one optical fiber from being incident on another optical fiber.

[0052] [First Modification] [Structure of optical coupler 1a] An optical coupler 1a according to a first modified example of the present invention will be described below. Fig. 10 is a cross-sectional view of the optical coupler 1a and an optical fiber 5. Note that the second side wall portion 22 and the third side wall portion 23 are omitted in Fig. 10. Note that, for the optical coupler 1a according to the first modified example, only the parts different from the optical coupler 1 according to the first embodiment will be described, and the rest will be omitted.

[0053] In this modification, the angle θ between the prism portion entrance surface S2 and the first direction DIR1 is an obtuse angle when viewed in the third direction DIR3. More specifically, in this modification, the angle θ between the prism portion entrance surface S2 and the first direction DIR1 is greater than 90 degrees and less than 180 degrees in a counterclockwise direction when viewed in the third direction DIR3. In this modification, the angle θ is 93.5 degrees. Note that when the angle θ is an obtuse angle, it is preferable that the angle θ be greater than or equal to 93.5 degrees and less than 180 degrees in a counterclockwise direction.

[0054] The optical coupler 1a as described above also provides the same effects as the optical coupler 1.

[0055] [Second modified example] [Structure of photoelectric conversion circuit module 10] Hereinafter, a photoelectric conversion circuit module 10 according to a second modified example will be described with reference to the drawings. Fig. 11 is a perspective view of the photoelectric conversion circuit module 10 and an optical fiber 5. In Fig. 11, reference symbols are given only to representative optical couplers 1, optical fibers 5, and optical waveguides OW among the multiple optical couplers 1, multiple optical fibers 5, and multiple optical waveguides OW. Fig. 12 is a BB cross-sectional view of the photoelectric conversion circuit module 10 and the optical fiber 5.

[0056] As shown in FIG. 11, the photoelectric conversion circuit module 10 includes a plurality of optical couplers 1, a substrate 11, and an optical conversion circuit 12. The plurality of optical couplers 1 and the optical conversion circuit 12 are mounted on the substrate 11. The optical conversion circuit 12 is disposed at the center of the substrate 11 when viewed in the second direction DIR2. The plurality of optical couplers 1 are disposed around the optical conversion circuit 12 when viewed in the second direction DIR2. Each of the plurality of optical fibers 5 is fixed to the optical fiber fixing portion 4 of each of the plurality of optical couplers 1. The number of optical couplers 1 is not limited to a plurality, and may be one. The optical conversion circuit 12 does not have to be disposed at the center of the substrate 11 when viewed in the second direction DIR2. The plurality of optical couplers 1 does not have to be disposed around the optical conversion circuit 12 when viewed in the second direction DIR2. The photoelectric conversion circuit module 10 may include an optical coupler 1a instead of the optical coupler 1.

[0057] The substrate 11 has a plate shape having two main surfaces aligned in the second direction DIR2. However, as shown in Fig. 12, an optical waveguide OW and a mirror M are provided inside the substrate 11. The optical waveguide OW is provided between the photoelectric conversion circuit 12 and each of the multiple optical couplers 1. The mirror M is provided in the second direction DIR2 from the reflecting portion 3. The light L emitted from the photoelectric conversion circuit 12 passes through the optical waveguide OW.

[0058] The optical couplers 1 are mounted on one of the two main surfaces of the substrate 11 that is located in the opposite direction to the second direction DIR2. More specifically, the mounting surface S22 is mounted on the one of the two main surfaces of the substrate 11 that is located in the opposite direction to the second direction DIR2.

[0059] The photoelectric conversion circuit 12 is mounted on one of the two main surfaces of the substrate 11 that is located in the opposite direction to the second direction DIR2. The photoelectric conversion circuit 12 converts the light emitted from the optical coupler 1 into an electric signal, or converts the electric signal into light that enters the optical coupler 1. A case in which the photoelectric conversion circuit 12 converts the light emitted from the optical coupler 1 into an electric signal will be described.

[0060] The light L emitted from any one of the five optical fibers 5 enters the incident surface S11 of the optical coupler 1, and the traveling direction is changed from the first direction DIR1 to the second direction DIR2 by the optical coupler 1, and the light L is emitted from the exit surface S12 of the optical coupler 1. The light L emitted from the exit surface S12 of the optical coupler 1 travels in the second direction DIR2 in the optical waveguide OW. The light L traveling in the second direction DIR2 in the optical waveguide OW is reflected by the mirror M. As a result, the traveling direction of the light L is changed from the second direction DIR2 to the first direction DIR1. The light L then enters the photoelectric conversion circuit 12. The photoelectric conversion circuit 12 converts the light L incident on the photoelectric conversion circuit 12 into an electrical signal.

[0061] The above-described photoelectric conversion circuit module 10 also provides the same effects as the optical coupler 1 .

[0062] [Third modified example] [Structure of photoelectric conversion circuit module 10a] Hereinafter, a photoelectric conversion circuit module 10a according to the third modification will be described with reference to the drawings. Fig. 13 is a perspective view of the photoelectric conversion circuit module 10a and an optical fiber 5. In Fig. 13, reference symbols are given only to representative optical couplers 1 and optical fibers 5 among the multiple optical couplers 1 and the multiple optical fibers 5. Regarding the photoelectric conversion circuit module 10a according to the third modification, only the parts different from the photoelectric conversion circuit module 10 according to the second modification will be described, and the rest will be omitted.

[0063] The photoelectric conversion circuit module 10a differs from the photoelectric conversion circuit module 10 in that the substrate 11 is a semiconductor substrate and that the substrate 11 includes a plurality of light emitting sections 13. Note that the number of light emitting sections 13 is not limited to a plurality and may be one.

[0064] Each of the light emitting units 13 is, for example, a surface light emitting element formed on one of the two main surfaces of the substrate 11, which is located in the opposite direction to the second direction DIR2. Each of the light emitting units 13 is, for example, a Vertical Cavity Surface Emitting Laser (VCSEL). Each of the light emitting units 13 emits light L based on an electrical signal generated by the photoelectric conversion circuit 12. The light L emitted from each of the light emitting units 13 is incident on each of the optical fibers 5 via each of the optical couplers 1.

[0065] The above-described photoelectric conversion circuit module 10a also provides the same effects as the photoelectric conversion circuit module 10.

[0066] [Fourth Variation] [Structure of optical transceiver 100] The optical transceiver 100 will be described below with reference to the drawings. Fig. 14 is a perspective view of the optical transceiver 100 and the optical fibers 5. Note that in Fig. 14, only a representative optical fiber 5 among the five optical fibers 5 is given a reference symbol. Note that for the optical transceiver 100 according to the fourth modification, only the parts that are different from the photoelectric conversion circuit module 10a according to the third modification will be described, and the rest will be omitted.

[0067] The optical transceiver 100 differs from the photoelectric conversion circuit module 10a in that the optical transceiver 100 has one optical coupler 1 and one light emitting unit 13.

[0068] The light L emitted from the light emitting unit 13 is incident on each of the five optical fibers 5 via the optical coupler 1, or the light L emitted from each of the five optical fibers 5 is incident on the photoelectric conversion circuit 12 via the optical coupler 1.

[0069] The optical transceiver 100 as described above also provides the same effects as the photoelectric conversion circuit module 10a.

[0070] [Other embodiments] The optical coupler according to the present invention is not limited to the optical coupler 1 and the optical coupler 1a, and may be modified within the scope of the invention. Furthermore, the structures of the optical coupler 1 and the optical coupler 1a may be combined in any manner.

[0071] The photoelectric conversion circuit module according to the present invention is not limited to the photoelectric conversion circuit module 10 and the photoelectric conversion circuit module 10a, and may be modified within the scope of the present invention. Furthermore, the structures of the photoelectric conversion circuit module 10 and the photoelectric conversion circuit module 10a may be combined in any manner.

[0072] The optical transceiver according to the present invention is not limited to the optical transceiver 100, and can be modified within the scope of the gist thereof.

[0073] The present invention has the following configuration.

[0074] (1) An optical coupler integrally formed from a material including glass and a filler mixed in the glass, an optical fiber fixing portion that fixes each of a plurality of optical fibers that emit light in a first direction; an incident surface on which the light emitted from any one of the plurality of optical fibers is incident; a reflecting surface that changes a traveling direction of the light incident on the incident surface from the first direction to a second direction perpendicular to the first direction; an exit surface that outputs the light, the direction of which has been changed by the reflecting surface, in the second direction; It is equipped with the plurality of optical fibers are arranged in a third direction perpendicular to the first direction and the second direction, a plurality of condensing lens portions are provided on the reflecting surface to condense the light traveling in the first direction and reflect the light toward the second direction, The plurality of condenser lens portions are aligned in the third direction, When viewed in the third direction, an angle between the incident surface and the first direction is an acute angle or an obtuse angle. Optical coupler.

[0075] (2) When the longest length of the filler is r and the wavelength of the light is λ, the following formula 1 is satisfied: 13. The optical coupler according to claim 12 .

[0076]

number

[0077] (3) Each of the plurality of optical fibers has an end surface from which the light is emitted, a distance along the first direction between a center of the end face of each of the plurality of optical fibers and the incident surface is greater than 0 and smaller than a distance along the third direction between centers of the end faces of two adjacent ones of the optical fibers; An optical coupler as described in (1) or (2).

[0078] (4) When viewed in the third direction, an angle between the incident surface and the first direction is greater than 0 degrees and less than 86.5 degrees, or is greater than 93.5 degrees and less than 180 degrees, in a counterclockwise direction. An optical coupler according to any one of (1) to (3).

[0079] (5) An optical coupler according to any one of (1) to (4); A substrate; a photoelectric conversion circuit mounted on the substrate; The photoelectric conversion circuit converts an electrical signal into light incident on the optical coupler, or converts light emitted from the optical coupler into an electrical signal. Photoelectric conversion circuit module.

[0080] (6) the substrate is a semiconductor substrate and includes a light emitting portion that emits light, The optical coupler is mounted on the substrate. The photoelectric conversion circuit module according to (5).

[0081] (7) A photocoupler according to any one of (1) to (4), Optical transceiver. [Explanation of symbols]

[0082] 1,1a: Optical coupler 2: Holding part 3:Reflector 4: Optical fiber fixing part 5, 51, 52, 53: Optical fiber 10, 10a: Photoelectric conversion circuit module 11: Substrate 12: Photoelectric conversion circuit 13: Light output section 21: First side wall portion 22: Second side wall portion 23: Third side wall 24: Bottom 31: Prism section 32: Condenser lens section 100: Optical transceiver A: Displacement distance A1,A2:Area BD: Beam diameter DIR1: 1st direction DIR2:Second direction DIR3: Third direction G:Groove L:Light M: Mirror M1: Glass OW: Optical Waveguide P1: Filler RL: Reflected light S1, S5: End face S11:Incidence surface S12: Output surface S2: Prism entrance surface S22: Mounting surface S3: Prism part reflective surface S4: Prism part exit surface d,p: distance θ: Angle

Claims

1. An optical coupler integrally formed from a material including glass and a filler mixed in the glass, an optical fiber fixing portion that fixes each of a plurality of optical fibers that emit light in a first direction; an incident surface on which the light emitted from any one of the plurality of optical fibers is incident; a reflecting surface that changes a traveling direction of the light incident on the incident surface from the first direction to a second direction perpendicular to the first direction; an exit surface that outputs the light, the traveling direction of which has been changed by the reflecting surface, in the second direction; Equipped with the plurality of optical fibers are arranged in a third direction perpendicular to the first direction and the second direction, a plurality of condensing lens portions are provided on the reflecting surface to condense the light traveling in the first direction and reflect the light toward the second direction, The plurality of condenser lens portions are aligned in the third direction, When viewed in the third direction, an angle between the incident surface and the first direction is an acute angle or an obtuse angle. Optical coupler.

2. When the longest length of the filler is r and the wavelength of the light is λ, the following formula 1 is satisfied:

2. The optical coupler of claim 1. [0010]

3. Each of the plurality of optical fibers has an end surface from which the light is emitted, a distance along the first direction between a center of the end face of each of the plurality of optical fibers and the incident surface is greater than 0 and smaller than a distance along the third direction between centers of the end faces of two adjacent optical fibers; 3. The optical coupler according to claim 1 or 2.

4. When viewed in the third direction, an angle between the incident surface and the first direction is greater than 0 degrees and less than 86.5 degrees, or is greater than 93.5 degrees and less than 180 degrees, in a counterclockwise direction.

3. The optical coupler according to claim 1 or 2.

5. An optical coupler according to claim 1 or 2; A substrate; a photoelectric conversion circuit mounted on the substrate; The photoelectric conversion circuit converts an electrical signal into light incident on the optical coupler, or converts light emitted from the optical coupler into an electrical signal. Photoelectric conversion circuit module.

6. the substrate is a semiconductor substrate and includes a light emitting portion that emits light, The optical coupler is mounted on the substrate. The photoelectric conversion circuit module according to claim 5 .

7. A photocoupler according to claim 1 or 2, Optical transceiver.

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