JP6133028B2 - Optical fiber, optical module, and optical module manufacturing method - Google Patents

Description

  The present invention relates to an optical fiber optically coupled to a light emitting element, an optical module including an optical fiber optically coupled to each other and a light emitting element, and a method for manufacturing the optical module.

  When the optical fiber and the light emitting element are coupled to each other, if the positional deviation between the two occurs, the coupling efficiency is significantly reduced. The following Patent Document 1 discloses an optical module capable of easily aligning an optical fiber and an optical element. In the optical module disclosed in Patent Document 1, a fusion layer is disposed on the surface of a substrate on which a surface emitting laser is formed. In the state which joined the surface of the melt | fusion layer and the end surface of an optical fiber, both are melt | fused.

  Convex portions are formed on the surface of the fusion layer. The optical fiber has a fitting portion having a shape that fits with the convex portion of the fusion layer on the end surface thereof. By fitting the fitting portion of the optical fiber and the convex portion of the fusion layer, both can be easily aligned.

JP 2002-107581 A

  If the convex portion formed in the fusion layer is deviated from the position of the surface emitting laser, the position of the optical fiber with respect to the surface emitting laser is deviated from the target position.

  An object of the present invention is to provide an optical fiber in which the positional deviation between the optical element and the optical fiber hardly occurs. Another object of the present invention is to provide an optical module in which positional deviation between an optical element and an optical fiber hardly occurs. Still another object of the present invention is to provide a method of manufacturing an optical module in which the positional deviation between the optical element and the optical fiber hardly occurs.

According to one aspect of the invention,
With multiple cores,
A clad covering the core;
A core identifying marker that does not overlap the core but is located at a position off the center of the cladding;
Corresponding to each of the plurality of cores, a recess formed in the end surface ;
An alignment recess disposed at a position corresponding to the core identification marker ;
Each mesa portion of a plurality of light emitting elements formed on the same substrate is inserted into the recess, and light emitted from the top surface of the mesa portion enters at least the bottom surface of the recess, thereby entering the core. The light emitting element is optically coupled ;
The core is disposed at a position that is rotationally symmetric with respect to the center axis of the cladding, and an optical fiber is provided in which the core identification marker is disposed at a position that breaks the rotational symmetry of the core. .

According to another aspect of the invention,
A light emitting element including a plurality of mesas that emit light from the upper surface;
An optical fiber optically coupled to the light emitting element;
The optical fiber is
With multiple cores,
Clad,
A plurality of recesses formed on the end face;
In the cross section of the optical fiber, a core identification marker arranged at a position not overlapping the core;
An alignment recess formed at the position of the marker on the end face of the optical fiber;
The light emitting element further includes a convex portion inserted into the alignment concave portion,
A plurality of the mesa portions of the light emitting element are inserted into the plurality of concave portions, and light emitted from the light emitting element is incident on the bottom surface of the concave portion, so that the light emitting element is optically coupled to the core. An optical module is provided.

According to yet another aspect of the invention,
A cladding, and a plurality of cores, from the end face of an optical fiber having a core identification markers, in the core and fast conditions than the etching rate of the etching rate of the core identification markers said cladding, said core, said core identification Forming a recess in a portion corresponding to the core by etching the marker and the clad , and forming a positioning recess in a position corresponding to the core identification marker ;
The mesa portion of the light emitting element including a plurality of mesa portions emitting light from the upper surface and the alignment convex portion is inserted into the concave portion of the optical fiber, and the alignment convex portion is used as the alignment concave portion. Inserting , and
The mesa portion is inserted into the recess, with the protrusion for the positioning is inserted into the recess for the positioning, possess a step of fixing the optical fiber to the light emitting element,
The plurality of cores are arranged at positions that are rotationally symmetric about the center axis of the cladding, and the core identification marker is arranged at a position that breaks the rotational symmetry of the cores. A method is provided.

  By inserting the mesa portion into the recess of the optical fiber, the light emitting element and the optical fiber can be easily aligned. After the alignment is completed, the positional deviation between the two hardly occurs.

1A is a perspective view of the vicinity of an end face of an optical fiber used in the optical module according to the first embodiment, FIG. 1B is a front view of the optical module according to the first embodiment, and FIG. 1C is an alternate long and short dash line 1C in FIG. It is sectional drawing in -1C. FIG. 2 is a cross-sectional view of the optical fiber according to Example 1 and a light emitting element optically coupled thereto. FIG. 3A is a cross-sectional view of the vicinity of the end of the optical fiber for explaining a method of forming a recess in the optical fiber, and a graph showing the etching rate distribution. FIGS. 3B and 3C are the etching rates of the core, respectively. 3B is a cross-sectional view of the vicinity of the end of the optical fiber when the etching rate is slower and faster than the etching rate of FIG. 3A. 4A is a plan view of a light-emitting element used in the optical module according to Embodiment 1, and FIG. 4B is a cross-sectional view taken along one-dot chain line 4B-4B in FIG. 4A. 5A is a front view of an end face of an optical fiber used in the optical module according to the second embodiment, and FIG. 5B is a cross-sectional view of the optical module taken along one-dot chain line 5B-5B in FIG. 5A. FIG. 6 is a plan view of a light-emitting element and its substrate used in the optical module according to the second embodiment. 7A is a front view of an end face of an optical fiber used in the optical module according to Embodiment 3, and FIG. 7B is a cross-sectional view of the optical module taken along one-dot chain line 7B-7B in FIG. 7A.

[Example 1]
FIG. 1A shows a perspective view of the vicinity of the end face of the optical fiber 10 used in the optical module according to the first embodiment, and FIG. 1B shows a front view of the optical fiber 10. The side surface of the core 11 is covered with the cladding 12. The side surface of the clad 12 is covered with a coating layer 13.

FIG. 1C shows a cross-sectional view taken along one-dot chain line 1 </ b> C- 1 </ b> C in FIG. 1B, that is, a cross-sectional view in the vicinity of the end including the central axis of the optical fiber 10. The side surface of the core 11 is covered with the cladding 12. A recess 15 is formed on one end face 14 of the optical fiber 10. The recess 15 is formed at the position of the core 11. For this reason, the bottom surface of the recess 15 is constituted by the end surface of the core 11. Further, the clad 12 is exposed on the side surface of the recess 15.

  FIG. 2 is a sectional view of the optical module according to the first embodiment. A mesa portion 20 is formed on the surface of the support substrate 30. The mesa unit 20 constitutes a part of the light emitting element 21. The light emitting element 21 emits light from the upper surface of the mesa unit 20. As the light emitting element 21, for example, a surface emitting laser element, a light emitting diode, or the like is used.

  The mesa unit 20 is inserted (fitted) into the recess 15 of the optical fiber 10. A transparent medium 16 is filled between the surface of the mesa unit 20 and the inner surface of the recess 15. Here, “transparent” in the transparent medium means transparent to the light emitted from the light emitting element 21. The transparent medium 16 is also filled between the upper surface of the substrate 30 and the end surface 14 of the optical fiber 10. With reference to the upper surface of the support substrate 30, the end surface 14 of the optical fiber 10 is fixed at a position lower than the upper surface of the mesa unit 20. The light emitted from the light emitting element 21 passes through the top surface of the mesa unit 20 and the transparent medium 16 and enters the bottom surface of the recess 15. Thereby, the light emitting element 21 is optically coupled to the core 11.

  The difference between the refractive index of the transparent medium 16 and the refractive index of the core 11 is smaller than the difference between the refractive index of the atmosphere and the refractive index of the core 11. Thereby, the light emitted from the light emitting element 21 can be efficiently incident on the core 11. For the transparent medium 16, for example, matching oil, a transparent adhesive, or the like is used.

  With reference to FIG. 3A, the method of forming the recessed part 15 is demonstrated. FIG. 3A shows a cross-sectional view near the end face of the optical fiber 10 and a graph of the etching rate distribution in the radial direction. In FIG. 3A, the radius of the core 11 is r1, and the radius of the outer peripheral surface of the clad 12 is r2. The recess 15 can be formed by etching the optical fiber 10 from its end face. The end surface of the optical fiber 10 before forming the recess 15 is a flat surface as shown by a solid line. The end face 14 after etching is indicated by a broken line.

  The etching rates of the core 11 and the clad 12 under the etching conditions for forming the recess 15 are represented by R2 and R1, respectively. By etching the optical fiber 10 under the etching conditions satisfying R2> R1, the portion of the core 11 is dug deeper relatively, so that the recess 15 can be formed. For this etching, for example, a buffered hydrogen fluoride aqueous solution (buffered hydrofluoric acid) can be used.

  Since the etching rate in the length direction of the optical fiber is generally faster than the etching rate in the lateral direction (radial direction), the recess 15 having an isosceles trapezoidal cross section as shown in FIG. It is formed. Thus, by forming the recess 15 using the difference in etching rate between the core 11 and the cladding 12, the position of the recess 15 can be self-aligned with the core 11. The formation of the recess 15 is not limited to a technique using etching, but may be formed by performing a process of cutting only the core 11 portion.

  Further, the depth of the recess 15 may be shallow enough that the top surface of the mesa portion contacts the bottom surface of the recess 15 when the mesa portion of the light emitting element is inserted into the recess 15, or deep enough not to contact. Also good.

  When the depth of the recess 15 is such that the upper surface of the mesa portion contacts the bottom surface of the recess 15, almost all of the light emitted from the upper surface of the mesa portion enters the core 11 of the optical fiber 10.

Even when the depth of the recess 15 is such that the upper surface of the mesa portion does not contact the bottom surface of the recess 15, the light spreads when the light emitted from the light emitting element reaches the bottom surface of the recess 15. If is not large, most of the emitted light can be incident on the core 11 of the optical fiber 10.

  Further, the outer periphery of the bottom surface of the recess 15 formed by etching and the outer periphery of the core 11 do not necessarily coincide with each other. That is, when the etching rate R2 is relatively slow, the etching of the core 11 is difficult to proceed, so that the diameter of the bottom surface of the recess 15 may be smaller than the diameter of the core 11 as shown in FIG. Further, when the etching rate R2 is relatively fast, as shown in FIG. 3C, the etching proceeds also in the direction of the side wall of the clad 12, so that the diameter of the bottom surface of the recess 15 is larger than the diameter of the core 11. There is also. Even when the etching rate is as shown in FIG. 3A, the end shape as shown in FIG. 3B or FIG. 3C can be obtained by appropriately adjusting the etching time.

  FIG. 4A shows a plan view of the light emitting element 21 (FIG. 2). A circular upper distributed Bragg reflection (upper DBR) film 53 is formed inside the mesa portion 20 having a substantially circular planar shape. The upper DBR film 53 is surrounded by a ring-shaped upper electrode 56. A lead line 57 extends from the upper electrode 56 in the radial direction (rightward in FIG. 4A). Leader line 57 extends to the outside of mesa portion 20. A ring-shaped lower electrode 55 is formed so as to surround the mesa unit 20. The lower electrode 55 is cut at the intersection between the lead wire 57 of the upper electrode 56 and the lower electrode 55, and insulation between the lower electrode 55 and the lead wire 57 is ensured.

  FIG. 4B is a cross-sectional view taken along one-dot chain line 4B-4B in FIG. 4A. On a substrate 40 made of n-type GaAs having a plane orientation (001), a lower distributed Bragg reflection (lower DBR) film 41 and an n-type contact layer 42 are formed in this order. A mesa portion 20 is formed in a partial region of the n-type contact layer 42.

  The mesa unit 20 includes an n-type cladding layer 43, an active layer 44, a p-type cladding layer 45, a lower composition gradient layer 46, a current confinement layer 47, an upper composition gradient layer 48, and a p-type spacer layer, which are sequentially stacked from the substrate side. 49, a p-type high conductivity layer 50, a p-type spacer layer 51, and a p-type contact layer 52. An upper DBR film 53 is formed on a partial region of the p-type contact layer 52.

  The lower electrode 55 is in ohmic contact with the n-type contact layer 42. The upper electrode 56 is in ohmic contact with the p-type contact layer 52. The region where the lower electrode 55 is not formed in the n-type contact layer 42, the side surface of the mesa unit 20, and the region where neither the upper DBR film 53 nor the upper electrode 56 is formed on the upper surface of the mesa unit 20 54. A lead line 57 continuous to the upper electrode 56 is formed on the insulating film 54. The lead line 57 passes through the side surface of the mesa unit 20 and is led out to a region where the mesa unit 20 is not formed. The substrate 40, the lower DBR film 41, and the n-type contact layer 42 correspond to the support substrate 30 shown in FIG. 2B.

  The lower DBR film 41 includes a plurality of low refractive index layers and a plurality of high refractive index layers that are alternately stacked. For example, AlGaAs is used for the low refractive index layer, and GaAs is used for the high refractive index layer. The lower DBR film 41 reflects light in the emission wavelength region of the active layer 44.

  The n-type contact layer 42 is made of, for example, n-type GaAs, and the n-type cladding layer 43 is made of, for example, n-type GaAs.

  The active layer 44 has a multiple quantum well structure in which three well layers and two barrier layers are alternately stacked. The composition and film thickness of the well layer and the barrier layer are determined by a normal design method based on the target oscillation wavelength. For example, a GaInAs semiconductor material is used for the well layer. For example, GaAs is used for the well layer.

  The p-type cladding layer 45 is made of, for example, p-type AlGaAs.

  The configurations of the lower composition gradient layer 46, the current confinement layer 47, and the upper composition gradient layer 48 will be described. The current confinement layer 46 includes a current passage portion 47A and a current blocking portion 47B. The current passage portion 47A is disposed at the center of the mesa portion 20 in plan view, and the current blocking portion 47B is disposed so as to surround the current passage portion 47A. The current passage portion 47A is made of AlGaAs. The current blocking portion 47B is formed by selectively oxidizing AlGaAs. The diameter of the current passage portion 47A is, for example, 4 μm to 15 μm.

  The lower composition gradient layer 46 and the upper composition gradient layer 48 are formed of p-type AlGaAs. The Al composition ratio of the lower composition gradient layer 46 and the upper composition gradient layer 48 approaches the Al composition ratio of the current passage portion 47A as it approaches the current confinement layer 47 in the stacking direction. The current confinement layer 47 concentrates carriers injected from the upper electrode 56 into the active layer 44 in a region immediately below the current passage portion 47A.

  The p-type spacer layers 49 and 51 are made of, for example, p-type AlGaAs. The p-type high conductivity layer 50 is made of, for example, p-type AlGaAs. The p-type high conductivity layer 50 provides a path for transporting carriers injected from the upper electrode 56 in the in-plane direction. By disposing the p-type high conductivity layer 50, the carriers injected from the upper electrode 56 can be more efficiently concentrated on the current passage portion 47A.

  The p-type contact layer 52 is made of, for example, p-type GaAs.

The upper DBR film 53 includes a plurality of low refractive index layers and a plurality of high refractive index layers that are alternately stacked. For example, SiO ₂ is used for the low refractive index layer, and SiN is used for the high refractive index layer. Similar to the lower DBR film 41, the upper DBR film 53 reflects light in the emission wavelength region of the active layer 44.

  In the first embodiment, as shown in FIG. 2, when the optical fiber 10 and the light emitting element 21 are optically coupled, the mesa portion 20 is inserted into the concave portion 15 so that they can be easily aligned. be able to. Since the active layer 44 (FIG. 4B) is located in the mesa portion 20, the active layer 44 that is a light emitting portion is aligned with the core 11 by inserting the mesa portion 20 into the recess 15.

  After the alignment between the optical fiber 10 and the light emitting element 21 is completed, the light emitting element 21 is fixed to the optical fiber 10. The light emitting element 21 and the optical fiber 10 can be fixed by loading them in a package. Since the mesa portion 20 is inserted into the concave portion 15, it is difficult for the optical fiber 10 and the light emitting element 21 to be misaligned. For this reason, the workability | operativity of the loading to a package can be improved.

  In order to facilitate the insertion of the mesa unit 20 into the recess 15, the figure obtained by projecting the upper surface of the mesa unit 20 of the light emitting element 21 onto the cross section perpendicular to the central axis of the optical fiber 10 is the same as the bottom surface of the recess 15. It is preferable to be included in the figure projected onto the cross section. As an example, the diameter of the upper surface of the mesa portion 20 may be made smaller than the diameter of the bottom surface of the recessed portion 15 of the etched optical fiber 10.

  Furthermore, in Example 1, the light emitting surface (the upper surface of the mesa unit 20) of the light emitting element 21 is opposed to the end surface of the core 11 so as to increase the light coupling efficiency between the two. Can do.

[Example 2]
FIG. 5A is a front view of the end face of the optical fiber used in the optical module according to the second embodiment. Hereinafter, differences from the first embodiment will be described, and description of the same configuration will be omitted. In the optical fiber 10 according to the second embodiment, a plurality of cores 11 are arranged in a clad 12. That is, the optical fiber 10 according to the second embodiment is a so-called multicore fiber. As an example, the optical fiber 10 according to the second embodiment includes seven cores 11. One core 11 is arranged at a position that coincides with the central axis of the optical fiber 11, and the other six cores 11 have six-fold rotational symmetry about the central axis in the example shown in FIG. 5A. It is arranged at the position.

  The number of cores 11 may be other than seven. For example, when four cores 11 are arranged, one core 11 is arranged at the position of the central axis of the optical fiber 10, and the other three cores 11 are arranged with the central axis of the optical fiber 10 as the rotation center. You may make it arrange | position in the position used as rotational rotation symmetry. More generally, when (n + 1) cores 11 are arranged, one core 11 is arranged at the position of the central axis of the optical fiber 10, and the other n cores 11 are arranged at the central axis of the optical fiber 10. May be arranged at a position that is n times rotationally symmetric with respect to the rotation center. Here, n is an integer of 2 or more.

  One core 11 is arranged along the central axis of the optical fiber 10, and other cores 11 are arranged not only in a rotationally symmetric position with the central axis of the optical fiber 10 as the rotation center, The form which does not arrange | position the core 11 along the central axis of the fiber 10 may be sufficient. In this case, a plurality of light emitting elements 21 are formed on the surface of the support substrate 30 in correspondence with the arrangement locations of the plurality of cores 11 arranged in the optical fiber 10.

  FIG. 5B shows a cross-sectional view of the optical module taken along one-dot chain line 5B-5B in FIG. 5A. A recess 15 is formed in the end face 14 of the optical fiber 10 corresponding to the core 11. A plurality of light emitting elements 21 are formed on the surface of the support substrate 30. Each of the light emitting elements 21 includes a mesa unit 20. The mesa unit 20 is disposed at a position corresponding to the recess 15 in a state where the substrate 30 is opposed to the end face 14 of the optical fiber 10. The mesa portion 20 is inserted (fitted) into the corresponding recess 15.

  FIG. 6 is a plan view of the light emitting element 21 and the support substrate 30 according to the second embodiment. A plurality of, for example, seven light emitting elements 21 are formed on the surface of the support substrate 30. Each of the light emitting elements 21 has the same structure as the light emitting element 21 according to Example 1 shown in FIGS. 4A and 4B. Each of the light emitting elements 21 includes an upper electrode 56 and a lower electrode 55. A pair of pads 60 and 61 are formed on the surface of the substrate 30 corresponding to the light emitting element 21.

  Leader line 58 connects lower electrode 55 and one pad 60. A lead line 57 connects the upper electrode 56 and the other pad 61. Current is supplied from the pads 60 and 61 to the light emitting element 21.

  Also in Example 2, the alignment between the optical fiber 10 and the light emitting element 21 can be easily performed by inserting the mesa portion 20 (FIG. 5B) into the concave portion 15 (FIG. 5B). Further, since the plurality of cores 11 and the plurality of light emitting elements 21 can be aligned at the same time, the working efficiency can be improved as compared with the configuration in which single core optical fibers are coupled to the light emitting elements one by one. it can.

  The multi-core fiber and the light emitting element according to the second embodiment can be applied to, for example, optical wiring (interconnection) in a computer.

[Example 3]
FIG. 7A is a front view of the end face of the optical fiber used in the optical module according to the third embodiment. Hereinafter, differences from the second embodiment will be described, and description of the same configuration will be omitted. In the optical fiber 10 according to the third embodiment, a core identifying marker 17 is disposed in the clad 12 in addition to the core 11. The core identifying marker 17 is arranged along the axial direction of the optical fiber 10 in the same manner as the core 11. As an example, the core identification marker 17 is formed of the same material as the core 11. Further, the core identifying marker 17 may be formed of holes.

  The seven cores 11 form a pattern that is 6-fold rotationally symmetric in the cross section of the optical fiber 10. The core identifying marker 17 is not overlapped with the core 11 and is disposed at a position off the center of the optical fiber 10. The core identifying marker 17 breaks the rotational symmetry of the arrangement of the cores 11. By recognizing the position of the core identification marker 17, the six cores 11 arranged at the six-fold rotationally symmetric positions can be easily distinguished from each other.

  7B shows a cross-sectional view of the optical module taken along one-dot chain line 7B-7B in FIG. 7A. In addition to the recess 15 corresponding to the core 11, an alignment recess 18 is formed on the end face 14 of the optical fiber 10. The alignment recess 18 is arranged at a position corresponding to the core identification marker 17. When the marker 17 is formed of the same material as that of the core 11, when the recess 15 is formed by etching, the alignment recess 18 is also formed at the same time. When the marker 17 is formed with a hole, when the recess 15 is formed by etching, the cladding 12 in the vicinity of the opening of the hole (near the end face 14 of the optical fiber 10) is etched, thereby aligning the position. A recess 18 is formed.

  On the surface of the support substrate 30 on which the light emitting element 21 is formed, a convex portion 22 for alignment is formed in addition to the mesa portion 20 constituting the light emitting element 21. At the same time as the mesa portion 20 of the light emitting element 21 is inserted into the recess 15, the projection 22 is inserted into the alignment recess 18. By aligning and inserting the convex portion 22 into the alignment concave portion 18, it is possible to easily align the rotation direction of the optical fiber 10 with the substrate 30 on which the plurality of light emitting elements 21 are formed.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Optical fiber 11 Core 12 Cladding 13 Cover layer 14 End face 15 Recess 16 Transparent medium 17 Core identification marker 18 Positioning recess 20 Mesa 21 Light emitting element 22 Positioning convex 30 Support substrate 40 Substrate 41 Lower DBR film 42 n-type contact layer 43 n-type cladding layer 44 active layer 45 p-type cladding layer 46 lower composition gradient layer 47 current confinement layer 48 upper composition gradient layer 49 p-type spacer layer 50 p-type high conductivity layer
51 p-type spacer layer 52 p-type contact layer 53 upper DBR film 54 insulating film 55 lower electrode 56 upper electrode 57 leader line

Claims (10)

With multiple cores,
A clad covering the core;
A core identifying marker that does not overlap the core but is located at a position off the center of the cladding;
Corresponding to each of the plurality of cores, a recess formed in the end surface;
An alignment recess disposed at a position corresponding to the core identification marker;
Each mesa portion of a plurality of light emitting elements formed on the same substrate is inserted into the recess, and light emitted from the top surface of the mesa portion enters at least the bottom surface of the recess, thereby entering the core. The light emitting element is optically coupled;
The core is disposed at a position that is rotationally symmetric about the center axis of the clad, and the core identification marker is disposed at a position that breaks the rotational symmetry of the core.   The light according to claim 1, wherein a figure obtained by projecting the upper surface of the mesa portion of the light emitting element onto a cross section perpendicular to the central axis of the optical fiber is included in a figure obtained by projecting the bottom surface of the concave portion onto the cross section. fiber.   The optical fiber according to claim 1, wherein a bottom surface of the concave portion is constituted by an end surface of the core.   The optical fiber according to any one of claims 1 to 3, wherein the clad is exposed on a side surface of the recess. A light emitting device including at least one mesa portion emitting light from an upper surface, an active layer located in the mesa portion, an upper electrode, and a lower electrode, wherein the upper electrode is in ohmic contact with the upper surface of the mesa portion;
An optical fiber optically coupled to the light emitting element;
The optical fiber is
At least one core;
Clad,
A recess formed on the end face,
An optical module in which the mesa portion of the light emitting element is inserted into the recess, and the light emitted from the light emitting element is incident on the bottom surface of the recess to optically couple the light emitting element to the core. Said optical fiber, said include one other to a plurality of other core of the core comprises in addition to corresponding to said plurality of other core formed on the end face a plurality of other of the recess of the recess,
The light emitting element includes a plurality of mesas,
The optical module according to claim 5, wherein the plurality of mesa portions are accommodated in the plurality of concave portions, respectively.   The optical module according to claim 5, wherein the light emitting element is a surface emitting semiconductor laser element or a light emitting diode.   The optical module according to claim 5, wherein the lower electrode is formed so as to surround the mesa portion. A light emitting element including a plurality of mesas that emit light from the upper surface;
An optical fiber optically coupled to the light emitting element;
The optical fiber is
With multiple cores,
Clad,
A plurality of recesses formed on the end face;
In the cross section of the optical fiber, a core identification marker arranged at a position not overlapping the core;
An alignment recess formed at the position of the marker on the end face of the optical fiber;
The light emitting element further includes a convex portion inserted into the alignment concave portion,
A plurality of the mesa portions of the light emitting element are inserted into the plurality of concave portions, and light emitted from the light emitting element is incident on the bottom surface of the concave portion, so that the light emitting element is optically coupled to the core. Optical module. From the end face of the optical fiber having a cladding, a plurality of cores, and a core identification marker, the core and the core identification are performed under a condition that an etching rate of the core and the core identification marker is faster than an etching rate of the cladding. Forming a recess in a portion corresponding to the core by etching the marker and the clad, and forming a positioning recess in a position corresponding to the core identification marker;
The mesa portion of the light emitting element including a plurality of mesa portions emitting light from the upper surface and the alignment convex portion is inserted into the concave portion of the optical fiber, and the alignment convex portion is used as the alignment concave portion. Inserting, and
Fixing the optical fiber to the light emitting element in a state where the mesa portion is inserted into the recess and the alignment convex portion is inserted into the alignment recess,
The plurality of cores are arranged at positions that are rotationally symmetric about the center axis of the cladding, and the core identification marker is arranged at a position that breaks the rotational symmetry of the cores. Method.

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