JP2015222292A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module capable of improving the yield rate by arranging a reflection film forming area to prevent peel-off of the reflection film from a baseplate.SOLUTION: The optical module includes: an internal waveguide 16 which is formed in a waveguide forming groove 1a on a baseplate 1; and a mirror part 15 for changing an optical path. The optical module includes optical elements 12a and 12b which are mounted on the surface of the baseplate 1 so as to face the mirror part 15, and each of which emits an optical signal to a core part 17 of the internal waveguide 16 via the mirror part 15 or receives an optical signal from the core part 17 of the internal waveguide 16 via the mirror part 15. The mirror part 15 is constituted of a reflection film 15a which is formed over an inclined plane of the front end face of the waveguide forming groove 1a. The reflection film 15a extends from the upper face of the baseplate 1 in a length direction of the internal waveguide 16.

Description

  The present invention relates to an optical module including an optical element.

  Conventionally, as shown in FIG. 13A, the optical module includes an internal waveguide 16 provided in a first groove (waveguide forming groove) 1a formed on the surface of the substrate 1, and the first groove 1a. And an optical path changing mirror portion 15 formed on the front end surface of the optical path. Further, the optical element 12 is provided that emits an optical signal to the core portion 17 of the internal waveguide 16 via the mirror portion 15 or receives an optical signal from the core portion 17 of the internal waveguide 16 via the mirror portion 15. ing.

  Furthermore, an optical fiber (external waveguide) 2 having a fiber core portion 21 provided in the second groove 1b formed on the surface of the substrate 1 and optically coupled to the core portion 17 of the internal waveguide 16 is provided. (See Patent Document 1).

  By the way, when the optical module is operating, the mirror portion 15 and the synthetic resin internal waveguide 16 may generate heat due to light absorption. In particular, when the optical element 12 is a light-emitting element, the vicinity of the mirror portion 15 near this is before the light spreads, and thus the heat density tends to increase because the light power density is high.

  In such an optical module, if the transmission distance is short or low, the power density of the light from the optical element 12 is low, so that the heat generation temperature of the mirror portion 15 and the internal waveguide 16 in the vicinity thereof is so high as to be a problem. Don't be. However, in the case of long distance and high-speed transmission, higher light output is required to ensure transmission reliability, and the heat generation temperature of the mirror unit 15 and the internal waveguide 16 in the vicinity thereof is increased accordingly.

  Therefore, there is a possibility that the core portion 17 is peeled off from the substrate 1 due to the stress caused by the temperature rise of the mirror portion 15 and the internal waveguide 16 in the vicinity thereof.

  Therefore, as shown in FIG. 13B, a device has been proposed in which the front end 17a of the core portion 17 is retracted from the mirror portion 15 to suppress the temperature rise so that peeling does not easily occur.

JP 2013-3549 A

  However, when the mirror part 15 is configured by forming a reflective film (for example, an Au film) for improving the reflectance on the inclined surface of the substrate 1, due to the stress caused by the temperature rise of the mirror part 15, The reflective film is easily peeled from the substrate. Therefore, there has been a problem that the module yield rate is lowered.

  13B is drawn so as to be formed between the upper end of the inclined surface of the substrate 1 and the vicinity of the front end 17a of the retracted core portion 17. However, the actual situation is that sufficient research and disclosure have not been made on the formation range of the reflective film itself.

  The present invention has been made to solve the above problems, and by adding a device to the formation range of the reflective film, an optical module that makes it difficult to peel the reflective film from the substrate and can improve the yield rate is provided. It is intended to provide.

  In order to solve the above-described problems, the present invention provides an internal waveguide provided in a waveguide forming groove formed on the surface of a substrate, and an optical path conversion mirror portion formed on the tip surface of the groove. It has. It is mounted on the surface of the substrate so as to face this mirror part, and emits an optical signal to the core part of the internal waveguide through the mirror part, or an optical signal from the core part of the internal waveguide through the mirror part. It is an optical module provided with the optical element which receives light. The mirror portion is configured by forming a reflective film on an inclined surface that is a tip surface of the waveguide forming groove, and the reflective film extends from the upper surface of the substrate in the length direction of the internal waveguide. Be present.

  According to the present invention, a reflective film (for example, an Au film) is formed on the inclined surface that is the tip surface of the waveguide forming groove to form a mirror portion. The formation range is set so as to extend in the vertical direction.

  Therefore, the reflection film is not only in close contact with the inclined surface but also in close contact with the upper surface of the substrate, so that the reflection film is difficult to peel off from the substrate and the yield rate of the optical module is improved. Become.

  The front end of the core part may be set at a position retracted from the mirror part, and the reflective film may be extended to the vicinity not overlapping the front end of the core part.

  According to this configuration, the temperature rise is suppressed by retracting the front end of the core portion from the mirror portion, and the core portion is less likely to be peeled off.

  The reflective film may be configured to extend to near the mirror bottom of the waveguide forming groove.

  According to this configuration, the formation range of the reflective film is set so as to extend to the vicinity of the mirror bottom of the waveguide forming groove. Therefore, the reflective film is more difficult to peel off from the substrate, and the yield rate of the optical module is further improved. In addition, in combination with the fact that the reflective film is difficult to peel off from the substrate, the core part is also difficult to peel from the substrate when the core part is overlapped on the reflective film. The module yield rate is improved.

  The reflective film may be configured to extend to the vicinity of the front end of the groove portion of the waveguide forming groove.

  According to this configuration, the formation range of the reflective film is set so as to extend to the vicinity of the front end of the groove portion of the waveguide forming groove. Therefore, the reflective film is more difficult to peel off from the substrate, and the yield rate of the optical module is further improved.

  The reflective film may be configured to extend further to the rear than the front end of the groove portion of the waveguide forming groove.

  According to this configuration, the formation range of the reflective film is set so as to extend further to the rear than the front end of the groove portion of the waveguide forming groove. Therefore, the reflective film is more difficult to peel off from the substrate, and the yield rate of the optical module is further improved.

  The reflective film may be configured to be narrower than the width of the core portion of the internal waveguide.

  According to this configuration, the reflective film is set in a formation range narrower than the width of the core portion of the internal waveguide. Therefore, coupled with the fact that the reflective film is difficult to peel off from the substrate, both side portions of the core portion do not overlap on the reflective film, so the core portion itself is also difficult to peel off from the substrate. The rate will improve.

  The reflection film may be configured to have a width in the vicinity of the upper end of the waveguide forming groove.

  According to this configuration, the reflective film has a formation range set to a width near the upper end of the waveguide forming groove. Therefore, the reflective film is more difficult to peel off from the substrate, and the yield rate of the optical module is further improved. Combined with the fact that the reflective film is difficult to peel off from the substrate, the clad part and the core part are overlapped on the reflective film. As a result, the clad part and the core part are also difficult to peel from the substrate. From the point of view, the yield rate of the optical module is improved.

  The reflective film may be configured to be wider than the upper end width of the waveguide forming groove.

  According to this configuration, the formation range of the reflective film is set wider than the upper end width of the waveguide forming groove. Therefore, the reflective film is more difficult to peel off from the substrate, and the yield rate of the optical module is further improved.

  According to the present invention, by devising the formation range of the reflective film, it is difficult to peel the reflective film from the substrate, and the yield rate can be improved.

1 is a schematic side view of an optical module according to the present invention. It is an internal waveguide of 1st Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a), (c) is the II-II sectional view taken on the line (a). It is an internal waveguide of 2nd Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a). It is an internal waveguide of 3rd Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a). It is an internal waveguide of 4th Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a), (c) is the II-II sectional view taken on the line of (a). It is an internal waveguide of 5th Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a), (c) is the II-II sectional view taken on the line of (a). It is an internal waveguide of 6th Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a), (c) is the II-II sectional view taken on the line (a). It is an internal waveguide of 7th Embodiment, (a) is a top view, (b) is the II sectional view taken on the line of (a), (c) is the II-II sectional view taken on the line (a). (A) is a top view of the internal waveguide of the modification of 1st Embodiment, (b) is the II sectional view taken on the line of (a), (c) is the internal waveguide of the modification of 2nd Embodiment. The top view and (d) are the II sectional view taken on the line of (c). (A) is a top view of the internal waveguide of the modification of 3rd Embodiment, (b) is II sectional view taken on the line of (a), (c) is the internal waveguide of the modification of 4th Embodiment. The top view and (d) are the II sectional view taken on the line of (c). (A) is a top view of the internal waveguide of the modification of 5th Embodiment, (b) is a top view of the internal waveguide of the modification of 6th Embodiment, (c) is the modification of 7th Embodiment. It is a top view of an internal waveguide. (A) is a plan view of a modified example in which the first and fifth embodiments are combined, (b) is a plan view of a modified example in which the first and sixth embodiments are combined, and (c) is a reflection film of the core part. It is a top view of the modification extended in the length direction of the internal waveguide along both sides. It is an internal waveguide of the optical module of background art, (a) is side surface sectional drawing, (b) is side surface sectional drawing which made the front end of a core part retreat.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Note that portions having the same configuration and operation as those of the background art are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 1 is a schematic side view of an optical module according to the present invention. In FIG. 1, an optical module includes a first substrate (mount substrate) 1 on a light emitting side, a first substrate (mount substrate) 3 on a light receiving side, and an optical fiber 2 that optically couples the first substrates 1 and 3. And.

  The first substrates 1 and 3 need to have rigidity in order to avoid the influence of heat during mounting and the influence of stress due to the use environment. In the case of optical transmission, since optical coupling efficiency from the light emitting element 12a to the light receiving element 12b is required, the optical elements (the light emitting element 12a and the light receiving element 12b) 12 can be mounted with high accuracy and the position in use. It is necessary to suppress fluctuations as much as possible. For this reason, a silicon (Si) substrate is employed as the first substrates 1 and 3 in this embodiment.

  In particular, in the case of a silicon substrate, it is possible to process a highly accurate etching groove on the surface by utilizing the crystal orientation of silicon [a highly accurate mirror portion 15 (described later) using this groove, and an internal waveguide 16 ( (To be described later). ]. In addition, the silicon substrate has good flatness.

  The first substrates 1 and 3 are respectively installed on the surface (upper surface) of a second substrate (interposer substrate) 6 having a larger size. Connectors 7 for electrically connecting to other circuit devices are respectively attached to the back surface (lower surface) of each second substrate 6.

  On the surface (upper surface) of the first substrate 1, a light emitting element 12a for converting an electric signal into an optical signal is flip-chip mounted with bumps 12c (see FIG. 13B) with the light emitting surface facing downward. An IC substrate (signal processing unit) 4a on which an IC circuit for transmitting an electrical signal to the light emitting element 12a is formed is mounted on the surface of the second substrate 6.

  In the present embodiment, a surface emitting laser (VCSEL (Vertical Cavity Surface Emitting Laser)) that is a semiconductor laser is employed as the light emitting element 12a. The light emitting element 12a may be an LED or the like.

  The IC substrate 4a is a driver IC that drives the VCSEL, and is disposed in the vicinity of the light emitting element 12a. The light emitting element 12a and the IC substrate 4a are connected to a metal circuit (patterning circuit by copper or gold sputtering) formed on the surface of the first substrate 1.

  On the surface of the first substrate 1, a substantially V-shaped first groove (waveguide forming groove) 1a as shown in FIG. 2C and a substantially V-shaped second groove 1b deeper than the first groove 1a. Are formed continuously in the front-rear direction.

  On the front end surface of the first groove 1a, an optical path changing mirror portion 15 for bending the optical path by 90 degrees is formed at a position directly below the light emitting element 12a. Referring to FIG. 2, the mirror unit 15 is configured by forming a reflective film (for example, an Au film) 15 a for improving the reflectance on the inclined surface 1 c that is the tip surface of the first groove 1 a of the substrate 1. Has been. In FIG. 2 and subsequent figures, the reflective film 15a is depicted as being relatively thick, but in actuality it is about several μm thick. In addition, the range required for the optical path conversion of the reflective film 15a is an extent shown by cross hatching in FIG. 2A, and the other ranges do not have an optical path conversion function.

  In the first groove 1a of the first substrate 1, an internal waveguide 16 that is optically coupled to the light emitting element 12a of the first substrate 1 is provided.

  Referring to FIG. 2, the internal waveguide 16 includes a core part 17 having a high refractive index through which light propagates and a clad part 18 having a refractive index lower than that. Both left and right sides of the core portion 17 are covered with a clad portion 18. The upper portion of the core portion 17 is substantially the same height as the surface of the first substrate 1, and the upper portion of the cladding portion 18 is slightly raised from the surface of the first substrate 1. The upper portion of the clad portion 18 is in close contact with the surface of the substrate 1 on both sides of the first groove 1a.

  Returning to FIG. 1, a light emitting element 12 a is mounted at a predetermined position on the surface of the first substrate 1 on which the internal waveguide 16 is provided. Between the light emitting element 12 a and the surface of the first substrate 1, Underfill is filled.

  On the other hand, the basic configuration of the first substrate 3 on the light receiving side is the same as that of the first substrate 1 on the light emitting side. However, a light receiving element 12b for converting an optical signal into an electrical signal is flip-chip mounted on the surface (upper surface) of the first substrate 3 on the light receiving side with the light receiving surface facing downward. In addition, on the surface of the second substrate 6, an IC substrate (signal processing unit) 4b on which an IC circuit for transmitting an electric signal to the light receiving element 12b is formed is mounted. Different from 1. As this light receiving element 12b, PD (Photo Diode) is adopted, and the IC substrate 4b is an element such as a TIA (Trans-impedance Amplifier) that performs current / voltage conversion.

  The first substrate 1 on the light emitting side, the first substrate 3 on the light receiving side, and the IC substrates 4a and 4b are respectively shielded by a shield case 8 attached to the surface of the second substrate 6, and the optical fiber 2 is shielded by the shield case 8 This through-hole 8a is made to penetrate.

  The optical fiber 2 is a fiber core part that can optically couple the core part 17 of the internal waveguide 16 of the first substrate 1 on the light emitting side and the core part 17 of the internal waveguide 16 of the first substrate 3 on the light receiving side. 21 inside. And it is a cord type comprised by the fiber clad part 22 surrounding the outer periphery of this fiber core part 21, and the coating | coated part 23 which coat | covers the outer periphery of this fiber clad part 22. FIG. The fiber core part 21, the fiber clad part 22, and the covering part 23 are circular.

  The optical fiber 2 passes through the through-hole 8a of the shield case 8, and the covering portion 23 is peeled off in the vicinity of the second groove 1b of the first substrate 1 so that the fiber cladding portion 22 is exposed.

  And the fiber clad part 22 of the optical fiber 2 is installed in the 2nd groove | channel 1b of the 1st board | substrate 1, and the fiber clad part 22 is positioned in the rising inclination part of the boundary part with the 1st groove | channel 1a. At this time, optical coupling is performed in a positioning state in which the optical axes of the core portion 17 of the internal waveguide 16 of the first substrate 1 and the fiber core portion 21 of the optical fiber 2 coincide.

  At the position of the surface of the first substrate 1, a presser block 24 is disposed above the fiber cladding portion 22 of the optical fiber 2, and the space between the presser block 24 and the second groove 1 b is filled with an adhesive. Has been.

  As described above, the front end side of the fiber clad portion 22 of the optical fiber 2 is bonded and fixed to the first substrate 1 together with the presser block 24 while being pressed against the second groove 1b by the presser block 24. become.

  2A and 2B show the internal waveguide 16 of the first embodiment, where FIG. 2A is a plan view, FIG. 2B is a cross-sectional view taken along line II of FIG. 2A, and FIG. 2C is a line II-II of FIG. It is sectional drawing.

  The cross-sectional shape of the first groove 1a of the substrate 1 is substantially V-shaped. The width of the upper portion of the clad portion 18 is set wider than the maximum width W of the mirror bottom 1e, but it may be set narrower.

  The front end 17 a of the core portion 17 is set at a position retracted from the mirror portion 15. Moreover, although the front end 18a of the clad part 18 is set at the position of the front end 1d of the substantially V-shaped groove portion of the first groove 1a, it is not always necessary to be at this position. These are the same even when the cross-sectional shape of the first groove 1a is substantially trapezoidal.

  The reflective film 15a formed on the inclined surface 1c of the substrate 1 is wider than the maximum width W of the mirror bottom 1e and is in close contact with the upper surface of the substrate 1 from the vicinity of the front end 15b. Then, it extends in the length direction of the internal waveguide 16 to at least the vicinity immediately before it does not overlap the front end 17 a of the core portion 17. If they do not overlap, they may coincide with the front end 17a of the core portion 17.

  If it is the structure of 1st Embodiment, the reflective film 15a is formed in the inclined surface 1c of the 1st groove | channel 1a, and the mirror part 15 is comprised. The reflection film 15a is formed with a formation range (see reference A) so as to extend from the upper surface of the substrate 1 in the length direction of the internal waveguide 16 to at least the vicinity of the front end 17a of the core portion 17. is there.

  Accordingly, since the reflective film 15a is not only in close contact with the inclined surface 1c but also in close contact with the upper surface of the substrate 1, the reflective film 15a is difficult to peel off from the substrate 1 and the yield of the optical module is increased. The rate will increase.

  In particular, when the cross-sectional shape of the first groove 1a is substantially V-shaped, the adhesiveness of the core portion 17 at the mirror bottom 1e where the UV light for curing treatment is difficult to reach becomes poor. Thus, by bringing the vicinity of the front end 17a of the core portion 17 into direct contact with the substrate 1 so as not to overlap the reflective film 15a, a better effect can be obtained for preventing the core portion 17 from peeling off. In addition, by setting the front end 17a of the core portion 17 to a position retracted from the mirror portion 15, the temperature rise of the core portion 17 is suppressed and peeling is less likely to occur.

  3A and 3B show the internal waveguide 16 according to the second embodiment. FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along the line II of FIG. The difference from the first embodiment is that the reflection film 15a has a formation range (see reference B) set so as to extend to the vicinity of the mirror bottom 1e.

  If it is the structure of 2nd Embodiment, the reflective film 15a will become more difficult to peel from the board | substrate 1, and the yield rate of an optical module will improve more. In addition, in combination with the fact that the reflective film 15a is difficult to peel from the substrate 1, the core part 17 overlaps the reflective film 15a (including the following embodiments) as a result. Becomes difficult to peel off from the substrate 1. As a result, the yield rate of the optical module is improved.

  4A and 4B show the internal waveguide 16 according to the third embodiment. FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along the line II of FIG. The difference from the first embodiment is that the reflective film 15a has a formation range (see reference C) set so as to extend to the vicinity of the front end 1d of the groove portion of the first groove 1a.

  If it is the structure of 3rd Embodiment, the reflective film 15a will become more difficult to peel from the board | substrate 1, and the yield rate of an optical module will improve more.

  5A and 5B show the internal waveguide 16 according to the fourth embodiment, where FIG. 5A is a plan view, FIG. 5B is a cross-sectional view taken along line II of FIG. 5A, and FIG. 5C is a line II-II of FIG. It is sectional drawing. The difference from the first embodiment is that the reflective film 15a has a formation range (see reference D) set so as to extend to the rear of the front end 1d of the groove portion of the first groove 1a.

  If it is the structure of 4th Embodiment, it will become difficult to peel the reflective film 15a from the board | substrate 1, and the yield rate of an optical module will improve more.

  In the first to fourth embodiments, the front end 17 a of the core portion 17 does not necessarily need to be set at a position retracted from the mirror portion 15. That is, as shown in FIGS. 9A and 9B corresponding to the first embodiment, the upper portion of the core portion 17 is slightly raised from the surface of the first substrate 1, and the front end 17 a is the mirror portion 15. It is located near the top of Further, the upper portion of the clad portion 18 is slightly raised from the upper portion of the core portion 17, and the front end 18 a extends from the upper end of the mirror portion 15 to be in close contact with the surface of the substrate 1. It can also be configured in this way.

  9C and 9D corresponding to the second embodiment, FIGS. 10A and 10B corresponding to the third embodiment, and FIGS. 10C and 10D corresponding to the fourth embodiment. It is the same.

  6A and 6B show the internal waveguide 16 according to the fifth embodiment, where FIG. 6A is a plan view, FIG. 6B is a cross-sectional view taken along line II in FIG. 6A, and FIG. It is sectional drawing. The difference from the fourth embodiment is that the reflective film 15a has a formation range (see symbol E) that is narrower than the width of the core portion 17 of the internal waveguide 16.

  With the configuration of the fifth embodiment, coupled with the fact that the reflective film 15a is difficult to peel from the substrate 1, both side portions of the core part 17 do not overlap with the reflective film 15a. Becomes difficult to peel off from the substrate 1. As a result, the yield rate of the optical module is improved.

  7A and 7B show the internal waveguide 16 of the sixth embodiment, where FIG. 7A is a plan view, FIG. 7B is a cross-sectional view taken along line II of FIG. 7A, and FIG. 7C is a line II-II of FIG. It is sectional drawing. The difference from the fourth embodiment is that the reflection film 15a has a formation range (see reference F) so as to have a width near the upper end 1f of the first groove 1a.

  With the configuration of the sixth embodiment, coupled with the fact that the reflective film 15a is less likely to peel from the substrate 1, the clad portion 18 and the core portion 17 overlap the reflective film 15a as a result. The part 18 and the core part 17 are also difficult to peel from the substrate 1. As a result, the yield rate of the optical module is improved.

  8A and 8B show the internal waveguide 16 of the seventh embodiment, where FIG. 8A is a plan view, FIG. 8B is a cross-sectional view taken along the line II of FIG. 8A, and FIG. 8C is the II-II line of FIG. It is sectional drawing. The seventh embodiment is basically the same configuration as the fourth embodiment of FIG. 5, and specifically, the reflection film 15a is formed to be wider than the width of the upper end 1f of the first groove 1a. This is a point where a range (see symbol G) is set.

  If it is the structure of 7th Embodiment, the reflective film 15a will become more difficult to peel from the board | substrate 1, and the yield rate of an optical module will improve more.

  In the fifth to seventh embodiments, the front end 17 a of the core portion 17 does not necessarily need to be set at a position retracted from the mirror portion 15. That is, as shown in FIG. 11A corresponding to the fifth embodiment, the upper portion of the core portion 17 is slightly raised from the surface of the first substrate 1, and the front end 17 a is near the upper end of the mirror portion 15. Is located. Further, the upper portion of the clad portion 18 is slightly raised from the upper portion of the core portion 17, and the front end 18 a extends from the upper end of the mirror portion 15 to be in close contact with the surface of the substrate 1. It can also be configured in this way.

  The same applies to FIG. 11 (b) corresponding to the sixth embodiment and FIG. 11 (c) corresponding to the seventh embodiment.

  In the first to fourth embodiments (including the modified examples of FIGS. 9 and 10), the reflective film 15 a extends in the length direction of the internal waveguide 16, so that the adhesion with the substrate 1 is improved. To do.

  In the fifth to seventh embodiments (including the modification of FIG. 11), the reflective film 15 a extends in the width direction of the internal waveguide 16, thereby improving the adhesion with the substrate 1. .

  From these things, it is also possible to combine 1st-4th embodiment and 5th-7th embodiment suitably. For example, FIG. 12A is a modified example in which the first embodiment and the fifth embodiment are combined, and FIG. 12B is a modified example in which the first embodiment and the sixth embodiment are combined. In addition, as shown in FIG. 12C, in the first embodiment, the reflective film 15 a can be extended in the length direction of the internal waveguide 16 along both sides of the core portion 17.

1 First substrate (substrate)
1a 1st groove (groove for waveguide formation)
1c Inclined surface (tip surface)
1d Front end 1e of groove portion Mirror bottom 1f Upper end 12a Light emitting element 12b Light receiving element 15 Mirror part 15a Reflective film 15b Front end 16 Internal waveguide 17 Core part 17a Front end 18 Clad part 18a Front end

Claims (8)

An internal waveguide provided in a waveguide forming groove formed on the surface of the substrate, an optical path converting mirror formed on the front end surface of the groove, and the surface of the substrate so as to face the mirror And an optical module that includes at least an optical element that emits an optical signal to the core portion of the internal waveguide via the mirror portion or receives an optical signal from the core portion of the internal waveguide via the mirror portion. In
The mirror portion is configured by forming a reflective film on an inclined surface that is a tip surface of the waveguide forming groove, and the reflective film extends from the upper surface of the substrate in the length direction of the internal waveguide. An optical module characterized by being present.   The front end of the core part is set at a position retracted from the mirror part, and the reflective film extends to a position not overlapping the front end of the core part. Optical module.   The optical module according to claim 1, wherein the reflective film extends to a vicinity of a mirror bottom of the waveguide forming groove.   The optical module according to claim 1, wherein the reflective film extends to a vicinity of a front end of a groove portion of the waveguide forming groove.   3. The optical module according to claim 1, wherein the reflection film extends to a rear side from a front end of a groove portion of the waveguide forming groove.   The optical module according to claim 1, wherein the reflective film is set to be narrower than a width of a core portion of the internal waveguide.   The optical module according to claim 1, wherein the reflective film is set to have a width in the vicinity of an upper end of the waveguide forming groove.   The optical module according to claim 1, wherein the reflection film is set wider than an upper end width of the waveguide forming groove.

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