JP5879541B2 - Optical module - Google Patents

Description

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

  2. Description of the Related Art Conventionally, an optical module includes an internal waveguide provided in a groove formed on the surface of a substrate, and an optical path conversion mirror part formed at the tip of the groove. Also, 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 light from the core part of the internal waveguide through the mirror part. An optical element for receiving a signal is provided. Furthermore, an external waveguide having a core portion optically coupled to the core portion of the internal waveguide is provided. (See Patent Document 1).

  In such an optical module, it is necessary to use a plurality of optical modules in order to increase bidirectional transmission and transmission capacity. Therefore, it is desired to realize an optical module that is small and low-profile and capable of bidirectional or multi-channel transmission.

  In order to realize such an optical module, it is conceivable to mount a plurality of optical elements close to the surface of the substrate, and an internal waveguide and a mirror are arranged in accordance with the interval between the plurality of optical elements. It is necessary to form the portions at a narrow pitch.

  A plurality of optical transmission lines having different lengths from the end face of the substrate are formed on the substrate, and optical elements are arranged close to the end of each optical transmission line, and each optical element emits light. There has been proposed an optical module that is one of an element and a light receiving element (see Patent Document 2). In this patent document 2, no crosstalk noise is dealt with, and when an optical fiber is used, it is necessary to process the optical fiber length with a different length, which makes it very difficult to manufacture.

JP 2009-260227 A JP 2003-294964 A

  However, when a plurality of optical elements are brought close to each other and the internal waveguide and the mirror part are formed at a narrow pitch, leakage light from the optical element and scattered light from the mirror part and the internal waveguide are adjacent to each other. Crosstalk noise is generated by entering the mirror part and the internal waveguide. Since such crosstalk noise causes a transmission error, there is a demand to reduce it as much as possible.

  The present invention has been made to meet the above-mentioned demand, and makes it difficult for light leaked from a plurality of optical elements on the same substrate to affect adjacent optical elements and the like, thereby greatly reducing crosstalk noise. An object of the present invention is to provide an optical module configured as described above.

In order to solve the above-described problems, the present invention provides an internal waveguide provided in a first groove formed on the surface of a substrate, and an optical path conversion mirror formed at the tip of the first groove. The optical signal is mounted on the surface of the substrate so as to face the mirror part, and emits an optical signal to the core part of the internal waveguide through the mirror part, or the optical signal from the core part of the internal waveguide through the mirror part. And an external waveguide having a core portion optically coupled to the core portion of the internal waveguide, the plurality of first grooves of the substrate being substantially parallel in an independent state. The optical elements are formed so that adjacent first grooves have different lengths from the end face of the substrate, and are opposed to the mirror portions respectively formed at the tips of the first grooves having different lengths. There are respectively mounted on the surface of the substrate, the surface of the substrate A second groove connected to the first groove of the internal waveguide is formed, and the external waveguide is fitted and fixed in the second groove, so that the optical axes of the internal waveguide and the external waveguide coincide with each other. it is is to provide an optical module according to claim.

  The plurality of optical elements include both a light emitting element and a light receiving element, and the light emitting element faces the mirror part of the internal waveguide having a shorter length than the light receiving element. It can be set as the structure mounted on the surface.

  It can be set as the structure by which the partition wall part is formed between the adjacent 2nd groove | channels so that the partition wall part between the said adjacent 1st groove | channels may not be interrupted.

  The external waveguide may be a multi-channel optical fiber.

  The external waveguide may be a multi-channel flexible waveguide.

  A convex layer of the same material as that of the clad portion of the internal waveguide may be formed on the surface of the substrate between the optical elements.

  The convex layer may be configured to be an absorber that absorbs light.

  According to the present invention, the optical elements are mounted on the surface of the substrate so that the lengths of the first grooves adjacent to each other are different from each other and face the mirror part at the tip of the first groove having a different length. Thus, a large distance can be separated between adjacent optical elements that are staggered in the length direction.

  Therefore, leakage light from the optical element and reflected / scattered light from the mirror part and internal waveguide are less likely to enter the mirror part and internal waveguide of the adjacent optical element, so that crosstalk noise is less likely to occur. Further, since the plurality of internal waveguides are provided in the first grooves formed in an independent state and substantially in parallel, the internal waveguides do not interfere with each other at the partition wall portions of the adjacent first grooves.

In this way, a plurality of optical elements are mounted close to each other in the width direction on the substrate, and the internal waveguide and the mirror portion are formed at a narrow pitch in accordance with the interval between the optical elements. Bi-directional or multi-channel transmission is possible. In addition, it is possible to greatly reduce crosstalk noise by combining a large distance between adjacent optical elements and preventing interference between adjacent internal waveguides.
Further, in the present invention, a second groove that is continuous with the first groove of the internal waveguide is formed on the surface of the substrate, and the external waveguide is fitted and fixed in the second groove so that the internal waveguide and the external waveguide are fixed. The optical axes of the waveguides are set to coincide. According to this, by forming the first groove and the second groove for fitting the external waveguide on the substrate on which the optical element is mounted, the optical assembly of the internal waveguide and the external waveguide becomes easy, A highly accurate optical module can be manufactured at low cost.

1 is a schematic side view of an optical module according to the present invention. It is the 1st board | substrate of the optical module of the light emission side of FIG. 1, (a) is side surface sectional drawing, (b) is II sectional view taken on the line of (a), (c) is II-II line of (a). It is sectional drawing. 2A is a perspective view of the first substrate of FIG. 2, and FIG. 3B is a perspective view in which an internal waveguide is formed. FIG. 3A is a perspective view in which a light emitting element is mounted, and FIG. 3B is a perspective view in which an optical fiber is inserted. (A) is the perspective view which fixed the holding | suppressing block to the 1st board | substrate, (b) is a perspective view of an optical fiber. (A) is a top view of the board | substrate which concerns on embodiment, (b) is an enlarged plan view of a 1st groove | channel and an internal waveguide. (A) is the III-III line expanded sectional view of Fig.6 (a), (b) is the IV-IV line expanded sectional view of Fig.6 (a). It is a top view of the board | substrate which formed the partition wall part between 2nd grooves so that the partition wall part between 1st grooves might not be interrupted. It is a modification, (a) is a top view of a board | substrate, (b) is the VV line expanded sectional view of (a).

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic side view of an optical module according to the present invention. 2 is a first substrate 1 of the light-emitting side optical module of FIG. 1, (a) is a side sectional view, (b) is a sectional view taken along line II of (a), and (c) is a sectional view of (a). It is II-II sectional view taken on the line. 3A and 3B show the first substrate 1. FIG. 3A is a perspective view, and FIG. 3B is a perspective view in which an internal waveguide 16 is formed. 4A and 4B show the first substrate 1, in which FIG. 4A is a perspective view in which the light emitting element 12a is mounted, and FIG. 4B is a perspective view in which the optical fiber 2 is inserted. FIG. 5A is a perspective view in which the holding block 24 is fixed, and FIG. 5B is a perspective view of the optical fiber 2.

  Here, FIGS. 1 to 5 are single-channel optical modules in which one internal waveguide 16 is formed in one first groove 1a of the first substrates 1 and 3, but FIGS. First, the outline of the optical module will be described with reference to FIG. 5, and then the multi-channel optical module according to the present invention will be described in detail with reference to FIGS.

  In FIG. 1, the optical module includes a first substrate (mount substrate) 1 on the light emitting side, a first (mount) substrate 3 on the light receiving side, and an optical fiber 2 that optically couples the first substrates 1 and 3. It has.

  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. Further, in the case of optical transmission, since optical coupling efficiency from the light emitting element 12a to the light receiving element 12b is required, mounting of the light emitting element 12a and the light receiving element 12b with high accuracy and minimizing positional fluctuation during use are minimized. There is a need. 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 that converts an electrical signal into an optical signal is flip-chip mounted with bumps 12c (see FIG. 2) 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, as shown in FIG. 3 (a), a substantially trapezoidal first groove (waveguide forming groove) 1a and a substantially V-shaped second deeper than the first groove 1a. The groove 1b is formed continuously in the front-rear direction.

  At the tip of the first groove 1a, an optical path changing mirror 15 for bending the optical path by 90 degrees is formed at a position directly below the light emitting element 12a.

  As shown in FIG. 3B, an internal waveguide 16 that is optically coupled to the light emitting element 12a of the first substrate 1 is provided in the first groove 1a of the first substrate 1. The internal waveguide 16 extends from the mirror portion 15 in the direction of the second groove 1b and is flush with the rear end portion 1d of the first groove 1a.

  The internal waveguide 16 includes a core portion 17 having a substantially square cross section with a high refractive index through which light propagates, and a cladding portion 18 having a refractive index lower than that. As shown in FIG. 2C, the left and right surfaces of the core portion 17 are covered with the cladding portion 18.

  As shown in FIG. 4A, a light emitting element 12a is mounted at a predetermined position on the surface of the first substrate 1 on which the internal waveguide 16 is provided, and the space between the light emitting element 12a and the core portion 17 is mounted. As shown in FIG. 2A, an optical transparent resin (underfill material) 13 is filled.

  Returning to FIG. 1, the first substrate 3 on the light receiving side will be described. The basic structure 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, on the surface (upper surface) of the first substrate 3 on the light receiving side, a light receiving element 12b for converting an optical signal into an electric signal is flip-chip mounted with bumps 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.

  Next, the optical fiber (external waveguide) 2 will be described. As shown in FIGS. 1 and 5, the optical fiber 2 includes a core portion 17 of the internal waveguide 16 of the first substrate 1 on the light emitting side, and a core portion 17 of the internal waveguide 16 of the first substrate 3 on the light receiving side. Are internally provided with a fiber core portion 21 that can be optically coupled. 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.

  As shown in FIG. 1, the optical fiber 2 penetrates 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 clad portion 22 is exposed. ing.

  Then, as shown in FIGS. 2A, 2C, and 4B, the fiber cladding portion 22 of the optical fiber 2 is installed in the second groove 1b of the first substrate 1, and the boundary with the first groove 1a. The fiber cladding portion 22 is positioned at the rising slope of the portion. 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, as shown in FIGS. 2A and 5, a holding block 24 is disposed on the upper portion of the fiber cladding portion 22 of the optical fiber 2, and the holding block 24 and the second groove 1 b are arranged. The space between is filled with an adhesive 14.

  As described above, the distal 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 pressing block 24 with the adhesive 14 while being pressed against the second groove 1 b by the pressing block 24. It becomes like this.

  6 and 7 show a multi-channel optical module according to the present invention. 6A is a plan view of the substrate 1, and FIG. 6B is an enlarged plan view of the first grooves 1a-1 and 1a-2 and the internal waveguides 16-1 and 16-2. In FIG. 6B, the clad portion 18 is hatched for easy understanding of the range of the clad portion 18.

  Fig.7 (a) is the III-III line expanded sectional view of Fig.6 (a), The same (b) is the IV-IV line expanded sectional view of Fig.6 (a).

  On the surface of the substrate 1, a plurality of (in this example, two) substantially trapezoidal first grooves 1a-1 and 1a-2 are in an independent state, that is, adjacent to the first grooves 1a-1 and 1a-2. It is formed substantially in parallel with the space partitioned by the partition wall portion 1e.

  The adjacent first grooves 1a-1 and 1a-2 have different lengths L1 and L2 from the end face of the first substrate 1 (in this example, the rear end 1d of the first groove 1a). In the first grooves 1a-1 and 1a-2, internal waveguides 16-1 and 16-2 are respectively provided as described above.

  The optical elements (the light emitting element 12a and the light receiving element 12b) are placed on the surface of the first substrate 1 so as to face the mirror portions 15 formed at the tip portions of the first grooves 1a-1 and 1a-2 having different lengths. Has been implemented. In this example, the mirror part 15 of the long internal waveguide 16-1 having the length L1 is opposed to the light receiving element 12b, and the mirror part 15 of the short internal waveguide 16-2 having the length L2 is opposed to the light emitting element 12a. Yes. Only the light emitting element 12a can be opposed to the mirror portion 15 of each of the internal waveguides 16-1 and 16-2, or only the light receiving element 12b can be opposed. Further, the number of the first grooves 1a-1 and 1a-2 is not limited to two, and may be three or more. In this case, it is only necessary that the lengths of the three adjacent first grooves are different, and the lengths of the first and third grooves may be equal. Similarly, in the case of four or more, the first grooves that are not adjacent to each other may have the same length.

  On the surface of the first substrate 1, two substantially trapezoidal second grooves 1 b-1 and 1 b-2 respectively connected to the two first grooves 1 a-1 and 1 a-2 are formed. Between the adjacent second grooves 1b-1 and 1b-2, in the inclined portion 1h between the bottom of the second grooves 1b-1 and 1b-2 and the bottom of the first grooves 1a-1 and 1a-2, It is partitioned off by a partition wall portion 1f in a state of being disconnected from the partition wall portion 1e between the 1 grooves 1a-1 and 1a-2.

  As shown in FIG. 6A, the optical fiber (external waveguide) 2 includes two parallel fiber core portions 21 that can be optically coupled to the core portions 17 of the internal waveguides 16-1 and 16-2. (Multiple channels), and the outer periphery of each fiber core portion 21 is surrounded by a fiber clad portion 22. Instead of the optical fiber 2, a multi-channel flexible waveguide (external waveguide) may be used.

  And each fiber clad part 22 and 22 is each fitted and fixed to 2nd groove | channel 1b-1 and 1b-2, respectively, Each core part 17 of internal waveguide 16-1 and 16-2, and each fiber of the optical fiber 2 The optical axis of the core part 21 is set to coincide.

  As shown in FIG. 8, by forming the second grooves 1b-1 and 1b-2 in an independent state so as not to be interrupted by the partition wall portion 1e between the adjacent first grooves 1a-1 and 1a-2, A partition wall portion 1g between the adjacent second grooves 1b-1 and 1b-2 can also be formed.

  If the optical module is configured as described above, the adjacent first grooves 1a-1, 1a-2 of the first substrate 1 have different lengths L1, L2. Then, the optical elements (the light emitting element 12a and the light receiving element 12b) are arranged on the first substrate 1 so as to face the mirror portions 15 at the tip ends of the first grooves 1a-1 and 1a-2 having different lengths L1 and L2, respectively. Mount on the surface. Accordingly, a large distance (space) S (see FIG. 6A) can be separated between adjacent optical elements (light emitting element 12a and light receiving element 12b) that are staggered in the length direction.

  Therefore, the optical element, in particular, the light leaked from the light emitting element 12a and the reflected scattered light from the mirror part 15 and the internal waveguide 16-2 are adjacent to each other, particularly the mirror part 15 and the internal waveguide 16- of the light receiving element 12b. 1 is difficult to get into. This makes it difficult for crosstalk noise to occur.

  Moreover, since the internal waveguides 16-1 and 16-2 are provided in the first grooves 1a-1 and 1a-2 in which a plurality (two in this example) are formed in an independent state and substantially parallel, The internal waveguides 16-1 and 16-2 do not interfere with each other at the partition wall portion 1e of the adjacent first grooves 1a-1 and 1a-2.

  As described above, a plurality of optical elements (light emitting element 12a and light receiving element 12b) are mounted on the first substrate 1 so as to be close to each other in the width direction, and according to the interval between the optical elements (light emitting element 12a and light receiving element 12b), The internal waveguides 16-1 and 16-2 and the mirror portion 15 are formed at a narrow pitch. Thereby, it is small and low-profile, and bi-directional or multi-channel transmission is possible.

  In addition, a large distance S is separated between adjacent optical elements (light emitting element 12a and light receiving element 12b), and interference between adjacent internal waveguides 16-1 and 16-2 is prevented. Thus, crosstalk noise can be greatly reduced.

  When the plurality of optical elements include both the light emitting element 12a and the light receiving element 12b, the light emitting element 12a includes the mirror section 15 of the internal waveguide 16-2 having a length L2 shorter than the light receiving element 12b. It is mounted on the surface of the first substrate 1 so as to face each other.

  As described above, the light emitting element 12a is arranged on the end surface of the first substrate 1 (in this example, the rear end 1d of the first groove 1a) with respect to the light receiving element 12b. Thereby, the reflected and scattered light of the mirror part 15 on the light emitting element 12a side hardly affects the light receiving element 12b side due to the orientation of the mirror part 15 on the light emitting element 12a side. Therefore, even if both the light emitting element 12a and the light receiving element 12b are mounted on the first substrate 1, the crosstalk noise can be greatly reduced.

Further, second grooves 1b-1 and 1b-2 connected to the first grooves 1a-1 and 1a-2 of the internal waveguides 16-1 and 16-2 are formed on the surface of the first substrate 1. Then, by inserting and fixing the fiber clad portions 22 of the optical fiber 2 in the second grooves 1b-1 and 1b-2, the core portions 17 of the internal waveguides 16-1 and 16-2 and the optical fiber 2 are fixed. The optical axes of the respective fiber core portions 21 are aligned with each other. Therefore, by forming the first grooves 1a-1, 1a-2 and the second grooves 1b-1, 1b-2 into which the fiber clad portions 22 of the optical fiber 2 are fitted in the first substrate 1, Optical assembly of the internal waveguides 16-1 and 16-2 and the optical fiber 2 is facilitated, and a highly accurate optical module can be manufactured at low cost.

Further, in FIG. 8 , the adjacent second grooves 1 b-1 and 1 b-2 are arranged on the surface of the substrate 1 so that the partition wall portion 1 e between the adjacent first grooves 1 a-1 and 1 a-2 is not interrupted. A partition wall portion 1g is formed therebetween. According to this, since the leaked light does not interfere with the adjacent waveguide at the optical coupling portion between the internal waveguides 16-1 and 16-2 and the optical fiber 2, the crosstalk noise can be further reduced. Become.

  Furthermore, if the external waveguide is a multi-channel optical fiber 2, optical assembly is facilitated by adjusting the pitch of the internal waveguides 16-1 and 16-2 to the pitch of the ready-made optical fiber 2. An optical module can be manufactured at low cost.

  If the external waveguide is a multi-channel flexible waveguide, the optical assembly is facilitated by matching the pitch of the internal waveguides 16-1 and 16-2 with the pitch of the ready-made flexible waveguide, An optical module can be manufactured at low cost.

  FIG. 9 is a modified example, (a) is a plan view of the substrate 1, and (b) is an enlarged cross-sectional view taken along the line VV of (a). A convex layer 26 of the same material as that of the clad portion 18 of the internal waveguide 16 is formed on the surface of the first substrate 1 between the light emitting element 12a and the light receiving element 12b.

  According to this, the light emitting element 12a and the light receiving element 12b are formed by forming the convex layer 26 of the same material as the clad portion 18 having a high refractive index on the surface of the first substrate 1 between the light emitting element 12a and the light receiving element 12b. Since the leaked light can be trapped, the crosstalk noise can be further reduced. The convex layer 26 can also be used as a flow stop for the underfill material, which is the optical transparent resin 13 filled between the light emitting element 12 a, the light receiving element 12 b, and the surface of the first substrate 1. The material of the convex layer 26 is not limited to the same material as that of the clad portion 18, but if it is the same material, it can be simultaneously formed in the formation process of the clad portion 18.

  Further, if the absorber that absorbs light is used as the material of the convex layer 26 instead of the same material as that of the clad portion 18, the leakage light between the light emitting element 12a and the light receiving element 12b can be absorbed. It becomes possible to reduce more. Here, as the absorber, there is a colored resin, for example, an opaque acrylic resin or epoxy resin.

  As described above, the optical module according to the present invention includes the internal waveguide provided in the first groove formed on the surface of the substrate, and the optical path conversion mirror portion formed at the tip of the first groove. And is mounted on the surface of the substrate so as to face the mirror part, and emits an optical signal to the core part of the internal waveguide through the mirror part, or light from the core part of the internal waveguide through the mirror part. In an optical module comprising an optical element for receiving a signal and an external waveguide having a core portion optically coupled to the core portion of the internal waveguide, a plurality of first grooves of the substrate are substantially parallel in an independent state. The first grooves adjacent to each other have different lengths from the end face of the substrate, and are opposed to the mirror portions respectively formed at the tips of the first grooves having different lengths. The element is mounted on the surface of the board. Is shall.

  According to this, by mounting the optical elements on the surface of the substrate so that the lengths of the adjacent first grooves are different from each other and face the mirror part at the tip of the first groove having different lengths, respectively. A large distance can be provided between adjacent optical elements that are staggered in the length direction.

  Therefore, leakage light from the optical element and reflected / scattered light from the mirror part and internal waveguide are less likely to enter the mirror part and internal waveguide of the adjacent optical element, so that crosstalk noise is less likely to occur. Further, since the plurality of internal waveguides are provided in the first grooves formed in an independent state and substantially in parallel, the internal waveguides do not interfere with each other at the partition wall portions of the adjacent first grooves.

In this way, a plurality of optical elements are mounted close to each other in the width direction on the substrate, and the internal waveguide and the mirror portion are formed at a narrow pitch in accordance with the interval between the optical elements. Bi-directional or multi-channel transmission is possible. In addition, it is possible to greatly reduce crosstalk noise by combining a large distance between adjacent optical elements and preventing interference between adjacent internal waveguides.
Further, in the present invention, a second groove that is continuous with the first groove of the internal waveguide is formed on the surface of the substrate, and the external waveguide is fitted and fixed in the second groove so that the internal waveguide and the external waveguide are fixed. The optical axes of the waveguides are set to coincide. According to this, by forming the first groove and the second groove for fitting the external waveguide on the substrate on which the optical element is mounted, the optical assembly of the internal waveguide and the external waveguide becomes easy, A highly accurate optical module can be manufactured at low cost.

  The plurality of optical elements include both a light emitting element and a light receiving element, and the light emitting element faces the mirror part of the internal waveguide having a shorter length than the light receiving element. It can be set as the structure mounted on the surface.

  According to this, by arranging the light emitting element closer to the end face side of the substrate than the light receiving element, the reflected and scattered light of the mirror part on the light emitting element side is directed to the light receiving element side in relation to the orientation of the mirror part on the light emitting element side. It becomes difficult to influence. Therefore, even if both the light emitting element and the light receiving element are mounted on the substrate, the crosstalk noise can be greatly reduced.

  It can be set as the structure by which the partition wall part is formed between the adjacent 2nd groove | channels so that the partition wall part between the said adjacent 1st groove | channels may not be interrupted.

  According to this, since the leaked light does not interfere with the adjacent waveguide at the optical coupling portion between the internal waveguide and the external waveguide, crosstalk noise can be further reduced.

  The external waveguide may be a multi-channel optical fiber.

  According to this, by matching the pitch of the internal waveguide with the pitch of the off-the-shelf optical fiber, optical assembly becomes easy, and an optical module can be manufactured at low cost.

  The external waveguide may be a multi-channel flexible waveguide.

  According to this, by matching the pitch of the internal waveguide with the pitch of the ready-made flexible waveguide, optical assembly becomes easy, and an optical module can be manufactured at low cost.

  A convex layer of the same material as that of the clad portion of the internal waveguide may be formed on the surface of the substrate between the optical elements.

  According to this, by forming a convex layer of the same material as the clad portion having a high refractive index on the surface of the substrate between the optical elements, it is possible to trap light leaking between the optical elements, thereby further reducing crosstalk noise. become able to. The convex layer can also be used as a flow stopper for the underfill material filled between the optical element and the surface of the substrate.

  The convex layer may be configured to be an absorber that absorbs light.

  According to this, since the absorber is formed on the surface of the substrate between the optical elements, the leakage light between the optical elements can be absorbed, so that the crosstalk noise can be further reduced.

DESCRIPTION OF SYMBOLS 1 Board | substrate 1a-1, 1a-2 1st groove | channel 1b-1, 1b-2 2nd groove | channel 1e, 1f, 1g Partition wall part 2 Optical fiber (external waveguide)
12a Light emitting element (optical element)
12b Light receiving element (optical element)
13 Optical transparent resin 15 Mirror parts 16-1, 16-2 Internal waveguide 17 Core part 18 Clad part 21 Fiber core part 22 Fiber clad part 26 Convex layer (absorber)
L1, L2 length

Claims (7)

An internal waveguide provided in the first groove formed on the surface of the substrate, an optical path converting mirror formed at the tip of the first groove, and the surface of the substrate facing the mirror And an optical element that emits an optical signal to the core part of the internal waveguide via the mirror part or receives an optical signal from the core part of the internal waveguide via the mirror part, and the core of the internal waveguide In an optical module comprising an external waveguide having a core portion optically coupled to the portion,
A plurality of first grooves of the substrate are formed substantially in parallel in an independent state, and the adjacent first grooves have different lengths from the end surface of the substrate, and are formed at the tips of the first grooves having different lengths. The optical elements are respectively mounted on the surface of the substrate so as to face the formed mirror parts ,
A second groove connected to the first groove of the internal waveguide is formed on the surface of the substrate, and the optical axis of the internal waveguide and the external waveguide is adjusted by fitting and fixing the external waveguide in the second groove. Set to match,
An optical module characterized by that.   The plurality of optical elements include both a light emitting element and a light receiving element, and the light emitting element faces the mirror part of the internal waveguide having a shorter length than the light receiving element. The optical module according to claim 1, wherein the optical module is mounted on a surface. The optical module according to claim 1 or 2, characterized in that the partition wall portion is formed between the partition so uninterrupted wall portion, adjacent the second groove between the first groove the adjacent. The external waveguide, the optical module according to any one of claims 1 to 3, characterized in that an optical fiber of a plurality of channels. The external waveguide, the optical module according to any one of claims 1 to 3, characterized in that a flexible waveguide for a plurality of channels. Wherein the surface of the substrate between the respective optical elements, the light according to any one of claims 1 to 5, characterized in that the convex-type layer of the cladding portion of the same material of the internal waveguide is formed module. The optical module according to claim 6 , wherein the convex layer is an absorber that absorbs light.

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