JP2009008767A - Optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical module having high adhesion strength between a mount substrate and an external waveguide substrate. <P>SOLUTION: The module includes mount substrates in a light emitting side and in a light receiving side, and an external waveguide substrate 2 provided with a connecting piece 5. The mount substrate has an adhesive filling section to be filled with an adhesive in a part of a portion where the connecting piece 5 overlaps. The connecting piece 5 of the external waveguide substrate 2 has an adhesion section 51 having an air vent hole 55 in a portion facing the adhesion filling section so as to release air bubbles generated in an adhesive filled in the adhesive filling section through the air vent hole 55. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical module that transmits or receives an optical signal.

As an optical transmission module for transmitting or receiving optical signals, for example, a polymer optical waveguide film (external waveguide substrate) on which an optical waveguide is formed, and a submount (mount substrate) holding optical elements (light emitting elements, light receiving elements) There is known an arrangement in which the light emitted from the optical element is coupled to the incident end face of the optical waveguide by being disposed on the upper side of the optical element and bonded with an adhesive (see Patent Document 1).
JP 2006-243467 A

  However, if the polymer optical waveguide film is disposed on the upper surface of the submount and simply adhered as described above, the polymer optical waveguide film may be detached from the submount when the polymer optical waveguide film is bent in use. .

  In addition, the position of the optical waveguide may be shifted with respect to the outer shape of the polymer optical waveguide film. In this case, the position of the optical waveguide is not changed even if the polymer optical waveguide film is disposed at a predetermined position of the submount. As a result, the optical axis shift occurs and the optical coupling efficiency is likely to decrease.

  In addition, since an adhesive is inserted between the polymer optical waveguide film provided with the optical waveguide and the submount holding the optical element, the distance between the optical waveguide and the optical element is increased, and the optical coupling efficiency may be reduced. Is expensive.

  An object of the present invention is to provide an optical module capable of securely bonding an external waveguide substrate and a mount substrate.

  It is another object of the present invention to provide an optical module that is unlikely to be displaced due to the inflow of an adhesive and that is less likely to cause optical axis misalignment.

  In order to solve the above-described problems, the present invention provides a light that connects a mount substrate provided with an optical waveguide and an external waveguide substrate provided with an external waveguide that is optically coupled to the waveguide of the mount substrate. A module, wherein when the waveguide and the external waveguide are optically coupled to any one of the mount substrate and the external waveguide substrate, the mount substrate and the external waveguide substrate; A connecting piece that is superimposed on a part of the other is provided, and the connecting piece includes an adhesive portion that is adhered to the other external waveguide substrate or the mount substrate, and the adhesive portion includes at least one adhesive portion. An optical module comprising an air vent hole is provided.

  The other external waveguide substrate or mount substrate is provided with an adhesive filling recess on the overlapping surface that is overlapped with the bonding portion of the connecting piece, and the adhesive filling recess is formed on the overlapping surface. It is formed larger than the air vent hole of the bonded portion of the overlapping connecting piece, and the inside of the adhesive filling recess and the outer surface side of the connecting piece communicate with each other through the air vent hole. An adhesive layer is provided by adhering the adhesive portion to the other external waveguide substrate or mount substrate, and the adhesive layer passes through the air vent hole of the connecting piece from the inside of the concave portion for filling the adhesive. It is preferable that an adhesive is disposed on at least a part of the peripheral portion of the air vent hole on the outer surface side of the connecting piece.

  The other external waveguide substrate or the mount substrate is provided with an adhesive filling concave portion on an overlapping surface to be overlaid on the adhesive portion of the coupling piece, and the adhesive filling concave portion has at least one marker. It is preferable that the marker is disposed at a predetermined position visible from the air vent hole of the connecting piece in a state where the waveguide and the external waveguide are optically coupled.

  The other external waveguide substrate or the mount substrate is provided with an adhesive filling recess on an overlapping surface to be overlapped with the bonding portion of the connecting piece, and the adhesive filling recess has at least one protrusion. The protrusion is in contact with a part of the inner peripheral wall of the air vent hole of the connecting piece in a state where the waveguide and the external waveguide are optically coupled, and the protrusion of the inner peripheral wall of the air vent hole It is preferable that a gap is formed between other portions.

  According to invention of Claim 1, when the adhesive agent is arrange | positioned in the adhesion part of a connection piece, the bubble by the air produced | generated in the adhesive agent can be driven out from an air vent hole. Thereby, generation | occurrence | production of a non-bonding part can be suppressed with a bubble, and it can adhere | attach reliably.

  According to invention of Claim 2, an adhesive bond layer can be formed in a rivet shape through an air vent hole, and adhesive strength can be improved.

  According to the invention of claim 3, the state where the waveguide and the external waveguide are optically coupled by visually confirming from the air vent hole of the connecting piece whether or not the marker is in a predetermined position set in advance. Whether the waveguide and the external waveguide are misaligned can be prevented. Further, when the marker is deviated from a predetermined position set in advance, it may be adjusted to the predetermined position, whereby the waveguide and the external waveguide can be optically coupled to each other. The positioning with the external waveguide can be easily performed, and the both can be bonded in a state where the both are reliably positioned.

  According to invention of Claim 4, protrusion can be utilized as a marker and the same effect as the above-mentioned case can be acquired. Further, since the protrusion is configured to abut on a part of the inner peripheral wall of the air vent hole of the connecting piece, the adhesive strength can be further increased. In addition, air bubbles formed in the adhesive can be expelled from the gap, and the generation of unbonded portions can be suppressed by the air bubbles, thereby ensuring adhesion.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view of an optical module according to the first embodiment of the present invention. This optical module includes a light-emitting side mount substrate 1, a light-receiving side mount substrate 3, and an external waveguide substrate 2 in which these mount substrates 1 and 3 are coupled so as to be optically connectable. In the following description, the up and down direction in FIG. 1 is referred to as the up and down direction, the direction orthogonal to the paper surface is referred to as the left and right direction, the left side in FIG.

  The light emitting side mount substrate 1 has a rectangular shape extending in the front-rear direction and has a thickness of about 200 μm to 2 mm. The overall size of the mount substrate 1 varies depending on the elements and components to be mounted.

  The mount substrate 1 needs to be rigid 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 light transmission efficiency from the light emitting element to the light receiving element is required, it is necessary to mount the optical element with high accuracy and to suppress position fluctuation during use as much as possible. For this reason, a silicon substrate is employed as the mount substrate 1.

  In addition, the mount substrate 1 is preferably made of a material having a linear expansion coefficient close to that of a light emitting element 12a described later. In addition to silicon, the mount substrate 1 is made of a compound semiconductor such as GaAs of the same system as the VCSEL material described later. May be.

  On one surface 11 in the thickness direction, which is the upper surface of the mount substrate 1, an IC in which a light emitting element 12a for converting an electric signal into an optical signal and an IC circuit for transmitting the electric signal to the light emitting element 12a are formed. A substrate 4a is mounted.

  In this 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 in addition to the semiconductor laser. However, since there is no directivity, the ratio of light that is optically coupled to the waveguide through a 45 ° mirror surface, which will be described later, is small. In this case, it is advantageous in terms of low price.

  The light emitting element 12a is mounted on the mount substrate 1 by flip chip bonding. In flip chip bonding, the mounting accuracy is higher than that in the case of performing die bonding or wire bonding, and the mounting accuracy of 1 μm or less can be realized by recognizing the alignment mark formed on the chip.

  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 wiring pattern formed on the one surface 11 of the mount substrate 1 with gold bumps (not shown). The IC substrate 4a is mounted on the mount substrate 1 simultaneously with the light emitting element 12a.

  Although not shown, an underfill material is filled between the light emitting element 12a and the mount substrate 1 and between the IC substrate 4a and the mount substrate 1. The underfill material to be filled between the light emitting element 12a and the mount substrate 1 is required to be transparent with respect to the light emission wavelength of the light emitting element 12a, and the VCSEL is required to have a certain degree of elasticity because its characteristics change due to stress. Therefore, for example, a silicone resin is suitable. In addition, as an underfill material filled between the IC substrate 4a and the mount substrate 1, for example, an epoxy-based material can be employed from the viewpoint of mounting strength.

  In addition, a mirror portion 15 for bending the optical path by 90 ° is formed on the mount substrate 1 at a position directly below the light emitting element 12a. The mirror portion 15 can be formed by evaporating gold or aluminum on a 45 ° inclined wall formed on the mount substrate 1. The 45 ° inclined wall can be formed by, for example, anisotropic etching using a potassium hydroxide solution.

  The mount substrate 1 is provided with a waveguide (optical waveguide) 16 that is optically coupled to the light emitting element 12a. The waveguide 16 extends rearward from the mirror portion 15 and extends to the rear end face 10 of the mount substrate 1 as shown in FIGS. 2 (b), 3 (a), and 3 (b). It is.

  The waveguide 16 includes a core portion 17 having a substantially square cross section with a high refractive index through which light propagates, and a clad portion 18 having a lower refractive index than that. A waveguide formed on the mount substrate 1 is formed. It is disposed in the groove 16a.

  The left and right surfaces and the lower surface of the core portion 17 are covered with the clad portion 18. The upper surface, which is one surface in the thickness direction of the core portion 17, is formed substantially flush with the upper surface 11 of the mount substrate 1 and is exposed without being covered by the cladding portion 18.

  In this embodiment, the rear end surface of the core portion 17 in the longitudinal direction is exposed to be substantially flush with the rear end surface of the mount substrate 1. And the rear end surface of this core part 17 comprises the 1st abutting surface 17a abutted with the 2nd abutting surface 21a of the core part 21 of the external waveguide board | substrate 2 mentioned later.

  The sizes of the core portion 17 and the clad portion 18 are determined by giving priority to light efficiency from the distance from the light emitting element 12a to the waveguide 16, the divergence angle of the light emitting element 12a, and the size of the light receiving element described later.

  For example, in a general VCSEL or PD (photodiode) which is a light receiving element used for high-speed transmission of 5 to 10 Gbps or more, the VCSEL has a light emission diameter of 5 to 10 μm and a divergence angle of about 20 °. Since the diameter is about 60 μm, it is preferable that the size of the core portion 17 is 40 μm and the thickness of the cladding portion 18 is 2 to 10 μm.

  In the case of short-distance intra-device data transmission, since the influence of dispersion is small, optical transmission does not require single-mode transmission, and it is advantageous to use a large-sized multimode waveguide that is easy to align. is there. When higher speed is required, a single mode is used, and a VCSEL or PD that is a light source is selected so that it can respond at high speed.

  The mount substrate 1 is provided with fitting recesses 13a and 13b as first fitting portions. When the fitting recesses 13a and 13b are connected to the external waveguide substrate 2, the core portion 17 of the waveguide 16 of the mount substrate 1 and the core portion 21 of the external waveguide of the external waveguide substrate 2 (to be described later) ) Are aligned so as not to deviate from each other in the left-right direction (width direction). In this embodiment, the fitting recess is composed of two parts, a left fitting recess 13 a disposed on the left side of the core portion 17 and a right fitting recess 13 b disposed on the right side of the core portion 17. Yes.

  As shown in FIG. 3A, the left fitting recess 13 a is formed to be recessed from the upper surface 11 and the rear end surface 10 of the mount substrate 1. Further, a left inclined wall 13c and a right inclined wall 13d are provided on the left inner side and the right inner side of the left fitting recess 13a, respectively.

  The left inclined wall 13c is formed as an inclined wall having a predetermined angle with respect to the axis O1 of the core portion 17. The right inclined wall 13c is formed as an inclined wall that is inclined to the opposite side of the left inclined wall 13c with respect to the axis O1 of the core portion 17, and is a mountain whose interval gradually decreases from the rear end face 10 toward the front. It is formed in a shape (tapered shape).

  In this embodiment, the left fitting recess 13a is disposed at a position separated from the axis O1 of the core portion 17 by a distance of about 400 μm. Further, the length before and after the left fitting recess 13a is set to about 300 μm. However, it is not limited to these dimensions and can be appropriately changed.

  The right fitting recess 13b is formed in the left fitting recess 13a and the core portion 17 of the waveguide 16 so as to be symmetrical with respect to the axis O1. More specifically, the right fitting recess 13b includes a right inclined wall 13d and a left inclined wall 13c that are formed in a tapered shape in which the distance from each other gradually becomes smaller from the rear end face 10 toward the front.

  The right inclined wall 13d is formed symmetrically with the left inclined wall 13c of the left fitting recess 13a with respect to the axis O1, and the left inclined wall 13c is formed to the right of the left fitting recess 13a with respect to the axis O1. It is formed symmetrically with the inclined wall 13d.

  Further, an upper surface 11 of the mount substrate 1 is provided with an overlapping surface 14 on which a connecting piece 5 of the external waveguide substrate 2 described later is overlapped, and an adhesive filling recess 19 for filling the adhesive. The overlapping surface 14 is formed in the range of the length of the connecting piece 5 from the rear end surface 10 on the upper surface 11 to the front side.

  The adhesive filling recesses 19 are respectively provided on the left and right sides of the axis O1 of the core portion 17. Each adhesive filling recess 19 includes an adhesive filling portion 19a and a filling port 19b formed to communicate with the adhesive filling portion 19a.

  The adhesive filling portion 19 a is a portion for adhering the connecting pieces 5 and is formed on a part of the overlapping surface 14. The filling port 19b is a portion for filling the adhesive filling portion 19a with an adhesive, and is formed in a part of the non-overlapping portion where the connecting pieces 5 are not overlapped.

  In this embodiment, the adhesive filling recess 19 has a depth from the upper surface of about 50 μm to 300 μm on the rear side away from the fitting recesses 13 a and 13 b, the front and rear length L 1, and the left and right lengths, respectively. The thickness L2 is about 100 μm to 1000 μm.

  Next, returning to FIG. 1, the mount substrate 3 on the light receiving side will be described. The basic configuration of the light receiving side mount substrate 3 is the same as that of the light emitting side mount substrate 1. However, an IC substrate in which a light receiving element 12b for converting an optical signal into an electric signal and an IC circuit for receiving an electric signal from the light receiving element 12b are formed on the upper surface 31 which is one surface of the light receiving side mounting substrate 3. 4b is different from the above-described mounting substrate 1 on the light emitting side. A PD is employed as the light receiving element 12b, and the IC substrate 4b is an element such as a TIA (Trans-impedance Amplifier) that performs current / voltage conversion.

  Next, the external waveguide substrate 2 will be described based on FIG. 1, FIG. 2 (a), and FIG. The external waveguide substrate 2 includes external waveguides that can be optically coupled to the core portion 17 of the waveguide 16 of the light emitting side mount substrate 1 and the core portion 17 of the waveguide 16 of the light receiving side mount substrate 3. Yes. The external waveguide of the external waveguide substrate 2 includes a core part 21 and a clad part 23.

  Further, in this embodiment, the external waveguide constitutes an external waveguide in which the entire external waveguide substrate 2 is composed of the core portion 21 and the clad portion 23, and is in a flexible film shape narrower than the mount substrate 1. It consists of a long one. In addition, the thickness of the external waveguide substrate 2 in this embodiment is about several tens of μm to 500 μm, but when the flexibility and torsion are not required, the thickness equivalent to that of the mount substrate can be allowed.

  Further, as shown in FIG. 4, the core portion 21 of this embodiment is provided over the entire length so that the axis O <b> 2 and the axis of the external waveguide substrate 2 substantially coincide with each other. The front end surface of the core portion 21 in the longitudinal direction constitutes a second abutting surface 21 a that abuts the first abutting surface 17 a of the mount substrate 1, and is substantially flush with the rear end surface 20 of the external waveguide substrate 2. Exposed.

  The clad portion 23 is formed in a plate shape so as to cover the entire circumference of the core portion 21. The core portion 21 and the clad portion 23 constituting the external waveguide of the external waveguide substrate 2 are made of the same material as the core portion 17 and the clad portion 18 of the mount substrate 1. The thickness and width dimensions of the core portion 21 are substantially the same as the thickness and width dimensions of the core portion 17 of the mount substrate 1.

  As shown in FIG. 1, a connecting piece 5 connected to the light emitting side mounting substrate 1 and a connecting piece 5 connected to the light receiving side mount substrate are provided at both ends in the longitudinal direction of the external waveguide substrate 2, respectively. ing. These are symmetrically shaped, and only the connecting piece 5 connected to the light emitting side mounting substrate 1 will be described below, and the description of the connecting piece 5 connected to the light receiving side mounting substrate will be omitted.

  As shown in FIG. 2A, the connecting piece 5 is a plate protruding from the front end face 20 of the external waveguide substrate 2 to the front side with the same width and a predetermined thickness as the external waveguide substrate 2. It consists of a shape. In this embodiment, the connecting piece 5 is made of the same material as that of the cladding part 23 and is formed integrally with the cladding part 23.

  Further, the lower surface 51 (represented on the upper side in FIG. 2A) of the connecting piece 5 is formed substantially flush with the upper surface of the core portion 21. Further, on the lower surface 51 of the connecting piece 5, fitting convex portions 22 a and 22 b as second fitting portions to be fitted into the fitting concave portions 13 a and 13 b of the light emitting side mounting substrate 1 are provided on the lower side (FIG. 2 ( In a), it is provided so as to protrude to the upper side). The fitting projections 22a and 22b are two, a left fitting projection 22a fitted into the left fitting recess 13a of the mount substrate 1 and a right fitting projection 22b fitted into the right fitting recess 13b. It has.

  As shown in FIG. 4, the left fitting convex portion 22a includes a left abutting wall 22c that abuts against the left inclined wall 13c and the right inclined wall 13d of the left fitting concave portion 13a of the light emitting side mounting substrate 1, and a right abutting portion. A wall 22d is provided. The distance from the axis O2 of the core portion 21 of the external waveguide substrate 2 is such that the left inclined wall 13c of the left fitting recess 13a of the mount substrate 1 and the axis O1 of the right inclined wall 13d (see FIG. 3). ) Is set to the same distance.

  Further, the right fitting convex portion 22b includes a left abutting wall 22c and a right abutting wall 22d that abut on the left inclined wall 13c and the right inclined wall 13d of the left fitting concave portion 13a of the light emitting side mounting substrate 1, respectively. ing. The left abutting wall 22c and the right abutting wall 22d have a distance from the axis O2, respectively, such that the left inclined wall 13c of the right fitting recess 13b of the mount substrate 1 and the axis of the right inclined wall 13d respectively. It is set to the same distance as O1.

  Further, on the lower surface 51 of the connecting piece 5, adhesive portions 54 are respectively provided in portions facing the adhesive filling portion 19 a (see FIG. 3A) of the adhesive filling concave portion 19 of the light emitting side mounting substrate 1. Is provided. Each of these bonding portions 54 is provided with an air vent hole 55 for venting air inside the adhesive filling recess 19 when the adhesive filling recess 19 of the mount substrate 1 is filled with the adhesive. ing.

  Further, the air vent hole 55 of this embodiment is formed in a circular shape. The inner diameter of the air vent hole 55 is smaller than the front and rear length L1 and the left and right length L3 (shown in FIG. 5) of the adhesive filling portion 19a, specifically, about 10 μm to 1000 μm.

  In order to connect the mounting substrate 1 on the light emitting side and the external waveguide substrate 2 configured as described above, the fitting convex portions 22a and 22b of the connecting piece 5 are connected to the fitting concave portion 13a of the mounting substrate 1 on the light emitting side. , 13b from the rear side. Accordingly, as shown in FIG. 5, the left contact wall 22c and the right contact wall 22d of the left fitting convex portion 22a of the connecting piece 5, and the left inclined wall of the left fitting concave portion 13a of the light emitting side mounting substrate 1 are provided. 13c and the right inclined wall 13d are the left contact wall 22c of the right fitting convex portion 22b, the right contact wall 22d and the left inclined wall 13c of the right fitting recess 13b of the light emitting side mounting substrate 1 and the right inclined wall 13d. Are in contact with each other almost at the same time, and both are fitted.

  Further, at the time of this fitting, the first butting surface 17a of the core portion 17 of the light emitting side mounting substrate 1 and the second butting surface 21a of the core portion 21 of the external waveguide substrate 2 are butted. As a result, the core portion 17 of the light emitting side mount substrate 1 and the core portion 21 of the external waveguide substrate 2 are optically coupled.

  At that time, since both the core portions 17 and 21 are aligned in the left-right direction by the above-described fitting, the left-right direction (width direction) of the axes O1 and O2 substantially coincide with each other.

  In addition, due to the fitting, the adhesive portion 54 of the connecting piece 5 and the adhesive filling portion 19 a of the adhesive filling concave portion 19 of the mount substrate 1 match.

  At that time, the lower surface 51 of the external waveguide substrate 2 and the upper surface of the core portion 21 of the external waveguide substrate 2 are flush with each other, and the overlapping surface 14 of the mount substrate 1 and the upper surface of the core portion 17 are Since they are flush with each other, the positions in the vertical direction (thickness direction) of the axes O1 and O2 of the core portions 17 and 21 coincide with each other. Therefore, the optical axis can be hardly shifted.

  Then, from this state, for example, an adhesive is put into the filling port 19b of each adhesive filling recess 19. As a result, the adhesive enters the adhesive filling portion 19a from the filling port 19b by capillary action, and enters the adhesive filling portion 19a by the adhesive. Further, an adhesive is put into the filling port 19b, and as shown in FIGS. 6 (a) and 6 (b), the adhesive is put into the air vent hole 55 from the adhesive filling portion 19a, and further, from the air vent hole 55, The adhesive portion 54 of the connecting piece 5 is arranged so as to be raised on the outer surface side opposite to the adhesive filling portion 19a (the upper surface side opposite to the adhesive portion 54 of the connecting piece 5) and disposed on the outer peripheral portion thereof. By doing so, the adhesive layer 56 having a rivet shape is formed.

  Thereby, the mount board | substrate 1 and the connection piece 5 can be adhere | attached firmly. In addition, even when air bubbles are generated in the adhesive when the adhesive is filled, the air can be expelled from the air vent hole 55, and the adhesive layer 56 can be made free of air bubbles and can be securely bonded.

  In addition, the air vent hole 55 is not limited to a configuration in which only one air vent hole 55 is provided, and can be changed as appropriate. For example, as shown in FIG. 7, the air vent hole 55 is composed of a plurality of air vent holes 55a, The adhesive layer 56a may be formed.

  In addition, the adhesive layer is not limited to a configuration in which the adhesive layer is disposed on the entire peripheral portion of the air vent hole, but may be disposed on a part of the peripheral portion of the air vent hole. Further, as shown in FIG. 8, for example, the adhesive layer 56 delivers the adhesive from the air vent hole 55 to the outer surface of the adhesive portion 54 of the connecting piece 5, and further, from the outer surface, the filling port 19 b of the adhesive filling recess 19. It may be formed in an annular shape surrounding a part of the connecting piece 5.

  In this embodiment, since the adhesive does not enter between the fitting convex portions 22a and 22b of the external waveguide substrate 2 that has been aligned and the fitting concave portions 13a and 13b of the mounting substrate 1 on the light emitting side, The aligned external waveguide substrate 2 and the light emitting side mount substrate 1 are maintained as they are, and the positions of the axes of the core portions 17 and 21 in the left-right direction are shifted by the presence of the adhesive. You can prevent anything.

  In addition, since no adhesive is interposed between the connecting piece 5 of the external waveguide substrate 2 and the upper surface of the mount substrate 1 excluding the adhesive filling recess 19, the vertical direction between the external waveguide substrate 2 and the mount substrate 1 can be reduced. Misalignment can also be prevented.

  Accordingly, the external waveguide substrate 2 and the mount substrate 1 are connected in the vertical and horizontal directions of the respective axes O1 (see FIG. 3A) and O2 (see FIG. 4A) of the core portions 17 and 21 thereof. Can be linked together.

  Further, since the light emitting elements 12a, 12b and the IC substrates 4a, 4b are disposed on the side of the waveguide 16 on the upper surface 11 of the mount substrates 1, 3, the mount substrates 1, 3 and the external waveguide substrate 2 The adhesive used for bonding can be made without any risk of adhesion.

  In this embodiment, an epoxy thermosetting material is used as the adhesive. The adhesive is not limited to an epoxy-based thermosetting material, and for example, a photocurable material can be used. However, when a silicon substrate is used as the mount substrate 1, an uncured portion that is not cured may be generated, and therefore, a thermosetting material is preferably used. However, if the external waveguide is made transparent with respect to the wavelength of photocuring, the uncured portion can be prevented.

  In this embodiment, the photoelectric conversion device has been described as an optical module, but the present invention is applicable to coupling between waveguides formed on two base materials. For example, a passive component having no light receiving and emitting element such as an optical splitter and a waveguide film can be applied.

  Next, the optical module of 2nd Embodiment is demonstrated based on FIG. A marker 191 is provided on the adhesive filling portion 190 a of the adhesive filling recess 190 of the light emitting side mount substrate 101 of the optical module of the second embodiment.

  Specifically, the mounting substrate 101 on the light emitting side is provided with an adhesive filling concave portion 190 as in the first embodiment. And the cross-shaped marker 191 is provided in the adhesive filling part 190a of the recessed part 190 for adhesive filling in this 1st Embodiment, respectively.

  These markers 191 determine whether or not the first abutting surface 17a of the core portion 17 of the light emitting side mounting substrate 101 and the second abutting surface 21a of the core portion 21 of the external waveguide substrate 2 can be aligned. At the same time, it serves as a mark for adjusting the alignment when the alignment is not completed.

  The marker 191 of this embodiment is formed so as to be drawn on the bottom surface of the adhesive filling portion 190a when the adhesive filling portion 190a is formed. The vertical and horizontal dimensions of the marker 191 are set to be substantially the same as the diameter of the air vent hole 55 provided in the connecting piece 5.

  The marker 191 is a marker in a state where the first abutting surface 17a of the core portion 17 of the light emitting side mount substrate 1 and the second abutting surface 21a of the core portion 21 of the external waveguide substrate 2 are abutted with no positional deviation. 191 is arranged at a position where it just enters the air vent hole 55 of the connecting piece 5. Others have the same configuration as that of the first embodiment.

  By providing such a marker 191, it is confirmed whether the marker 191 and the air vent hole 55 of the connecting piece 5 are aligned with each other, so that the first portion 17 of the core portion 17 of the light emitting side mount substrate 1 can be obtained. It is possible to confirm whether or not the abutting surface 17a and the second abutting surface 21a of the core portion 21 of the external waveguide substrate 2 are in an optically coupled state, and can prevent connection in a state where a positional shift has occurred. it can.

  Further, if the positions of the marker 191 and the air vent hole 55 of the connecting piece 5 are not aligned, they may be aligned, thereby optically connecting the first butting surface 17a and the second butting surface 21a. In addition to being able to easily adjust the alignment, the two can be bonded in a state of being reliably aligned.

  Moreover, when using the automatic alignment apparatus using image recognition etc., the marker 191 and the air vent hole 55 of the connection piece 5 can be image-recognized. The marker 191 only needs to be visible from the air vent hole 55. For example, the marker 191 may be a polygonal shape such as a triangle or a quadrangle, or a circular shape. Further, the size of the marker 191 may be larger or smaller than the inner diameter of the air vent hole 55. However, it is preferable that the size be at least visible with a microscope or the like, for example, about 10 μm or more.

  The marker 191 can be formed by machining the mount substrate 1, simultaneously forming a metal plate film by etching, or a waveguide by hot embossing, and processing by anisotropic etching when the mount substrate 1 is made of silicon. , Etc.

  Next, the optical module of 3rd Embodiment is demonstrated based on Fig.10 (a) and FIG.10 (b). A protrusion 291 is provided on the adhesive filling portion 219a of the adhesive filling recess 219 of the light emitting side mount substrate 201 of the optical module of the third embodiment.

  Specifically, the mounting substrate 201 on the light emitting side is provided with an adhesive filling concave portion 219 as in the first embodiment. In the second embodiment, each of the adhesive filling portions 219a of the adhesive filling recess 219 is provided with a truncated cone-shaped protrusion 291.

  Similar to the marker 191 of the second embodiment, these protrusions 291 include a first abutting surface 17 a of the core portion 17 of the light emitting side mounting substrate 101 and a second abutting surface 21 a of the core portion 21 of the external waveguide substrate 2. In addition, it is determined whether or not the alignment is possible and serves as a mark for adjusting the alignment when the alignment is not completed. Further, the protrusion 291 also serves to increase the adhesive strength between the light emitting side mount substrate 201 and the connecting piece 5 without impairing the air vent function of the air vent hole 55.

  The protrusion 291 of this embodiment is a state in which the first butting surface 17a of the core portion 17 of the light emitting side mounting substrate 1 and the second butting surface 21a of the core portion 21 of the external waveguide substrate 2 are butted without misalignment. The shaft O4 is disposed so as to be shifted from the shaft O3 of the air vent hole 55 of the connecting piece 5 by a predetermined distance.

  Further, in the above state, the protrusion 291 and a part of the inner peripheral wall of the air vent hole 55 of the connecting piece 5 come into contact with each other, and there is a gap between the protrusion 291 and the other part of the inner peripheral wall of the air vent hole 55 of the connecting piece 5. 57 is formed. Others have the same configuration as that of the first embodiment.

  By providing such a projection 291, the projection can be used as a marker, and the same effect as that of the second embodiment can be obtained.

  In addition, since the protrusion 291 is configured to contact a part of the inner peripheral wall of the air vent hole 55 of the connecting piece 5, the adhesive strength can be further increased. Further, air bubbles formed in the adhesive can be expelled from the gap 57, and the occurrence of unbonded portions can be suppressed by the air bubbles, thereby ensuring adhesion.

  The outer diameter of the portion of the projection 291 that enters the inner peripheral wall of the air vent hole 55 only needs to be smaller than the inner peripheral wall of the air vent hole 55. Further, the height of the protrusion 291 is preferably higher than the depth of the adhesive filling portion 19a and does not protrude from the outer surface of the connecting piece 5.

  Further, the shape of the protrusion 291 is not particularly limited, and may be triangular thrust, a cylinder, or the like. Further, the method of forming the protrusion may be performed by, for example, machining of the mount substrate 1, processing when the mount substrate 1 is made of silicon, processing by anisotropic etching, simultaneous formation with a waveguide by hot embossing, or the like. it can.

  Moreover, you may use together this protrusion 291 and the marker 191 of the said 2nd Embodiment. For example, the protrusion 291 is provided in the adhesive filling portion 219a of the adhesive filling recess 219 on the left side of the light emitting side mounting substrate 201, and the adhesive filling portion 219a of the right adhesive filling recess 219 is provided in the second embodiment. A marker having the same configuration as the marker 191 may be provided.

  In the first to third embodiments, the mounting recess on the light receiving side is provided with a fitting recess as the first fitting portion, and the connecting piece is provided with a fitting protrusion as the second fitting portion. However, such a fitting portion may not be provided and can be changed as appropriate.

  Moreover, when providing a fitting part, it is good also considering a 1st fitting part as a fitting convex part and a 2nd fitting part as a fitting recessed part. Therefore, it is good also as what provided the fitting convex part in the mount board | substrate of the light emission side, and provided the fitting recessed part in the connection piece.

  In the above embodiment, the connecting piece is provided on the external waveguide substrate. However, the connecting piece may be provided on the light emitting side mounting substrate or the light receiving side mounting substrate, and can be changed as appropriate.

1 is an overall schematic diagram of an optical module according to a first embodiment of the present invention. (A) is the principal part expansion perspective view of the state which turned the external waveguide board upside down, (b) is the principal part expansion perspective view of the mount board | substrate of the light emission side. (A) is a principal part enlarged plan view of the light emitting side mount substrate, (b) is a front view of the light emitting side mount substrate. It is a principal part enlarged plan view of the external waveguide substrate. (A) is an enlarged plan view of a main part in a state where the fitting concave portion of the light emitting side mounting substrate and the fitting convex portion of the connecting piece provided on the external waveguide substrate are fitted, and (b) is a diagram of FIG. It is the VV sectional view taken on the line 5 (a). FIG. 6B is a cross-sectional view taken along the line VI-VI in FIG. 6A, in which a principal part enlarged plan view in a state where the mounting substrate on the light emitting side and the connecting piece are bonded with an adhesive. It is a principal part enlarged plan view of the state where the connecting piece provided with the air vent hole of another embodiment and the mount substrate on the light emitting side are bonded with an adhesive. It is related with explanatory drawing of other embodiment of an adhesive bond layer, (a) is the principal part enlarged plan view of the state which adhere | attached the light emitting side mount board | substrate and the connection piece with the adhesive bond layer of other embodiment, (b) ) Is a cross-sectional view taken along line VII-VII in FIG. It is a principal part enlarged plan view of the state which connected the mount board by the side of light emission which concerns on 2nd Embodiment of this invention, and a connection piece. FIG. 7A is an explanatory view of a third embodiment of the present invention, and FIG. 10A is an enlarged plan view of a main part in a state where the light emitting side mount substrate and a connection piece provided on the external waveguide substrate are connected. FIG. 11 is a cross-sectional view taken along line XX in FIG.

Explanation of symbols

1, 100, 201 Light emitting side mount substrate 2 External waveguide substrate 3 Light receiving side mount substrate 5 Connection piece 13a, 13b Fitting recess (first fitting portion)
17 Core part 21 of waveguide Core parts 22a and 22b of external waveguide Fitting convex part (second fitting part)
55 Air vent hole 57 Clearance

Claims (4)

An optical module that connects a mount substrate provided with an optical waveguide and an external waveguide substrate provided with an external waveguide optically coupled to the waveguide of the mount substrate,
When the waveguide and the external waveguide are optically coupled to one of the mount substrate and the external waveguide substrate, the other of the mount substrate and the external waveguide substrate is selected. There is a connecting piece superimposed on a part,
The connecting piece includes an adhesive portion bonded to the other external waveguide substrate or the mount substrate,
The adhesive module includes at least one air vent hole. The other external waveguide substrate or mount substrate is provided with a concave portion for filling an adhesive on an overlapping surface to be overlapped with an adhesive portion of the connecting piece,
The adhesive filling recess is formed larger than the air vent hole of the bonding portion of the connecting piece superimposed on the overlapping surface, and the inside of the adhesive filling recess and the connecting piece via the air vent hole. Communicates with the outer surface of the
Furthermore, an adhesive layer is provided by bonding the bonding portion of the connecting piece and the other external waveguide substrate or mount substrate,
The adhesive layer is provided with an adhesive from the inside of the concave portion for filling the adhesive through the air vent hole of the connecting piece to at least a part of the peripheral portion of the air vent hole on the outer surface side of the connecting piece. The optical module according to claim 1, wherein the optical module is formed. The other external waveguide substrate or mount substrate is provided with a concave portion for filling an adhesive on an overlapping surface to be overlapped with an adhesive portion of the connecting piece,
The adhesive filling recess is provided with at least one marker,
3. The marker according to claim 1, wherein the marker is disposed at a predetermined position visible from an air vent hole of the connecting piece in a state where the waveguide and the external waveguide are optically coupled. Light module. The other external waveguide substrate or mount substrate is provided with a concave portion for filling an adhesive on an overlapping surface to be overlapped with an adhesive portion of the connecting piece,
The adhesive filling recess is provided with at least one protrusion,
The protrusion abuts on a part of the inner peripheral wall of the air vent hole of the connecting piece in a state where the waveguide and the external waveguide are optically coupled, and another part of the inner peripheral wall of the air vent hole The optical module according to claim 1, wherein a gap is formed between the optical modules.

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