JP4720374B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module.

Conventionally, as shown in FIG. 18, an optical module 8 includes an optical element 5, an optical waveguide substrate 3 optically coupled to the optical element 5, and a wiring substrate 7 on which the optical element 5 and the optical waveguide substrate 3 are mounted. And. The optical waveguide substrate 3 includes a core 2 that guides light inside clads 1a and 1b. In order to optically couple the optical element 5 and the optical waveguide substrate 3 with low loss, a step for positioning the optical element 5 embedded in the heat sink 6 is provided on the substrate 4 that supports the optical waveguide substrate 3. A positioning portion 4a made of a groove is provided. Specifically, the positioning unit 4a positions the optical waveguide substrate 3 through the substrate 4 at a position where the optical axis center of the optical element 5 coincides with the optical axis center of the core 2 in the light input / output unit 2a. (See Patent Document 1).
JP 2004-233687 A

  However, in the background art, the positioning of the optical waveguide substrate 3 and the optical element 5 is performed between the heat sink 6 in which the optical element 5 is embedded and the positioning portion 4a of the substrate 4. If a positional shift occurs during embedding, the optical axis center between the optical element 5 and the core 2 is shifted.

  In addition, since the positioning portion 4a of the substrate 4 is formed by post-processing, high-precision positioning cannot be expected because the processing accuracy greatly affects the positioning accuracy.

  Further, since the positioning portion 4a of the substrate 4 is a step or a groove, a positional shift is likely to occur due to heat generation of the optical element 5 or a change in ambient temperature. In particular, since the optical element 5 is embedded in a heat sink 6 such as glass, a positional shift is likely to occur due to a difference in linear expansion coefficient with respect to a temperature change.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical module capable of positioning the optical axis center between the optical element and the core of the optical waveguide substrate with high accuracy.

In order to solve the above problems, an optical module of the present invention includes an optical element having a light emitting part or a light receiving part, an optical waveguide substrate optically coupled to the optical element, and the optical element mounted thereon. An optical module including a wiring board to be bonded to a board, wherein the optical element is rectangular and mounted on the wiring board, and the optical waveguide board includes a core and a clad that constitutes the core inside. The end of the clad at one end in the extending direction of the core is cut at 45 degrees to form a mirror section reflecting at 90 degrees, and the optical waveguide substrate is a light emitting section or a light receiving section of an optical element. The center of the optical axis is set on the optical element so that the center of the optical axis of the core reflected by 90 degrees on the mirror part coincides, and the lower part of the clad of the optical waveguide substrate has a rectangular shape. Fitting directly to the opposite end of the optical element Integrally forming a positioning portion is a recess that engages Te, by the positioning unit, in which the optical device is characterized in that for positioning in one direction perpendicular to the direction in which the light-emitting or receiving.

  In order to improve the optical coupling efficiency between the optical element and the optical waveguide substrate, the core includes an optical input / output unit, and an extended core extending from the optical input / output unit to the vicinity of the optical element is provided. It is preferable to do.

  In order to improve the optical coupling efficiency between the optical element and the optical waveguide substrate, it is preferable that the optical element and the optical waveguide substrate are directly bonded using a sealing agent that seals the optical element.

  In order to facilitate handling of the optical waveguide substrate, the optical waveguide substrate is preferably configured to be a flexible film.

  In order to improve the optical coupling efficiency, when another optical waveguide substrate is connected to the end of the optical waveguide substrate opposite to the optical element, a connector portion is integrally formed at the opposite end, It is preferable that the connector portion is integrally formed at the end portion of the other optical waveguide substrate, and the connectors are coupled so that the optical axis centers of the cores of both optical waveguide substrates coincide.

  In order to improve the optical coupling efficiency, when another optical element is connected to the end of the optical waveguide substrate opposite to the optical element, the optical waveguide substrate is directly engaged with the other optical element. It is preferable that the positioning portion is integrally formed and at least one core connects between the optical element and another optical element.

  In order to suppress a decrease in optical coupling efficiency even if a positional deviation occurs, the positioning unit performs positioning in one direction orthogonal to the direction in which the optical element emits light or receives light, and the core is It is preferable to make the shape such that the dimension in the direction substantially perpendicular to the one direction increases as the optical element is approached.

According to the present invention, the positioning portion, which is the concave portion of the clad of the optical waveguide substrate, is only set so as to be directly engaged (fitted) with the opposing end portions of the rectangular optical element mounted on the wiring substrate. in, this positioning part, because the optical element can be positioned in one direction perpendicular to the direction in which the light-emitting or receiving, coincide with the center of the optical axis of the optical axis center and the core of the light-emitting portion or the light receiving portion of the optical element As a result, positioning can be performed with high accuracy, so that the optical coupling efficiency between the optical element and the optical waveguide substrate is improved.

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

  1A and 1B show an optical module 10A according to the first embodiment, where FIG. 1A is a side view and FIG. 1B is a plan view. 2A and 2B show the optical element 12 and the optical waveguide substrate 15, wherein FIG. 2A is a perspective view in an exploded state and FIG. 2B is a perspective view in a combined state.

  The optical module 10 </ b> A includes an optical element 12, an optical waveguide substrate 15, and a printed wiring board 11 (the same applies to each optical module according to an embodiment described later).

  The optical element 12 mounted at a predetermined position on the printed wiring board 11 is, for example, a VCSEL (Vertical Cavity Surface Emitting Laser). This VCSEL has, for example, an outer diameter of 0.27 × 0.22 mm, a height of 0.185 mm, a light emitting area of 15 μmφ, and an oscillation wavelength of 850 nm.

  The bonding pad 12 a of the optical element 12 is electrically connected to the electric wiring 11 a on the printed wiring board 11 by wire bonding 13.

  The optical waveguide substrate 15 includes a core 16 and a clad 17, and a mirror portion 15a and a positioning portion 15b are formed. The core 16 that guides light is formed inside the clad 17. The refractive index of the core 16 is 1.53, for example, and the refractive index of the clad 17 is 1.51, for example.

  The core 16 is, for example, 40 μm □. The thickness of the clad 17 is, for example, 20 μm at the lower part close to the optical element 12 and 40 μm at the upper part. The width of the optical waveguide substrate 15 is, for example, 200 μm. Thus, when the thickness of the optical waveguide substrate 15 is thin, it becomes a flexible film and can be bent.

  The end of the clad 17 at one end in the extending direction of the core 16 (left end in FIG. 1) is cut at 45 degrees to form a mirror portion 15a reflecting 90 degrees. The cut surface is coated with a metal film or a dielectric film to improve the reflectance.

  The optical axis center of the light emitting part 12b of the optical element 12 (see FIG. 2A) and the optical axis center of the core 16 reflected by 90 degrees on the mirror part 15a are aligned on the optical element 12. When the waveguide substrate 15 is set, the optical element 12 and the optical waveguide substrate 15 are optically coupled. The light emitted right above the light emitting portion 12b is reflected by the mirror portion 15a in the 90-degree direction as indicated by an arrow, and the other end portion in the core 16 extending direction in the core 16 (FIG. 1). Then, it is propagated in the direction of the right end).

  Here, in order to make the optical axis center of the light emitting part 12 b coincide with the optical axis center of the core 16, a positioning part 15 b that is directly engaged with the optical element 12 is integrally formed under the cladding 17. The positioning portion 15b is a recess that directly engages (fits) the opposing end portions 12c and 12d of the rectangular optical element 12. That is, the positioning portion 15b performs positioning in one direction (in this embodiment, the extending direction of the core 16) orthogonal to the direction in which the optical element 12 emits light.

And the positioning part 15b which is the recessed part of the clad | crud 17 of the optical waveguide board | substrate 15 is directly engaged (fitted) with the edge parts 12c and 12d which the square-shaped optical element 12 mounted on the printed wiring board 11 opposes. Since the positioning unit 15b can be positioned in one direction orthogonal to the direction in which the optical element 12 emits light, the center of the optical axis of the light emitting unit 12b of the optical element 12 and the light of the core 16 can be obtained. and it is matched with the axial center, so it becomes possible to position with high accuracy, the optical coupling efficiency between the optical element 12 and the optical waveguide substrate 15 is improved.

  Since the optical waveguide substrate 15 is a flexible film, the optical waveguide substrate 15 can be easily handled. In other words, the optical waveguide substrate 15 can be mounted on the optical element 12 without interfering with other mounting components on the printed wiring board 11.

  FIG. 3 is a side view of an optical module 10A ′ according to a modification of the first embodiment, and is set on the printed wiring board 11 with the optical waveguide board 15 turned upside down. In this case, the optical element 12 may be electrically connected to the electric wiring 11a on the printed wiring board 11 by the bump 18 or the like.

  In each of the optical modules 10A and 10A ′, the optical element 12 is generally sealed with a sealant for the purpose of ensuring reliability after being mounted on the printed wiring board 11 (according to embodiments described later). The same applies to optical modules.) This sealant is also required to have optical characteristics. However, since the distance through which light is propagated is on the order of several hundred μm, if the optical characteristics are not extremely bad, the optical element 12 can be obtained using this sealant. When the optical waveguide substrate 15 and the optical waveguide substrate 15 are directly joined, the optical coupling efficiency between the optical element 12 and the optical waveguide substrate 15 is improved.

  Next, a method for manufacturing the optical module 10A of the first embodiment will be described with reference to FIGS. Since the base substrate 20 (A, B) to be used differs depending on the resin used for the clad 17 (for example, epoxy resin or fluorine polyimide resin), the case of using a photocurable resin and the case of using a thermosetting resin This will be explained separately.

(When using photo-curing resin)
Since the base substrate 20 (A, B) is required to have flatness and transparency, it is preferable to use mirror-finished quartz glass. Moreover, it is necessary to select the resin type of the clad 17 according to the wavelength of the optical signal to be controlled. For example, an epoxy resin is used at a wavelength of 600 to 1000 μm, and a siloxane resin is preferably used at 1300 to 1600 μm.

  (1) As shown in FIG. 4A, a resin for the lower clad 17 is applied on the lower base substrate 20A.

(2) As shown in FIG. 4B, the molding die 21 in which the groove pattern 21a of the core 16 is formed is pressed against the resin for the lower clad 17, and in this state, ultraviolet rays are emitted from the lower base substrate 20A side, for example. The resin for the lower clad 17 is cured by irradiation for 10 minutes with an intensity of 30 mW / cm ² , and then the molding die 21 is released. Depending on the resin used, adhesion between the lower clad 17, the core 16, and the upper clad 17 may become a problem. In order to suppress the occurrence of delamination between the layers, it is preferable to take a method of improving the adhesion between the respective layers by performing plasma treatment after curing of each resin. As the plasma conditions, for example, the conditions of 10 Pa, 100 W, and 90 seconds in an Ar atmosphere are appropriate so as not to roughen the resin surface.

  (3) After filling the resin for the core 16 into the groove pattern of the core 16 formed in the lower clad 17 and discharging the excess resin by squeezing with the blade 22 as shown in FIG. The resin for the core 16 is cured by irradiating ultraviolet rays from the lower base substrate 20A side under the same conditions as in the step (2).

  (4) As shown in FIG. 4D, after the resin for the upper clad 17 is applied on the lower clad 17, the upper base substrate 20B is pressed against the resin for the upper clad 17 The resin for the upper clad 17 is cured by irradiating ultraviolet rays from the upper base substrate 20B side under the same conditions as in the step (2).

  (5) As shown in FIG. 5A, the upper and lower base substrates 20A and 20B are separated from the lower clad 17 and the upper clad 17, and the shapes of the mirror portion 15a, the positioning portion 15b, etc. are cut and polished. Machining with Further, a metal film or a dielectric film is coated on the mirror portion 15a.

  (6) The optical element 12 is mounted on the printed circuit board 11 as shown in FIG. Mounting is performed by, for example, die bonding and wire bonding.

  (7) As shown in FIG. 5C, the optical waveguide substrate 15 manufactured in the step (5) is set on the optical element 12 mounted on the printed wiring board 11. The optical element 12 and the optical waveguide substrate 15 are bonded using an optical adhesive, or the resin serving as the sealing agent of the optical element 12 described above is bonded instead of the adhesive. In addition, it is preferable to use the photocurable adhesive agent of an epoxy resin as an optical adhesive agent, and it is preferable to match | combine the refractive index with clad resin.

(When using thermosetting resin)
Since the base substrate is not required to be transparent, it is preferable to use a mirror-finished silicon substrate. The thickness of the resin material and the optical waveguide substrate is the same as in the case of using the photocurable resin. The step (1) is the same. In the step (2), the molding die 21 in which the groove pattern of the core 16 is formed is pressed against the resin for the lower clad 17 and heated in an oven at 100 ° C. for 1 hour, for example. The resin for the clad 17 is cured, and then the molding die 21 is released.

  In the step (3), the resin for the core 16 is filled in the groove pattern of the core 16 formed in the lower clad 17, and excess resin is discharged by squeezing with the blade 22. The resin for the core 16 is cured by heating in an oven for 1 hour.

  In the step (4), after the resin for the upper clad 17 is applied on the lower clad 17, the upper base substrate 20B is pressed against the resin for the upper clad 17 and, for example, 100 ° C. Heat in an oven for 1 hour to cure the resin for the upper clad 17. The steps (5) to (7) are the same.

  When the manufacturing method of the optical module 10A for optically coupling the optical element 12 and the optical waveguide substrate 15 is summarized, a groove for the core 16 is formed in the lower clad 17 together with the lower clad 17 using the molding die 21. A step of forming the core 16 with the groove for the core 16, a step of forming the upper clad 17 on the core 16, a step of forming an end face to form the mirror portion 15a, It includes a step of forming the positioning portion 15b by processing the clad 17, and a step of bonding the optical element 12, the optical waveguide substrate 15 and the printed wiring board 11 so as to bond the optical element 12 to the positioning portion 15b. .

  The last step is a method of joining the optical waveguide substrate 15 and the optical element 12 in advance and then joining to the printed wiring board 11, and the optical element 12 after joining the optical waveguide substrate 15 and the printed wiring board 11 in advance. Any of a method of bonding the optical waveguide substrate 15 after the optical element 12 and the printed wiring board 11 are bonded in advance may be used.

  FIG. 6 is a side view of the optical module 10B of the second embodiment. The difference from the optical module 10 </ b> A of the first embodiment is that an extended core 16 ′ extending from the light input / output unit 16 a to the vicinity of the optical element 12 is provided.

  That is, as in the optical module 10A of the first embodiment, when only the lower clad 17 is between the mirror portion 15a and the optical element 12, light spreads in the lower clad 17 and the optical coupling efficiency is lowered. To do. Therefore, by providing the extended core 16 ′ extending from the light input / output unit 16 a to the vicinity of the optical element 12, light does not spread in the lower clad 17, so that the light between the optical element 12 and the optical waveguide substrate 15 can be reduced. The coupling efficiency is improved.

  The manufacturing method of the optical module 10B of the second embodiment is the same as the manufacturing method of the optical module 10A of the first embodiment. However, the molding die 21 in the step (2) includes a molding die 21 shown in FIG. Thus, the groove pattern 21a of the core 16 and the hole pattern 21b of the extended core 16 ′ are formed, respectively.

  Further, in the step (3), when filling the hole pattern of the extended core 16 'with resin, it is preferable to take time so that bubbles do not enter (see FIG. 8B). In some cases, after applying the resin, defoaming may be performed in a vacuum chamber. The step (4) is shown in FIG. 8C, and the step (5) is shown in FIG. 8D. The steps (6) and (7) are the same.

  FIG. 7 is a side view of an optical module 10B ′ according to a modification of the second embodiment, in which the optical waveguide substrate 15 is disposed so as to be perpendicular to the optical element 12 and is approximately 90 degrees together with the cores 16 and 16 ′. It is bent. In the case where the light emitting direction of the optical element 12 and the light propagation direction of the cores 16 and 16 ′ coincide, it is not necessary to bend the optical waveguide substrate 15 as indicated by a two-dot chain line a.

  In this case, as described in the optical module 10A of the first embodiment, if the thickness of the optical waveguide substrate 15 is thin, it becomes flexible and can be bent. Depending on the difference in refractive index between 16 'and clad 17, light may leak. For example, the refractive index of cores 16 and 16' is 1.56 and the refractive index of clad 17 is 1.51. It is preferable to increase the difference in rate. Due to this difference in refractive index, for example, even when the bending radius is R = 10 mm, there is no light leakage, and good light propagation characteristics can be obtained.

  With this optical module 10B ′, the light input / output unit 16a does not require the mirror unit 15a, and therefore there is no light loss that occurs when the mirror unit 15a is provided, so that light can be extracted with high efficiency. .

  Here, in the manufacturing method of the optical modules 10A and 10B of the first and second embodiments, the shape of the positioning portion 15b is machined by cutting and polishing in the step (5). As shown in FIG. 5, in the step (1), when the resin for the lower clad 17 is applied on the lower base substrate 20A, the positioning portion 15b can be formed at the same time.

  That is, as shown in FIG. 9A, an uneven portion 20a for forming the positioning portion 15b is formed in advance on the lower base substrate 20A. The concavo-convex portion 20a can be formed by a method of machining or a method of applying a resist on the lower base substrate 20A and exposing and developing a pattern.

  Then, as in the step (1), a resin for the lower clad 17 is applied on the lower base substrate 20A. In particular, when filling the concavo-convex portion 20a with resin, it is preferable to take time so that bubbles do not enter. In some cases, after applying the resin, defoaming may be performed in a vacuum chamber.

  Next, as shown in FIG. 9B, as in the step (2), the molding die 21 in which the groove pattern 21a of the core 16 is formed is pressed against the resin for the lower clad 17. In this case, the thickness of the clad 17 is controlled to be constant by managing the gap between the molding die 21 and the lower base substrate 20A. The management of the gap may be management using the spacer portion 21c around the molding die 21 or a method of detecting the elevation position of the molding die 21.

  The step (3) is shown in FIG. 9 (c), the step (4) is shown in FIG. 9 (d), and the step (5) is shown in FIG. 9 (e). The steps (6) and (7) are the same.

  Thus, when the resin for the lower clad 17 is applied onto the lower base substrate 20A, the manufacturing process can be reduced by simultaneously forming the positioning portion 15b.

  Here, in the manufacturing method of the optical modules 10A and 10B of the first and second embodiments, the shape of the mirror portion 15a is machined by cutting and polishing in the step (5). As shown in FIG. 5, in the step (1), when the molding die 21 is pressed against the resin for the lower clad 17, the mirror portion 15a can be formed simultaneously.

  That is, as shown in FIG. 10A, a mirror inclined portion 21d for forming the mirror portion 15a on the forming die 21 is formed in advance. Then, as in the step (2), the molding die 21 in which the groove pattern 21 a of the core 16 and the mirror inclined portion 21 d are formed is pressed against the resin for the lower clad 17.

  The step (3) is shown in FIG. 10B, and the step (4) is shown in FIG. 10C. The steps (5) to (7) are the same.

  In this way, when the molding die 21 is pressed against the resin for the lower clad 17, the manufacturing process can be reduced by forming the mirror portion 15a at the same time.

  As shown in FIG. 10 (d), the relationship between the mirror portion 15a and the core 16 is enlarged, and there is a resin b of the clad 17 between the end portion of the core 16 and the mirror portion 15a for convenience of molding. As shown in the arrow, that is, the enlarged view of the portion A, the light propagating through the core 16 is slightly reflected by the resin b of the clad 17, but most of the light propagates to the clad 17 and becomes a mirror portion. Since it is reflected at 15a, there is no problem.

  FIG. 11A shows another optical waveguide substrate connected to the optical waveguide substrate 15 of the optical module 10A of the first embodiment [optical element / optical waveguide substrate / optical waveguide substrate (optical fiber)] of the third embodiment. FIG. 11B shows an optical module 10C, and FIG. 11B shows a fourth embodiment in which another optical element is connected to the optical waveguide substrate 15 of the optical module 10A of the first embodiment (optical element / optical waveguide substrate / optical element). In these optical modules 10D, the optical coupling efficiency with other parts becomes a problem in these connections.

  In the optical module 10 </ b> C of the third embodiment in FIG. 11A, the connector 16 </ b> A is integrally formed of the same material as that of the clad 17 at the other end (right end) in the extending direction of the core 16. The connector portion 15A is extended to the right end portion of the connector portion 15A, and the connector portion 24A is integrally formed at the end portion of the optical fiber 24 with the same material as that of the clad 17 so that the fiber 25 extends to the left end portion of the connector portion 24A.

  Guide holes 15c and 24a are formed in the connector parts 15A and 24A, respectively, and the connector parts 15A and 24A are brought close to each other while the guide pins 26 are inserted into the guide holes 15c and 24a. , 24A can be combined. In this connector coupling portion, the center of the optical axis between the core 16 and the fiber 25 can be positioned with high accuracy.

  In the optical module 10D of the fourth embodiment shown in FIG. 11B, the printed wiring board 11 is elongated in the extending direction of the core 16 of the optical waveguide board 15, and an optical element is formed on one side (left side) of the printed wiring board 11. (For example, a VCSEL as a light emitting element) 12 is disposed, and an optical element [for example, a PD (photodiode) as a light receiving element] 12 ′ is disposed on the other side (right side), and at least one core 16 is interposed therebetween. Connecting. In this optical waveguide substrate 15, since there is at least one core 16, the problem of mismatch of the optical axis centers does not occur. Note that when one signal is branched and a signal is sent to two or more detectors, there may be two or more cores 16.

  FIG. 12A is a plan view of an optical module 10E according to the fifth embodiment, and FIG. 12B is a cross-sectional view taken along line AA in FIG. In the present embodiment, the left-right direction in FIG. 12A is referred to as the front-rear direction, and the up-down direction is referred to as the left-right direction.

  In the optical module 10 </ b> E, the optical waveguide substrate 15 holds the wiring substrate 11. Specifically, the optical waveguide substrate 15 is formed with a recess portion 15h that is recessed in a substantially rectangular shape in plan view from the upper surface, and the wiring substrate 11 is fitted into the recess portion 15h.

  As shown in FIG. 13, the wiring board 11 has a rectangular parallelepiped shape having a cross-sectional shape of about 3 mm □ and extending in the left-right direction. Implemented side by side. A PD amplifier 31 and a VCSEL IC 32 are mounted on the upper surface of the wiring board 11, and each of them is electrically connected to the optical elements 12 and 12 'by an electric wiring 11a. Further, on the lower surface of the wiring substrate 11, groove-shaped recesses 11 b that extend backward from the front surface by a predetermined length and open downward are provided side by side.

  The horizontal dimension of the hollow portion 15 h is set slightly larger than the horizontal dimension of the wiring board 11, but the front-rear dimension is larger than the front-rear dimension of the wiring board 11. Is set. A pair of protrusions 15j are provided at positions corresponding to the optical elements 12 and 12 'on the front edge of the recess 15h, and a positioning part 15b is formed on the protrusion 15j.

  The positioning portion 15b is a concave portion that directly engages (fits) with the upper end portion and the lower end portion of the optical elements 12, 12 ′, and performs positioning in the vertical direction. The core 16 extends forward from the positioning portion 15b. Note that the protruding amount of the upper and lower protrusions of the positioning portion 15b is small. If the wiring board 11 is forcibly fitted into the recess 15h from above, the optical elements 12 and 12 ′ are protruded from the upper protrusion of the positioning portion 15b. The optical elements 12 and 12 ′ are directly engaged (fitted) with the positioning portion 15 b through the portion.

  The core 16 has a constant vertical dimension (height dimension), but in the vicinity of the optical element 12, 12 ′, the horizontal dimension (width dimension) increases as the optical element 12, 12 ′ is approached. It is formed in a taper shape. Specifically, the height dimension of the core 16 and the width dimension of parts other than the taper part are set to about 100 μm, the length of the taper part is set to about 1 mm, and the maximum width dimension is set to about 200 μm. .

  Further, on the bottom surface of the hollow portion 15h, a wiring board engaging positioning portion 15i having a ridge extending in the front-rear direction is provided at a position corresponding to the concave portion 11b of the wiring board 11. The wiring board engaging positioning portion 15i is fitted into and engaged with the concave portion 11b, so that the wiring board 11 and the optical waveguide substrate 15 are in other words, the optical elements 12, 12 'and the core. 16 is positioned in the left-right direction.

  As described above, in the optical module 10E of the present embodiment, the optical elements 12, 12 ′ and the optical waveguide substrate 15 can be positioned in the front-rear direction and the left-right direction by the positioning portion 15b and the wiring board engaging positioning portion 15i. Therefore, the optical axis centers of the optical elements 12, 12 ′ and the core 16 can be positioned with higher accuracy.

  Further, since the core 16 is tapered so that the width dimension increases as it approaches the optical elements 12 and 12 ′, even if the optical elements 12 and 12 ′ and the optical waveguide substrate 15 are displaced in the left-right direction, Since most of the light emitted from the optical elements 12 and 12 ′ is guided into the core 16 by the tapered portion, it is possible to suppress a decrease in the optical coupling efficiency due to the position shift.

  In the optical module 10E, the wiring board 11 is forcibly fitted in the recess 15h. However, like the optical module 10E ′ of the modification shown in FIG. 14, the protruding portion 15j is flexible in the vertical direction. Then, the optical elements 12 and 12 'and the positioning portion 15b can be directly engaged with each other in advance, and can be fitted into the recessed portion 15h in this state.

  Thus, in order to make the protrusion 15j flexible in the vertical direction, it is only necessary to make a cut extending forward on the lower side of the protrusion 15j as shown in FIG. Or the waveguide board | substrate 15 is made into 2 division structure of the main-body part in which the hollow part 15h was formed, and the flexible film-like waveguide part which has the core 16, and this waveguide part protrudes from the edge of the hollow part 15h. As such, it may be joined to the main body.

  In the embodiment, the wiring board engaging positioning portion 15i is a protrusion, but a convex portion is provided on the lower surface of the wiring substrate 11, and the wiring board engaging positioning portion 15i is engaged with the convex portion. It may be a concave shape.

  FIG. 15 is an exploded perspective view of the optical module 10F of the sixth embodiment, FIG. 16 (a) is a plan view, and FIG. 15 (b) is a side view. In this optical module 10 </ b> F, the optical waveguide substrate 15 serves as a connector for connecting the optical element 12 and another optical waveguide substrate 34.

  Specifically, the outer dimensions of the optical waveguide substrate 15 are 5 mm in length, 2 mm in width, and 150 μm in thickness. The central portion of the core 16 in the extending direction is a constricted portion set to a width of 1 mm. The positioning portion 15b is formed at one end (left side) of the constricted portion, and the other (right side) end. The portion is a connector portion 15A. The positioning portion 15b is a groove-like recess extending in that direction so as to be positioned in a direction orthogonal to the extending direction of the core 16, and a cross section in a direction orthogonal to the extending direction of the core 16 of the connector portion 15A. The shape is a trapezoid whose bottom is shorter than the top.

  Similar to the optical waveguide substrate 15, the optical waveguide substrate 34 includes a core 35 and a clad 36. One end portion (left end portion) of the optical waveguide substrate 34 is cut out to form a connector portion 34A. Both side surfaces of the connector portion 34A are inclined surfaces, and the connector portion 15A of the optical waveguide substrate 15 can be fitted into and engaged with the connector portion 34A from above. In the engaged state, The optical axis centers of the cores 16 and 35 coincide with each other.

  And in the state which arranged the wiring board 11 and the optical waveguide board | substrate 34 in parallel, while arrange | positioning the optical waveguide board | substrate 15 on it, the positioning part 15b is directly engaged with the optical element 12, and the connector part 15A is connected to the connector part. By fitting into 34 </ b> A, the optical waveguide substrate 34 and the optical element 12 are optically coupled via the optical waveguide substrate 15. The optical waveguide substrates 15 and 34 are fixed using an acrylate-based optical adhesive after the optical waveguide substrate 15 is disposed. As this optical adhesive, one having the same refractive index as that of the core 16 is used.

  The constricted portion is in the form of a flexible film and has a structure that facilitates alignment for coupling with the optical element 12 and the optical waveguide substrate 34. That is, even if a positional deviation with respect to the optical element 12 or the optical waveguide substrate 34 occurs, the constricted portion moves, so that the overall positional deviation does not occur.

  In this way, the optical waveguide substrates 15 and 34 can be optically coupled at low cost without using connectors or guide pins. Further, since the connector portions 15A and 34A of the optical waveguide substrates 15 and 34 can be positioned with high accuracy, the optical coupling efficiency can be improved also in the coupling. In the sixth embodiment, the core 16 of the optical waveguide substrate 15 has a straight shape, but may have a tapered shape as in the optical module 10E of the fifth embodiment.

  FIG. 17 is a side view of an optical module 10F ′ according to a modification of the sixth embodiment. A connector portion 34A is also formed on the other end portion (right end portion) of the optical waveguide substrate 34. The connector portion 15A of the optical waveguide substrate 15 optically coupled to the optical element 12 ′ is fitted. As described above, by forming the connector portions 34A at both ends of the other optical waveguide substrate 34, the optical elements 12 and 12 'can be connected by the optical waveguide substrate 15 and the optical waveguide substrate 34. .

It is an optical module which concerns on 1st Embodiment of this invention, (a) is a side view, (b) is a top view. It is an optical element and an optical waveguide board, (a) is a perspective view of an exploded state, and (b) is a perspective view of a combined state. It is a side view of the optical module of the modification of 1st Embodiment. (A)-(d) is the first half process drawing of the manufacturing method of the optical module which concerns on 1st Embodiment. (A)-(c) is the latter-half process drawing of the manufacturing method of the optical module which concerns on 1st Embodiment. It is a side view of the optical module which concerns on 2nd Embodiment of this invention. It is a side view of the optical module of the modification of 2nd Embodiment. (A)-(d) is a principal part process drawing of the manufacturing method of the optical module which concerns on 2nd Embodiment. (A)-(e) is process drawing which forms the positioning part of an optical waveguide board | substrate simultaneously. (A)-(c) is process drawing which forms the mirror part of an optical waveguide board | substrate simultaneously, (d) is the A section enlarged view of (c). (A) is a side view of the optical module of 3rd Embodiment, (b) is a side view of the optical module of 4th Embodiment. (A) is a top view of the optical module which concerns on 5th Embodiment of this invention, (b) is the sectional view on the AA line of (a). It is the perspective view which showed the wiring board schematically. It is an exploded sectional view of the optical module of the modification of a 5th embodiment. It is a disassembled perspective view of the optical module which concerns on 6th Embodiment of this invention. (A) is a top view of the optical module of 6th Embodiment, (b) is a side view of the optical module of 6th Embodiment. It is a side view of the optical module of the modification of 6th Embodiment. It is a side view of the conventional optical module.

Explanation of symbols

10A, 10A ', 10B, 10B', 10C, 10D, 10E, 10E ', 10F, 10F' Optical module 11 Printed wiring board 11b Recess 12 Optical element (VCSEL)
12 'optical element [PD (photodiode)]
15 Optical waveguide substrate 15a Mirror portion 15b Positioning portion 15A Connector portion 15h Depression portion 15i Positioning portion for wiring board engagement 16 Core 16 ′ Extension core 16a Light input / output portion 17 Clad 24 Optical fiber 24A Connector portion 34 Optical waveguide substrate 34A Connector portion

Claims (7)

An optical module comprising: an optical element having a light emitting part or a light receiving part; an optical waveguide substrate optically coupled to the optical element; and a wiring board on which the optical element is mounted and joined to the optical waveguide substrate. And
The optical element has a quadrangular shape and is mounted on a wiring board, and the optical waveguide substrate includes a core and a clad that constitutes the core inside.
The end of the clad at one end in the extending direction of the core is cut at 45 degrees to form a mirror part that reflects 90 degrees,
The optical waveguide substrate is set on the optical element so that the optical axis center of the light emitting part or the light receiving part of the optical element coincides with the optical axis center of the core reflected by 90 degrees on the mirror part. the bottom of the cladding of the optical waveguide substrate, and integrally forming a positioning portion is a recess that engages directly fitted to the opposite ends of the optical element is a rectangular shape, by the positioning unit, the optical element emits light or An optical module characterized in that positioning is performed in one direction orthogonal to a light receiving direction.   The optical module according to claim 1, wherein the core includes an optical input / output unit, and an extended core extending from the optical input / output unit to the vicinity of the optical element is provided.   The optical module according to claim 1, wherein the optical element and the optical waveguide substrate are directly bonded using a sealant that seals the optical element.   The optical module according to claim 1, wherein the optical waveguide substrate has a flexible film shape.   When another optical waveguide substrate is connected to the end of the optical waveguide substrate opposite to the optical element, a connector portion is integrally formed at the opposite end, and at the end of the other optical waveguide substrate. 5. The light according to claim 1, wherein the connectors are integrally formed so that the connectors are coupled so that the optical axis centers of the cores of both optical waveguide substrates coincide. module.   When connecting another optical element to the end of the optical waveguide substrate opposite to the optical element, a positioning portion that is directly engaged with the other optical element is integrally formed on the optical waveguide substrate, The optical module according to any one of claims 1 to 5, wherein the element and another optical element are connected by at least one core.   The positioning portion performs positioning in one direction orthogonal to the direction in which the optical element emits light or receives light, and the dimension of the core in a direction substantially orthogonal to the one direction as approaching the optical element. The optical module according to any one of claims 1 to 6, wherein the optical module has a shape that increases.

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