JP2007264286A - Method of manufacturing optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assemble a light receiving/emitting element into a self-forming optical waveguide without any deviation in the optical axis. <P>SOLUTION: Wavelength selective mirrors 31, 32 are erected in a container piece 10. Mold sections 21, 22 are fitted together to form a housing M, with a first photosetting resin liquid filled. Light is emitted from an optical fiber 100 inserted into a through hole 101 and from the light guiding parts 211, 221, 222 of the mold sections to form a core. With the unhardened first photosetting resin liquid removed, the second photosetting resin liquid is filled to form a clad 50c, so that projections from 511-1 to 522-2 are formed on the surface of the clad 50c. The projections 511-1 and 511-2 on the surface of the clad 50c and a core end 411-f are positioned by the light guiding part 211 of the mold section 21 and the recesses 211-1 and 211-2. By designing the light guiding part 211 of the mold section 21 and the recesses 211-1 and 211-2 correspondingly to the effective face and the recesses of the light receiving/emitting element to be assembled, the assembling and the optical coupling of the light receiving/emitting element are accomplished. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical module in which a light receiving element and / or a light emitting element and other optical elements are assembled in a self-forming optical waveguide.

  The inventors have proposed various self-forming optical waveguides in which curing wavelength light is introduced into a photocurable resin liquid and the photocurable resin liquid is cured in a self-collecting manner to form an axial core. Yes. For example, the following Patent Documents 1 to 3 and Non-Patent Document 1. According to these techniques, an optical fiber is fixed to a transparent container to serve as an introduction end of resin curing wavelength light, and a core is grown from the end face of the optical fiber, so that there is no deviation between the optical fiber end and the optical axis. An optical waveguide having a core made of this resin can be easily formed. After forming such an optical waveguide, an optical module can be easily assembled by assembling a light receiving element or a light emitting element (hereinafter simply referred to as “light emitting / receiving element”) outside the transparent container where the core end (growth end) has reached. Can be configured.

  When the light emitting / receiving element is assembled after the optical waveguide is formed, the optical axis at the end of the optical waveguide needs to coincide with the optical axis of the light receiving / emitting element. When the light emitting element is assembled, an active alignment method can be used. In this method, the light emitted from the light emitting element is incident on the optical waveguide, and the output intensity of the light emitted from the other end is measured. In this method, the optical waveguide is fixed at a position where good optical coupling efficiency can be obtained.

There is also a passive alignment method in which the optical axis is adjusted by the assembly itself. Although the best optical coupling efficiency cannot be obtained, this method is excellent in low cost and mass productivity when a slight decrease in optical coupling efficiency is not a problem (such as an optical communication module for short-distance transmission). Patent Document 4 discloses a method of using an alignment jig so that the optical axes of optical fibers and optical elements are aligned with each other, and further fixing them with a photocurable resin. In patent document 5, the structure for alignment is integrally formed in the optical module housing. Specifically, the element is positioned by fitting the other alignment pin into the fitting hole of one. A method of fixing in a state is disclosed. In Patent Document 6, by providing a guide pin in a mold mold filled with a photopolymerizable material, the photopolymerizable material is irradiated with light to produce an optical waveguide on the light receiving and emitting element, and at the same time, A method for producing a fitting hole that serves as a reference for alignment is disclosed.
Japanese Patent No. 3444352 JP 2001-242353 A JP-A-11-326660 JP-A-2005-208612 JP 2001-154066 A Special Solution 2004-240315 M. Yonemura et.al., Optics Letters, vol. 30, no. 17, pp. 2206-2208, 2005

  The active alignment method provides high optical coupling efficiency, but requires an optical axis adjusting device and takes time to adjust the optical axis, and thus has a problem in cost and mass productivity. Further, in the passive alignment method, if each optical axis is not accurately determined so as to be a predetermined position with respect to the outer shape or the fitting pin, there is a possibility that the optical axis is shifted at the time of assembly. Therefore, it is required that the individual parts are manufactured with high shape (position) accuracy, leading to high costs.

Further, the self-forming optical waveguide has the following problems.
First, when a waveguide is manufactured with light emitted from an optical fiber, a shift occurs in the growth direction of the waveguide due to fluctuation (convection) of the resin liquid during the self-forming process, and the end position of the waveguide is stabilized. There wasn't. Therefore, even when passive alignment is performed, the coupling efficiency with the light emitting / receiving element is not stable.
Second, there was no highly accurate reference that could be aligned with the optical axis of the optical waveguide. Conventionally, the position of the waveguide is set based on the outer shape of the transparent casing, but it is not practical because the manufacturing accuracy of the transparent casing is unstable.
Third, the wall thickness of the transparent container creates a region where light can freely propagate between the waveguide and the light emitting / receiving element, which is a factor in reducing optical coupling efficiency.

  The inventors of the present invention have completed the present invention by intensively studying a method for assembling a light receiving / emitting element or the like at the end of a self-forming optical waveguide, in order to reduce the cost of the optical module, improve the mass productivity, and improve the optical coupling efficiency. That is, an object of the present invention is to facilitate the mounting process of an optical element (light emitting / receiving element or the like) in order to improve the mass productivity of an optical module using a self-forming optical waveguide. Another object is to improve the optical coupling efficiency in an optical module using a self-forming optical waveguide.

  The invention according to claim 1 is a light having a shaft-like core obtained by self-condensing a photo-curable resin liquid, an optical waveguide including a clad covering the core, and one or more optical elements. In a module manufacturing method, a mold part for forming a predetermined positioning structure for mounting an optical element on a clad and a case capable of holding a photocurable resin liquid are formed by combining the mold part with the mold part. The photocurable resin liquid is held in a casing obtained by combining the mold part and the container piece, and is introduced from two or more locations including at least the light introducing part positioned by the mold part. A step of forming an axial core by curing with light of a predetermined wavelength, a step of forming a clad having a predetermined structure for positioning using a mold portion, and a step of removing the mold portion from the optical waveguide , Formed on the cladding A step of attaching at least one optical element using the predetermined positioning structure, and the optical axis of the optical element is formed by the curing wavelength light introduced from the light introduction part of the mold part. An optical module manufacturing method characterized in that the optical axis coincides with the optical axis of the core end.

  The invention according to claim 2 is characterized in that the optical element is a light emitting element, a light receiving element, or an optical waveguide and a connection structure provided at an end thereof. According to a third aspect of the present invention, the optical module has one or more branches, and has a wavelength selective mirror for each branch point, and the wavelength selective mirror has a transmittance with respect to the curing wavelength light. And the reflectance is 20% or more, and the one or more wavelength-selective mirrors are fixed to the container piece, and then the photocurable resin liquid is introduced. The invention according to claim 4 is characterized in that at least one optical fiber is fixed to the container piece, and curing wavelength light is introduced into the photocurable resin liquid through the optical fiber.

  In the invention according to claim 5, the predetermined structure for positioning for attaching the optical element is due to the concave portion and / or convex portion formed on the surface of the clad by transferring the convex portion and / or concave portion of the mold portion. It is characterized by being. The concave portions and / or convex portions formed on the surface of the clad are fitted with the corresponding convex portions and / or concave portions on the surface of the optical element in the invention according to claim 6, and are characterized in that: The invention according to the invention is characterized in that it is fitted with the shape of the outer periphery of the optical element.

  In the invention according to claim 8, the predetermined structure for positioning for attaching the optical element is a structure that is held by the mold part before the clad is formed and is fixed to the clad after the clad is formed. It is characterized by that. In the invention according to claim 9, the shape of the exposed portion from the clad of the structure body is fitted with the corresponding convex portion and / or concave portion of the optical element surface, and the invention according to claim 10. Is characterized by being fitted with the shape of the outer periphery of the optical element.

  The invention according to claim 11 is characterized in that the mold part is composed of a plurality of mold pieces and is separable. The invention according to claim 12 is characterized in that at least one light introducing part of the mold part is formed with a concave part for forming a convex lens at the core end part in a part in contact with the end part of the core. To do.

  The mold part has a shape for forming a predetermined positioning structure for attaching the optical element in the clad, and is provided with a light-introducing part for forming a core for forming the core. Therefore, there is no mismatch between the position of the optical axis at the core end, which is the growth start end, and the positioning structure formed in the cladding. That is, by assembling the optical element here, it is possible to minimize the deviation between the optical axis of the core end and the optical axis of the optical element, and the optical element can be assembled easily and accurately. In addition, if the positioning structure provided on the surface of the clad is a fitting structure with the optical element to be assembled, it is possible to assemble the optical element with only a “fitting” operation while minimizing the deviation of the optical axis. And can. In addition, since the core which grows by photocuring from a plurality of locations is easily united by self-alignment even if a slight axial deviation occurs, a desired optical waveguide core can be formed.

  Further, since the coupling portion between the optical waveguide and the optical element is coupled without passing through the wall of the transparent container, the distance between the optical waveguide and the optical element can be shortened, and the optical coupling efficiency is improved. Moreover, since these coupling | bonding is performed by the fitting part which has a three-dimensional structure, there is no possibility that an optical axis shift | offset | difference may arise by receiving external force.

  Thus, the manufacturing process of the optical waveguide device composed of the self-forming optical waveguide and the optical element can be simplified, and the productivity is improved. Further, there is no deviation of the optical axis between the self-forming optical waveguide and the optical element, and the optical coupling efficiency is improved because a transparent container or the like is not interposed between them.

  In addition, by providing the mold part, an arbitrary shape can be formed on the surface of the clad in the part in contact with the mold part. For example, since the light introduction part of the mold part is in contact with the core, the end of the core can be shaped into a convex lens or the like.

  When the core is grown by photocuring from three or more positions including the light introduction part of the mold part, the branching waveguide can be easily formed. If the core is grown after the wavelength selective mirror is arranged at each branch point, the optical modules described in Patent Documents 1 to 3 can be easily formed. At this time, since the optical axis when the optical element such as the light emitting / receiving element is assembled coincides with the growth start point of the core, a multi-branch optical module can be easily formed with high accuracy.

  For the manufacturing method of the self-forming optical waveguide used in the present invention, any prior art by the present applicants can be used. After forming a core using the 1st photocurable resin liquid used as a core material, you may employ | adopt the method of removing a 1st photocurable resin liquid uncured and filling a clad material. In this case, the method for curing the clad material is arbitrary. If the second photocurable resin liquid is used as the clad material, the first photocurable resin liquid is compatible with the first photocurable resin liquid and can be copolymerized. The cleaning step after the exclusion can be omitted.

  Two-stage photocuring by selecting a photopolymerization initiator so that each curing wavelength is different, using a mixture of two types of photocurable resin liquids with different refractive indices without copolymerization (different polymerization mechanisms) Thus, the applicants of the present application have proposed two types of techniques for forming the core and the clad without eliminating the uncured photocurable resin liquid. The first technique is to cure only the photocurable resin liquid on the higher refractive index side with a longer wavelength relatively slowly and form an axial core containing more of the cured photocurable resin on the higher refractive index side. Technology. The second technique is to cure only the photocurable resin liquid having a longer wavelength and a lower refractive index side relatively quickly, and by diffusing two kinds of photocurable resin liquids in the “liquid phase” of the outer periphery of the core. Finally, this is a technique for forming an axial core having a sheath-like clad containing a larger amount of a light-cured resin cured product on the low refractive index side. The first technique is also described in JP-A-2002-365459 and others. The second technique is described in JP 2004-1499579 A, JP 2004-151160 A, and others.

  The container piece is preferably one that can hold the clad, and preferably has good adhesion to the clad material to be used. When a photocurable resin liquid is used as the cladding material, it is easy to irradiate the curing light when a transparent resin is used. When the end of the optical fiber is connected to the container piece, it is preferable that a through hole is formed in one place of the container piece, and the entire optical fiber or only the core is inserted and fixed. In addition, any number of light introducing portions similar to the light introducing portions provided in the mold portion may be formed on the container piece.

  The mold part is provided with a structure for positioning the light emitting / receiving element or the like on the clad surface. In order to obtain a structure for fitting, the mold part is provided with irregularities corresponding to the irregularities for fitting such as light receiving and emitting elements. The mold part may use a light-shielding material if the light introduction part is a through-hole. Also, if the light introduction part is not a through-hole, the other part is not transparent if a transparent material is used for the part. Also good. In order to improve the mold separation from the clad, a device such as applying a release agent to the mold portion may be arbitrarily performed.

  An example of the mold part and the container piece will be described, and a “light introducing part” of the mold part, a predetermined structure to be formed on the cladding surface, and the shape of the mold part for that purpose will be described. FIG. 1A is a perspective view showing a container piece 10 and mold parts 21 and 22 according to an embodiment of the present invention, FIG. B is a perspective view when they are combined to form a housing M capable of holding a photocurable resin liquid, FIG. C is a perspective view showing an appearance of an optical module 1000 according to an embodiment of the present invention.

  FIG. As in A, in this example, the container piece 10 is assumed to have three left and right side walls 10a, a bottom 10b, and a back side wall 10c, which are in contact with three surfaces of a substantially rectangular parallelepiped. . Among these, the left side wall 10a is provided with a through hole 101, from which an optical fiber core is inserted from the outside. In addition, FIG. A and FIG. B shows a diagram in which the wavelength selective mirrors 31 and 32 are erected on the bottom 10b. The wavelength selective mirrors 31 and 32 are designed to have an arbitrary wavelength transmittance characteristic by a dielectric multilayer film.

  FIG. A mold part 21 is arranged on the right side of the A container piece 10 and a mold part 22 is arranged on the front side of the container piece 10. The mold part 21 and the mold part 22 are provided with recesses 211-1 and 211-2, recesses 221-1 and 221-2 and recesses 222-1 and 222-2 described in FIG. Light introducing portions 211, 221 and 222 described below are provided. The light introducing portions 211, 221 and 222 may be through holes, or at least the portions may be transparent.

  FIG. Like B, the container piece 10 and the mold parts 21 and 22 are combined to form the housing M. That is, the container piece 10 has a left side wall 10a, a bottom 10b, and a back side wall 10c, but does not have a right side wall and a front side wall. These roles are supplemented by the mold parts 21 and 22. In addition, when the light introduction parts 211, 221 and 222 are through holes, the holes are closed by inserting the core of the optical fiber in the same manner as the through hole 101. In this way, at least from the optical fiber and the light introducing portions 211, 221 and 222, which are filled with the first photo-curing resin liquid in such an amount that the core end of the optical fiber to be inserted into the through hole 101 is buried. If the curing wavelength light is introduced, a core is formed. Thereafter, the uncured first photocurable resin liquid is removed from the casing M, and the second photocurable resin liquid is filled into the casing M and photocured.

  Thereafter, when the mold parts 21 and 22 are removed, FIG. As shown in C, the optical module 1000 is obtained. In the optical module 1000, the clad 50c obtained by curing the second photocurable resin liquid is joined to the container piece 10, and the core end 411-f and the protrusions 511-1 and 511-2 are arranged on the right side surface. The core end 421-f and the protrusions 521-1 and 521-2, and the core end 422-f and the protrusions 522-1 and 522-2 are exposed. The optical fiber 100 is bonded to the left side, and light introduced from the end of the optical fiber (not shown) depends on the wavelength, the core end 411-f on the right side, the core end 421-f on the front side, The light is emitted from any one of 422-f. The projections 511-1, 511-2, 521-1, 521-2, 522-1 and 522-2 formed on the surface of the clad 50c and cured by the second photocurable resin liquid are connected to the optical system. It is a predetermined structure used for element positioning.

  FIG. 4 of the present application. Below A, FIG. As shown in FIG. 1A, a cross-sectional view of the clad 50c in which the second photocurable resin liquid is cured is shown as if FIG. Although only the projections 511-1, 511-2, 521-1, 521-2, 522-1 and 522-2 like C are described, the surface shape of the clad 50c is shown in FIG. It is not limited to protrusions such as C. For example, FIG. FIG. An annular convex portion 501 such as a cross-sectional view of C (a cross section taken along a dashed line in FIG. 2.B) may be used. In addition, FIG. FIG. The star-shaped convex part 502 which has a ridgeline like the front view of E may be sufficient. In addition, a known arbitrary shape can be adopted and may be different for each positioning structure. Moreover, the number is arbitrary 1 or more for every optical element connected.

  Next, the mold part will be described with reference to FIG. FIG. Like A, the type | mold part 21 has the recessed parts 211-1 and 211-2, and the shape respond | corresponds to the recessed parts 611-1 and 611-2 of the light emitting / receiving element 611. FIG. The sizes and the like of the concave portions 211-1 and 211-2 of the mold portion 21 are formed by them as shown in FIG. The projections 511-1 and 511-2 of A are formed to be appropriately larger or smaller for fitting into the recesses 611-1 and 611-2 of the light receiving and emitting element 611. The mold part 21 has a light introducing part 211 and coincides with the optical axis of the effective surface 611-0 of the light receiving and emitting element 611. That is, the positional relationship between the concave portions 211-1 and 211-2 of the mold portion 21 and the light introducing portion 211 corresponds to the positional relationship between the concave portions 611-1 and 611-2 of the light emitting / receiving element 611 and the effective surface 611-0. .

  FIG. The positional relationship between the concave portions 221-1 and 221-2 of the A mold portion 22 and the light introducing portion 221 corresponds to the positional relationship between the concave portions 621-1 and 621-2 of the light emitting and receiving element 621 and the effective surface 621-0. . Similarly, the concave portions 222-1 and 222-2 and the light introducing portion 222 of the mold portion 22 are formed as shown in FIG. This corresponds to the positional relationship between the concave portions 621-1 and 621-2 of the light receiving and emitting element 622 and the effective surface 621-0 omitted in A.

  Instead of the mold part 21, FIG. An embodiment using the B mold part 21 'will be described later. The mold portion 21 ′ has a concave surface 211 c in contact with the core of the light introducing portion 211 ′, and is used to form a lens-shaped convex portion on the core. FIG. The positional relationship between the concave portions 211'-1 and 211'-2 of the B mold portion 21 'and the light introducing portion 211' is shown in FIG. This corresponds to the positional relationship between the concave portions 611-1 and 611-2 of the A light emitting / receiving element 611 and the effective surface 611-0.

  The light introduction part 211 of the mold part 21 may be configured as follows. The same applies to the light introducing portions 221 and 222 of the mold portion 22. FIG. Like C, the mold part 21 is provided with a through hole 211-th, and the optical fiber 200 is inserted therein. FIG. In C, the case where all the left sides from the broken lines of the core 200-cr and the clad 200-cld of the optical fiber 200 are inserted into the through holes 211-th of the mold part 21 is shown. At this time, the left side portion of the core 200-cr of the optical fiber 200 from the broken line is a light introducing portion 211 provided in the mold portion 21 in each of the following drawings.

  FIG. Like D, the mold part 21 is provided with a through hole 211-th, and only the core 200-cr of the optical fiber 200 is inserted therein. At this time, the left side portion of the core 200-cr of the optical fiber 200 from the broken line is a light introducing portion 211 provided in the mold portion 21 in each of the following drawings.

  FIG. Like E, the mold part 21 is provided with a transparent part 21-trp, and the core 200-cr of the optical fiber 200 is coupled thereto. At this time, the transparent part 21-trp of the mold part 21 is the light introducing part 211 provided in the mold part 21 in the following drawings. The other part of the mold part 21 may be transparent or light-shielding.

  FIG. Like F, the transparent part 21-trp is provided in the side which contacts the photocurable resin liquid of the type | mold part 21, and the recessed part 21-v is provided in the outer side, The core 200-cr of the optical fiber 200 is inserted here. . At this time, the left part of the transparent part 21-trp of the mold part 21 and the broken line of the core 200-cr of the optical fiber 200 is the light introducing part 211 provided in the mold part 21 in the following drawings. The other part of the mold part 21 may be transparent or light-shielding.

  Thus, each light introduction part of mold part 21 and 22 can be constituted variously. As easily conceived, FIG. C to FIG. The “optical fiber 200” of F may be replaced with another optical waveguide. For example, through the desired lens or aperture, FIG. The transparent portion of E may be directly irradiated with laser light. In addition, the above configuration can be arbitrarily modified and combined.

  FIG. A to FIG. F is a cross-sectional view illustrating each process for explaining a method of manufacturing the optical module 1000 according to the present embodiment. FIG. As in A, a container piece 10 and mold parts 21 and 22 were prepared. The container piece 10 is shown in FIG. As shown also in A, it consists of transparent resin which has the left side wall 10a, the bottom part 10b, and the back side wall 10c which are three flat parts. In this example, the thickness was 1 mm made of acrylic. A through hole 101 is provided in the left side wall 10a. Wavelength selective mirrors 31 and 32 are erected on the bottom 10b. Further, as described in FIGS. 2 and 3, the mold part 21 and the mold part 22 are provided with the recesses 211-1, 211-2, 221-1, 221-2, 222-1 and 222-2, Introducing portions 211, 221 and 222 are provided. In order to simplify the drawing, it is assumed that an “optical fiber or the like” is already connected to the light introducing portions 211, 221 and 222.

  FIG. Like B, the core of the optical fiber 100 was inserted into the through hole 101 of the container piece 10. 2. connected to the optical fiber 100 and the three light introducing portions 211, 221 and 222; C-3. As the optical fiber 200 for F, an optical fiber made of quartz having a core diameter of 100 μm and a cladding diameter of 140 μm was used. Next, the case M formed by the container piece 10 and the mold parts 21 and 22 is filled with the first photocurable resin liquid 40. As the first photocurable resin liquid 40, an acrylic photocurable resin having a high refractive index and showing a radical polymerization reaction by light irradiation was used.

Next, from the end of the optical fiber 100 (not shown) and the light introducing portions 211, 221 and 222, the short wavelength laser (wavelength λ _W ) is transferred to the first photocurable resin liquid 40 held in the housing M. Introduced. As a short wavelength laser, an argon ion laser having a wavelength λ _W = 488 nm was emitted at an output intensity of 30 mW. As a result, the photocurable resin liquid 40 was cured by a photopolymerization reaction. At this time, the refractive index increased due to the curing of the photocurable resin liquid at the tip of the core, and the core continued to grow while confining the guided light by the self-focusing effect (self-forming optical waveguide). That is, FIG. As shown in C, the cores 401 and 411 are formed with the portion of the photocurable resin liquid 40 in contact with the core end of the optical fiber 100 inserted into the through-hole 101 and the light introducing portions 211, 221 and 222 as the growth start surface. , 421, 422 grew axially. The curing wavelength light reaches the wavelength-selective mirrors 31 and 32 that are translucent with respect to the wavelength λ _W , partly reflected and partly transmitted. That is, the cores 401, 411, 421, and 422 grew in an axial shape along the reflection path and the transmission path. At this time, the cores grown from different growth starting surfaces were drawn into each other and bonded together by self-alignment (optical solder effect). Due to this self-alignment effect, the cores are coupled to each other even when a slight angle deviation from the design occurs in the waveguide growth direction during the waveguide formation. After confirming that all the cores were bonded, the laser irradiation by the optical fiber was stopped. At this time, the diameter of the formed core was about 120 μm (FIG. 4.D). The transmission loss for the wavelength of 850 nm was about 0.8 dB / cm, and the loss in the wavelength selective mirrors 31 and 32 was about 0.5 dB / cm. Although the core growth slightly occurred in the upward direction in the drawing of the wavelength selective mirrors 31 and 32, FIG. Omitted below D.

  FIG. The uncured first photocurable resin liquid 40 of D is removed, and the second photocuring having a post-curing refractive index lower than the refractive index of the cores 401, 410, 411, 421, 422 (hereinafter simply referred to as the core 400). The resin liquid 50 was filled (FIG. 4.E). As the second photocurable resin liquid 50, an acrylic low refractive photocurable resin was used. This can be copolymerized with the remaining first photocurable resin liquid 40, and it is advantageous in that it does not require cleaning. At this time, since the core is fixed by the mold parts 21 and 22, and the wavelength selective mirrors 31 and 32, the core was not deformed or detached even when the photocurable resin liquid was replaced. Also, it was robust against mechanical vibrations.

Thereafter, the whole is irradiated with ultraviolet rays (wavelength λ _C <λ _W ) with an ultraviolet lamp to cure the low-refractive-index second photocurable resin liquid 50 inside the container piece 10 made of a transparent resin. Solidified. As a result, the clad 50c was formed around the core to form a step index type optical waveguide. At this time, the optical transmission loss with respect to the wavelength of 850 nm was about 0.5 dB / cm. In addition, as a resin for forming the clad, a method of curing by heat irradiation using a thermosetting resin having a low refractive index in addition to the above-described photocurable resin may be used.

  Thus, the mold parts 21 and 22 were removed, and the light receiving and emitting elements 611, 621, and 622 were assembled to obtain the optical module 1000. The light emitting / receiving elements 611, 621 and 622 are easily assembled by the protrusions 511-1, 511-2, 521-1, 521-2, 522-1 and 522-2 which are positioning structures formed on the surface of the clad 50c. It was attached. In addition, the effective surfaces 611-0, 621-0, and 622-0 of the light emitting / receiving elements 611, 621, and 622 were optically coupled to the cores 411, 421, and 422 with no optical axis deviation and with high accuracy. Further, there are no gaps between the effective surfaces 611-0, 621-0 and 622-0 of the light emitting / receiving elements 611, 621 and 622 and the cores 411, 421 and 422, and the light loss in this portion is also suppressed and high. Optical coupling efficiency was obtained. As described above, an optical module 1000 for three-wavelength multiplexing could be manufactured.

  The surfaces of the mold parts 21 and 22 may be made of a fluororesin surface to prevent adhesion between the mold parts 21 and 22 and the core 400 and the clad 50c and facilitate removal, or surface treatment with a mold release agent or the like. Good to have been. The mold parts 21 and 22 have a structure that can be separated into two parts so that they can be easily removed. Alternatively, for example, an adhesive such as an ultraviolet curable resin may be applied to the surface of the optical module 1000 to securely fix all the elements.

[Modification 1]
In the first embodiment, the core portion 400 of the optical waveguide is formed with the first photocurable resin liquid 40, and is replaced with the second photocurable resin liquid 50 and solidified to form the clad 50c. However, as described in the Applicant's application publication, using a mixed liquid in which two types of photocurable resin liquids having different curing start wavelengths and different refractive indexes after curing are used, the liquid replacement step May be omitted. In this case, FIG. After D, the clad 50c can be formed by immediately irradiating ultraviolet rays without replacing the photocurable resin liquid.

[Modification 2]
In the first embodiment, the optical fibers 200 are connected to the light introducing portions 211, 221 and 222 to grow the cores 411, 421 and 422. However, the optical fiber 200 may not be used. For example, an argon ion laser (100 mW) with a predetermined wavelength of light having a full width at half maximum of about 3 mm may be introduced from the light introducing portions 211, 221, and 222 of the mold portions 21 and 22. Thereby, an optical waveguide having a diameter of 2 to 3 mm is obtained. Alternatively, an equivalent result can be obtained even if the ultraviolet lamp is taken out with two or more apertures to obtain approximately parallel light (beam).

  FIG. This is an example in which cores 411c, 421c, and 422c having an optical shape such as a convex lens-shaped condensing optical system are formed by using a mold part 21 'indicated by B and a similar mold part 22'. FIG. As in A, the surfaces of the light introducing portions 211 ′, 221 ′, and 222 ′ of the mold portions 21 ′ and 22 ′ that are in contact with the first photocurable resin liquid 40 are concave surfaces 211 c, 221 c, and 222 c. Using this, FIG. When steps similar to those up to E are performed, cores 411c, 421c, and 422c having an optical shape such as a convex lens-shaped condensing optical system are formed (FIG. 5.B). When the mold parts 21 ′ and 22 ′ are removed and the light receiving / emitting elements 611, 621, and 622 are assembled, the light coupling efficiency of the cores 411c, 421c, 422c and the light receiving / emitting elements 611, 621, and 622 is increased by the condensing function of the convex lens. An enhanced optical module 2000 can be obtained (FIG. 5.C). In addition, it is good to fill the clearance gap which arises by providing a convex lens with arbitrary resin or fats and oils by design.

  In the above embodiment, the concave portions 611-1 and 611-2, 621-1 and 621-2, and 622-1 and 622-2 of the light receiving and emitting elements 611, 621, and 622 are formed in the shape of the surface of the cladding 50c itself. Although the projections 511-1, 511-2, 521-1, 521-2, 522-1, and 522-2 are shown fitted together, the projections and the like are made of a material different from that of the clad 50c, for example, pre-shaped. A metal pin may be used. This is shown in FIG. Metal pins 711-1, 711-2, 721-1, 721-2, 722-1, 722-2 are concave portions 211-1, 211-2, 221-1, 221-2, 222 of the mold parts 21 and 22. -1 and 222-2 (FIG. 6.A). Thereafter, FIG. When the same steps as those up to E are performed, FIG. In E, the protrusions 511-1, 511-2, 521-1, 521-2, 522-1, 522-2 are metal pins 711-1, 711-2, 721-1, 721-2, It becomes the state which became the exposed part of 722-1 and 722-2 (FIG. 6.B). The foot portions of the metal pins 711-1, 711-2, 721-1, 721-2, 722-1 and 722-2 are preferably key-shaped so as to be buried in the clad 50c and not easily pulled out. Even if the light receiving and emitting elements 611, 621, and 622 are fitted by such metal pins 711-1, 711-2, 721-1, 721-2, 722-1, and 722-2, the light is emitted in the same manner as in the first embodiment. An optical module 3000 having a small coupling loss can be easily obtained.

(Other variations)
The above embodiment is an example in which an optical receiving module for optical wavelength multiplexing (three-wavelength multiplexing one-way receiving device) is assumed, but the present invention is not limited to the optical receiving module. For example, the present invention can be applied to a two-wire bidirectional communication device and a two-wavelength multiplex single-wire bidirectional communication device.

The perspective view which shows the jig | tool used for the process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. The figure which shows the example of the positioning structure formed in the surface of the clad | crud 50c. Sectional drawing which shows the specific example of the shape of the mold parts 21 and 22, and the light introduction part 211,221,222. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows 1 process of the manufacturing method of the optical module 1000 which concerns on the specific 1st Example of this invention. Sectional drawing which shows the process of the manufacturing method of the optical module 2000 which concerns on the specific 2nd Example of this invention. Sectional drawing which shows the process of the manufacturing method of the optical module 3000 which concerns on the specific 3rd Example of this invention.

Explanation of symbols

10: container piece 100: optical fiber 21, 22: mold part 211, 221, 222: light introducing part 211-1, 211-2, 221-1, 221-2, 222-1, 222-2: concave part 31, 32: Wavelength selective mirror 401, 410, 411, 421, 422: Portion of core 400 50c: Cladding 511-1, 511-2, 521-1, 521-2, 522-1, 522-2: Protrusion 611, 621, 622: light emitting / receiving elements 611-0, 621-0, 622-0: effective surface 611-1, 611-2, 621-1, 621-2, 622-1, 622-2: concave portion

Claims (12)

An optical waveguide comprising a shaft-shaped core obtained by self-condensing a photocurable resin liquid, and a clad covering the core;
In a method for manufacturing an optical module having one or more optical elements,
A mold part for forming a predetermined structure for positioning on the clad for attaching the optical element;
By combining with the mold part, using a container piece that forms a housing capable of holding the photocurable resin liquid,
The photocurable resin liquid is held in the casing obtained by combining the mold part and the container piece, and is introduced from two or more places including at least a light introducing part positioned by the mold part A step of curing with light of the wavelength to form the shaft-shaped core;
Forming a clad having a predetermined structure for positioning using the mold part;
Removing the mold part from the optical waveguide;
Attaching at least one of the optical elements using the predetermined structure for positioning formed in the clad,
A method of manufacturing an optical module, characterized in that the optical axis of the optical element coincides with the optical axis of the core end formed by the curing wavelength light introduced from the light introducing part of the mold part. The method of manufacturing an optical module according to claim 1, wherein the optical element is a light emitting element, a light receiving element, or an optical waveguide and a connection structure provided at an end thereof. The optical module has one or more branches, and has a wavelength selective mirror at each branch point,
The wavelength selective mirror has a transmittance and a reflectance of 20% or more with respect to the curing wavelength light,
3. The method of manufacturing an optical module according to claim 1, wherein the photocurable resin liquid is introduced after the one or more wavelength selective mirrors are fixed to the container piece. Fixing at least one optical fiber to the container piece;
4. The method of manufacturing an optical module according to claim 1, wherein the curing wavelength light is introduced into the photocurable resin liquid through the optical fiber. The predetermined positioning structure for attaching the optical element is formed by a concave portion and / or a convex portion formed on the surface of the clad by transferring the convex portion and / or the concave portion of the mold portion. The manufacturing method of the optical module of any one of Claim 1 thru | or 4. 6. The optical module according to claim 5, wherein the concave portion and / or convex portion formed on the surface of the clad is fitted with the corresponding convex portion and / or concave portion on the surface of the optical element. Method. 6. The method of manufacturing an optical module according to claim 5, wherein the concave portion and / or the convex portion formed on the surface of the clad are fitted with a shape of the outer periphery of the optical element. The predetermined structure for positioning for mounting the optical element is a structure that is held by the mold part before formation of the clad and is fixed to the clad after formation of the clad. The manufacturing method of the optical module of any one of Claim 1 thru | or 4. The method of manufacturing an optical module according to claim 8, wherein the shape of the exposed portion of the structure from the clad is fitted with a corresponding convex portion and / or concave portion of the surface of the optical element. The method of manufacturing an optical module according to claim 8, wherein a shape of an exposed portion of the structure body from the clad is matched with a shape of an outer periphery of the optical element. The method of manufacturing an optical module according to claim 1, wherein the mold part includes a plurality of mold pieces and is separable. 2. The concave portion for forming a convex lens at the end of the core is formed in a portion of the mold portion that is in contact with the end of the core. The method for manufacturing an optical module according to claim 11.

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