JP2008089879A - Optical coupler, optical connector, and receptacle type optical transmission module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical coupler capable of highly accurately aligning a lens and an optical waveguide with a simple configuration. <P>SOLUTION: The optical coupler 1A is composed of: a lens array 4A having a plurality of lenses 41A; an optical waveguide 3A in which a plurality of cores 32 for propagating light are provided and in which core end faces 34a for emitting light are arranged in accordance with the lenses 41A; an engaging projection 40A which is structured by forming a projection in the lens array 4A; a tapered aligning groove 30A which is structured by forming a recess for fitting the engaging projection 40A in the optical waveguide 3A and which aligns optical axes in the lenses 41A and the core end faces 34a. The engaging projection 40A and the tapered aligning groove 30A are in contact with each other in a tapered shape in which one end narrows down along the optical axis direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical coupler, an optical connector, and a receptacle-type optical transmission module in which an optical waveguide is coupled to a lens member. Specifically, by aligning the lens member and the optical waveguide by fitting the positioning part having a tapered shape in the optical axis direction and the fitting part, the manufacturing accuracy error between the positioning part and the fitting protrusion is reduced. Can be converted into a positional deviation in the optical axis direction.

  There has been proposed an optical module that can automatically perform alignment without performing active alignment that performs alignment by actually emitting light from a light emitting element or the like when mounting an optical component (for example, Patent Documents). 1).

  For example, a technology has been proposed in which an optical waveguide as an optical component is mounted on a substrate, a stepped portion for alignment is formed on the substrate and the housing, and automatic alignment is performed by pressing the stepped portions together. Yes.

  In addition to mounting the light emitting element and the light receiving element as optical components on the substrate, forming a stepped portion for alignment between the substrate and the housing, enabling automatic alignment by pressing the stepped portions, and A technique in which a microlens is mounted on a housing has been proposed.

Japanese Patent Laid-Open No. 2001-324631 (FIGS. 1, 2, and 8)

  The conventional optical module has a configuration in which an optical component such as a microlens and an optical waveguide is coupled via a housing. For this reason, double misalignment errors of the accuracy of attaching the microlens to the housing and the accuracy of aligning the housing and the optical waveguide are accumulated, making it difficult to position with high accuracy. In addition, since two mounting steps are required, the number of man-hours increases, which is disadvantageous in terms of manufacturing costs.

  Further, a step for aligning the housing and the optical waveguide is formed by anisotropic etching of the silicon substrate on which the optical waveguide is mounted, and the alignment step is aligned with the optical axis. It has a taper shape in the vertical direction.

  In this way, if alignment is attempted with a stepped portion having a taper shape in a direction perpendicular to the optical axis, the optical axis has a severe positional deviation tolerance due to errors in the manufacturing accuracy of the width of the step and the width of the protrusion fitted therein. Positional deviation occurs in the vertical direction, and high-precision positioning is difficult.

  The present invention has been made to solve such a problem, and provides an optical coupler, an optical connector, and a receptacle-type optical transmission module capable of aligning a lens and an optical waveguide with high accuracy with a simple configuration. Objective.

  In order to solve the above-described problems, an optical coupler of the present invention includes a lens member having at least one lens and at least one core through which light propagates, and a core from which light is emitted or incident. The core end face of the optical waveguide is arranged in accordance with the lens, and the optical waveguide is joined to the lens member by optically coupling the core to the lens, and the convex portion is formed at the joint portion of the lens member and the optical waveguide. And a positioning portion configured to align the optical axis of the lens and the core end face of the core. The joining portion and the positioning portion are in contact with each other with at least a portion having a tapered shape in which one side becomes narrower along the optical axis direction.

  The optical connector of the present invention has a lens member having at least one lens and at least one core through which light is propagated, and the core end surface of the core from which light is emitted or incident is arranged according to the lens. An optical waveguide that is optically coupled to the lens and joined to the lens member, an optical fiber that is coupled to the lens member via the core of the optical waveguide, and a convex portion at the joint between the lens member and the optical waveguide. And a concave portion in which the fitting portion is fitted at the joint portion between the lens member and the optical waveguide, and the optical axis is aligned on the core end surfaces of the lens and the core. The fitting portion and the positioning portion are in contact with each other with a tapered shape in which one of the fitting portion and the positioning portion becomes thinner along the optical axis direction.

  The receptacle-type optical transmission module of the present invention has a lens member having at least one lens and at least one core through which light propagates, and the core end surface of the core from which light is emitted or incident is the lens. An optical waveguide that is disposed together and optically couples the core with the lens and is joined to the lens member; and a light-emitting device and / or a light-receiving device that are coupled to the lens member via the core of the optical waveguide; Both the light receiving device, a fitting portion formed by forming a convex portion at the joint portion between the lens member and the optical waveguide, and a concave portion where the fitting portion is fitted at the joint portion between the lens member and the optical waveguide are formed. And a positioning part that aligns the optical axis at the core end surface of the lens and the core, and at least a part of the fitting part and the positioning part is thin along the optical axis direction. Wherein the contact has a path shape.

  In the optical coupler, the optical connector, and the receptacle type optical transmission module of the present invention, the fitting portion is fitted to the positioning portion, and the lens member and the optical waveguide are joined. Even if there is a manufacturing accuracy error between the positioning part and the fitting part due to the contact between the positioning part having a tapered shape in the optical axis direction and the fitting part, dimensional variation due to the manufacturing precision error has a large tolerance for the position accuracy. It is converted into a positional shift in the optical axis direction, and the core and the lens are aligned.

  According to the present invention, since the lens member and the optical waveguide are joined by fitting the positioning portion having a tapered shape and the fitting portion along the optical axis direction, the manufacturing accuracy error between the positioning portion and the fitting portion is caused. Can be converted into a positional shift in the optical axis direction. Thereby, it is possible to reduce excess loss of optical coupling between the lens of the lens member and the core of the optical waveguide.

  Embodiments of an optical coupler, an optical connector, and a receptacle type optical transmission module according to the present invention will be described below with reference to the drawings.

<Configuration Example of Optical Coupler of First Embodiment>
1 and 2 are configuration diagrams showing an example of the optical coupler of the first embodiment. FIG. 1A is a plan view of the optical coupler 1A of the first embodiment, and FIG. b) is a side sectional view of the optical coupler 1A, and FIG. 2 is an exploded perspective view of the optical coupler 1A.

  The optical coupler 1A of the first embodiment includes a laser array 2A, an optical waveguide 3A, and a lens array 4A, and the laser array 2A and the lens array 4A are optically coupled via the optical waveguide 3A.

  The optical coupler 1A has a tapered positioning groove by aligning the optical waveguide 3A and the lens array 4A by fitting the fitting protrusion 40A into the tapered positioning groove 30A having a tapered shape in the optical axis direction. The manufacturing accuracy error between 30A and the fitting projection 40A is converted into a positional deviation in the optical axis direction.

  Details of the configuration of the optical coupler 1A will be described below. The laser array 2A is an example of a light-emitting device, and a plurality of light-emitting elements are arranged in a line. In this example, the laser array 2A is an 8-channel laser array in which eight light-emitting elements are arranged at equal intervals at a predetermined pitch. The light emitting element is a surface emitting semiconductor laser (VCSEL), which converts an input electric signal into an optical signal and emits it in a direction perpendicular to the substrate.

  In the optical waveguide 3A, the waveguide sheet 31A is mounted on the mounting substrate 5A. The mounting substrate 5A includes a mounting portion 50 on which the laser array 2A is mounted, a wiring pattern (not shown) that is electrically connected to the laser array 2A, and the like. The mounting substrate 5A is made of, for example, silicon (Si), and a recess having a rectangular opening is manufactured by etching or the like according to the shape of the laser array 2A, and the laser array 2A is placed on the surface of the mounting substrate 5A. Part 50 is formed.

  The waveguide sheet 31A is an embedded waveguide having at least one or more cores 32 through which light propagates, an underclad 33a and an overclad 33b covering the cores 32, and the laser array 2A is mounted on the mounting unit 50. It is mounted on the surface of the mounted substrate 5A by adhesive fixing or the like.

  The waveguide sheet 31A is made of, for example, a polymer waveguide material having photosensitivity, and is configured such that the refractive index of the core 32 is slightly larger than the refractive indexes of the underclad 33a and the overclad 33b. The combined light is confined in the core 32 and propagated.

  In the waveguide sheet 31A, eight cores 32 arranged in parallel at equal intervals with the pitch of the light emitting elements of the laser array 2A extend linearly from one end side to the other end side of the waveguide sheet 31A in this example, A vertical end face 34 is provided at one end where each core 32 intersects. The vertical end surface 34 is configured by a surface perpendicular to the plane of the waveguide sheet 31A, and each core 32 is exposed to form a core end surface 34a from which light is emitted or incident.

  The waveguide sheet 31 </ b> A includes an inclined end surface 35 at the other end where each core 32 intersects. The inclined end surface 35 has an inclination of about 45 degrees with respect to the plane of the waveguide sheet 31A, and the end surface of each core 32 is exposed to form a reflecting surface 35a.

  The reflection surface 35 a causes the light incident from the lower surface of the waveguide sheet 31 </ b> A to be totally reflected at the boundary with the air and is incident on the core 32. Further, the reflection surface 35a totally reflects the light propagating through the core 32 at the boundary with air, and emits the light from the lower surface of the waveguide sheet 31A.

  In this example, when the waveguide sheet 31A is aligned and mounted on the surface of the mounting substrate 5A on which the laser array 2A is mounted in alignment with the mounting portion 50, each light emission of the laser array 2A is achieved. The reflection surface 35a of each core 32 of the waveguide sheet 31A is aligned and positioned directly above the element.

  The lens array 4A is an example of a lens member, and includes a lens forming portion 42A in which a plurality of lenses 41A are integrally formed, and a mounting portion 43A on which the optical waveguide 3A is mounted is formed on the back surface of the lens forming portion 42A.

  The lens array 4A is made of, for example, a resin material that has a refractive index substantially equal to the core 32 of the waveguide sheet 31A and is transparent to light of a desired wavelength, and is integrally formed by molding using a mold or the like. Molded.

  Each lens 41A is configured by arranging convex lenses for condensing or collimating (collimating) light in a line at a predetermined pitch on the front surface of the lens forming portion 42A. In this example, each lens 8A is 8 in accordance with the laser array 2A. The individual lenses 41A are arranged at equal intervals at the same pitch as the light emitting elements.

  The mounting portion 43A is configured by forming a space in which the optical waveguide 3A enters in the back side of the position where the lens 41A of the lens forming portion 42A is formed.

  Next, a configuration in which the optical waveguide 3A and the lens array 4A are aligned so that the core 32 and the lens 41A are optically coupled when the optical waveguide 3A and the lens array 4A are joined will be described.

  The optical waveguide 3A includes a tapered positioning groove 30A on the vertical end surface 34 of the waveguide sheet 31A. The tapered positioning groove 30 </ b> A is an example of a positioning portion, and is configured by forming a groove portion that opens the vertical end surface 34 and the upper surface of the waveguide sheet 31 </ b> A at one place on both the left and right sides along the parallel direction of the core 32.

  The tapered positioning groove 30A has a tapered shape in which the groove width gradually decreases from the opening facing the vertical end surface 34 of the waveguide sheet 31A along the Y direction that is the optical axis direction of the core end surface 34a of the core 32. The positioning surface 36A is provided.

  The positioning surface 36A is configured by opposing side surfaces of the tapered positioning groove 30A facing the X direction (lateral direction) which is one direction perpendicular to the optical axis on the core end surface 34a of the core 32, and is positioned facing the X direction. The distance between the surfaces 36A gradually decreases along the Y direction, which is the optical axis direction. Further, the positioning surface 36A is formed to be a substantially vertical surface along the Z direction in the Z direction (height direction) which is another direction perpendicular to the optical axis. Thus, the tapered positioning groove 30A has a V shape on the plane of the waveguide sheet 31A.

  The tapered positioning groove 30A is manufactured, for example, by forming a groove portion in the overcladding forming material on the undercladding 33a in the formation process of the overcladding 33b constituting the waveguide sheet 31A.

  Alternatively, the taper positioning groove 30A is made of a core forming material on the under clad 33a in the process of forming the core 32 constituting the waveguide sheet 31A, and the taper positioning groove 30A is over the taper positioning groove 30A in the process of forming the over clad 33b. It is exposed from the clad 33b. Here, in this example, the tapered positioning groove 30A is described as an example manufactured by the process of forming the over clad 33b.

  The optical waveguide 3A includes a height positioning groove 37A on the upper surface of the waveguide sheet 31A. The height positioning groove 37 </ b> A is an example of a height positioning portion, and a groove portion having an opening on the upper surface of the waveguide sheet 31 </ b> A and having a bottom surface as a flat surface is formed at each of the left and right sides along the parallel direction of the core 32. Configured.

  The height positioning groove 37A is manufactured by, for example, the formation process of the over clad 33b constituting the waveguide sheet 31A, and the upper surface of the under cladding 33a is exposed on the bottom surface of the height positioning groove 37A.

  The lens array 4A includes a fitting protrusion 40A on the mounting portion 43A on the back surface of the lens forming portion 42A. The fitting protrusion 40A is an example of a fitting portion, and is arranged at one place on both the left and right sides along the parallel direction of the lens 41A according to the arrangement of the tapered positioning groove 30A formed in the waveguide sheet 31A of the optical waveguide 3A. It is formed.

  The fitting protrusion 40A includes an abutting surface 44A that protrudes in the Y direction, which is the optical axis direction of the lens 41A, and contacts the positioning surface 36A of the tapered positioning groove 30A of the optical waveguide 3A. The abutting surface 44A has a width in the X direction, which is one direction perpendicular to the optical axis of the lens 41A, along the Y direction, which is the optical axis direction, in accordance with the shape of the tapered positioning groove 30A of the optical waveguide 3A. It has a tapered shape that gradually narrows. The abutting surface 44A is formed so as to be a substantially vertical surface along the Z direction in the Z direction, which is another direction perpendicular to the optical axis.

  The tapered positioning groove 30A of the optical waveguide 3A and the fitting projection 40A of the lens array 4A are fitted into the tapered positioning groove 30A and the fitting projection 40A when the optical waveguide 3A and the lens array 4A are joined. The positioning surface 36A of the positioning groove 30A and the abutting surface 44A of the fitting projection 40A are in contact with each other.

  The tapered positioning groove 30A of the optical waveguide 3A and the fitting projection 40A of the lens array 4A contact the optical axis of the core end surface 34a of the core 32 of the optical waveguide 3A and the lens when the positioning surface 36A and the abutting surface 44A contact each other. The optical axis of the lens 41A of the array 4A is parallel to the optical axis, and the optical axis is aligned in the X direction, which is one direction perpendicular to the optical axis.

  The lens array 4A includes a protrusion 45A for raising the height on the lower surface of the mounting portion 43A. The height protrusion 45A is an example of a height fitting portion. Both the left and right sides along the parallel direction of the lens 41A are aligned with the arrangement of the height positioning grooves 37A formed in the waveguide sheet 31A of the optical waveguide 3A. Are formed one by one.

  The height protrusion 45A has a shape that matches the height positioning groove 37A of the optical waveguide 3A, and protrudes in the Z direction, which is another direction perpendicular to the optical axis of the lens 41A.

  The height positioning groove 37A of the optical waveguide 3A and the height projection 45A of the lens array 4A are inserted into the height positioning groove 37A when the optical waveguide 3A and the lens array 4A are joined. In addition, the bottom surface of the height projection 45A is in contact with the bottom surface of the height positioning groove 37A.

  When the bottom surface of the height positioning groove 37A of the optical waveguide 3A and the height projection 45A of the lens array 4A are in contact with each other, the optical axis of the core end surface 34a of the core 32 of the optical waveguide 3A and the lens array 4A The optical axis of the lens 41A is parallel to the optical axis, and the optical axis is aligned in the Z direction, which is another direction perpendicular to the optical axis.

  Further, the size in the XY direction of the height projection 45A of the lens array 4A is configured to be slightly smaller than the height positioning groove 37A of the optical waveguide 3A.

  In this example, the fitting projection 40A and the height projection 45A of the lens array 4A are configured with the same height in the Z direction, and the tapered positioning groove 30A and the height positioning groove 37A of the optical waveguide 3A are: It is configured with the same depth in the Z direction.

  That is, when the optical waveguide 3A and the lens array 4A are joined, the bottom surface of the fitting projection 40A of the lens array 4A fitted in the tapered positioning groove 30A of the optical waveguide 3A is the bottom surface of the tapered positioning groove 30A. It contacts the upper surface of the underclad 32a. Further, the bottom surface of the height projection 45A of the lens array 4A inserted into the height positioning groove 37A of the optical waveguide 3A is in contact with the upper surface of the under cladding 32a that is the bottom surface of the height positioning groove 37A.

  As a result, the tapered positioning groove 30A of the optical waveguide 3A and the fitting projection 40A of the lens array 4A are positioned between the optical axis of the core end surface 34a of the core 32 of the optical waveguide 3A and the optical axis of the lens 41A of the lens array 4A. It has a function of performing alignment in both the X direction and the Z direction perpendicular to the optical axis.

  The optical waveguide 3A and the lens array 4A are fixed with, for example, an ultraviolet curable adhesive. This adhesive has a refractive index substantially equal to that of the core 32 of the waveguide sheet 31A and the lens array 4A and is transparent to light having a desired wavelength. Then, the adhesive is filled between the vertical end surface 34 of the waveguide sheet 31A and the back surface of the lens forming portion 42A of the lens array 4A so that the reflection at the core end surface 34a or the like does not occur, and the coupling is performed. This prevents an increase in loss.

<Example of manufacturing process of waveguide sheet of this embodiment>
3 and 4 are process diagrams showing an example of a method for manufacturing a waveguide sheet in which the tapered positioning groove is formed of an over clad layer. Next, the core 32, the under clad 33a and the over clad 33b are all photosensitive. An example of a manufacturing process of the waveguide sheet 31A manufactured by a polymer material and manufacturing the tapered positioning groove 30A by the formation process of the over clad 33b will be described. Here, FIG. 3 shows an outline of the manufacturing process of the site where the tapered positioning groove 30A is formed, and FIG. 4 shows the outline of the manufacturing process of the site where the height positioning groove 37A is formed.

  First, as shown in FIGS. 3A and 4A, an ultraviolet curable resin is applied as a photosensitive polymer material on a silicon substrate 100 in a wafer state by spin coating or the like. After forming a thin film constituting the clad 33a and performing pre-baking, the thin film is cured by irradiating ultraviolet rays (UV) to form an under clad 33a.

  Next, as shown in FIGS. 3B and 4B, an ultraviolet curable resin having a higher refractive index than that of the underclad 33a is formed on the underclad 33a formed on the silicon substrate 100 by spin coating or the like. The thin film 110 constituting the core 32 is formed by coating. Then, the portion where the core 32 is formed is cured by irradiating ultraviolet rays through the mask 101 in which the pattern of the core 32 is formed by a photolithography process, and the portions other than the portion where the core 32 is formed are removed by solution development. As shown in FIGS. 3C and 4C, the core 32 is formed in a predetermined pattern. In this example, as shown in FIGS. 1 and 2, an 8-channel linear core 32 is formed.

  Next, as shown in FIGS. 3D and 4D, the same ultraviolet curable resin as the undercladding 33a is formed on the undercladding 33a formed on the silicon substrate 100 and the core 32 having a predetermined pattern. The thin film 111 constituting the over clad 33b is formed by spin coating or the like, and prebaking is performed. Next, the tapered positioning groove 30A and the height positioning groove 37A are formed by irradiating ultraviolet rays through the mask 102 in which the pattern of the tapered positioning groove 30A and the height positioning groove 37A is formed by a photolithography process. Cure everything except the part. Then, the portions where the tapered positioning groove 30A and the height positioning groove 37A are formed are removed by solution development, and as shown in FIGS. 3E and 4E, the tapered positioning groove 30A and the height positioning groove 30A are formed. Overclad 33b in which 37A is formed is formed.

  Here, in this example, the resin material constituting the over clad 33b is the same material as the polymer material constituting the under clad 33a. However, if the refractive index is substantially equal to that of the under clad 33a, another material is used. It is also possible to use it.

  In this example, a pattern such as the core 32 is formed by a photolithography process using an ultraviolet curable resin. However, a patterning method using a thermosetting resin and a metal mask is used. There is also a method of forming a mask by transferring a pattern by RIE.

  As described above, the waveguide sheet 31A in which the tapered positioning groove 30A and the height positioning groove 37A are manufactured has an angle of 45 degrees with respect to a portion serving as the side on which the inclined end surface 35 described with reference to FIGS. The inclined end surface 35 and the reflective surface 35a are formed by dicing using a dicing plate having Further, the other side portion is diced using a dicing plate having an angle of 90 degrees to cut out the waveguide sheet 31A having a predetermined shape.

  Then, the waveguide sheet 31A is peeled from the silicon substrate 100 to complete the waveguide sheet 31A.

  As shown in FIGS. 1 and 2, the waveguide sheet 31A manufactured by the above manufacturing process is used as a light emitting point of each light emitting element of the laser array 2A mounted in alignment with the mounting portion 50 of the mounting substrate 5A. The reflective surface 35a of each core 32 is aligned using a marker or the like, and is adhered and fixed to the surface of the mounting substrate 5A, thereby forming the optical waveguide 3A.

<Example of bonding operation between optical waveguide and lens array>
Next, an operation of joining the lens array 4A to the optical waveguide 3A in which the waveguide sheet 31A is mounted on the mounting substrate 5A as described above will be described.

  The optical waveguide 3A and the lens array 4A are formed by fitting the fitting protrusion 40A of the lens array 4A into the tapered positioning groove 30A of the waveguide sheet 31A from the Y direction that is the optical axis direction, thereby positioning the tapered positioning groove 30A. The center position in the X direction, which is one direction perpendicular to the optical axis, is matched by the shape of the abutting surface 44A of 36A and the fitting projection 40A.

  FIG. 5 is an operation explanatory view showing the effect of alignment by the tapered positioning groove and the fitting protrusion.

  As described above, the tapered positioning groove 30A of the waveguide sheet 31A is manufactured by patterning by a photolithography process in the formation process of the over clad 33b in this example.

  In the photolithography process, the pattern width varies somewhat due to variations in exposure conditions and development conditions. However, the center position of the groove is determined by the photomask manufacturing accuracy, and by applying the semiconductor manufacturing process, the amount of variation in the center position of the groove is small.

  For example, even if the groove width W1 and the groove width W2 vary as in the tapered positioning groove 30A (1) indicated by the solid line and the tapered positioning groove 30A (2) indicated by the broken line in FIG. The center position O in the X direction, which is one perpendicular direction, in this example, the apex position of the tapered shape substantially matches regardless of the groove width.

  Accordingly, when the tapered positioning groove 30A having a tapered shape in which the groove width is gradually narrowed in the Y direction that is the optical axis direction is used, there is a variation in the groove width W1 and the groove width W2, as shown in FIG. However, when the fitting projection 40A of the lens array 4A is pressed, the position of the fitting projection 40A in the X direction is aligned to a fixed position regardless of the variation in the groove width of the tapered positioning groove 30A.

  Then, the variation w (= W2−W1) in the groove width of the tapered positioning groove 30A is converted into a positional deviation La of the fitting protrusion 40A in the Y direction, which is the optical axis direction, as shown by a solid line and a broken line in FIG. Will be.

  Considering the tolerance of the positional deviation between the optical waveguide 3A and the lens array 4A, the tolerance is not so large for the positional deviation in the direction perpendicular to the optical axis, but the positional deviation tolerance in the optical axis direction is very large. .

  Thereby, in the alignment structure of the optical waveguide 3A and the lens array 4A using the tapered positioning groove 30A having a tapered shape in the optical axis direction and the fitting protrusion 40A, the variation in the groove width of the tapered positioning groove 30A is as follows. It is converted into a positional shift of the fitting protrusion 40A in the Y direction which is the optical axis direction, and the core end surface 34a of the core 32 of the optical waveguide 3A and the lens 41A of the lens array 4A are in one direction perpendicular to the optical axis. The direction position is adjusted.

  Therefore, even if the groove width of the tapered positioning groove 30A varies, the optical deterioration can be suppressed and the cores of the optical waveguide 3A and the lenses 41A of the lens array 4A can be coupled to reduce coupling loss. Can do.

  The position in the Z direction, which is another direction perpendicular to the optical axis of the optical waveguide 3A and the lens array 4A, is the height formed in the lens array 4A on the bottom surface of the height positioning groove 37A formed in the optical waveguide 3A. The bottom surface of the protrusion 45A is pressed and the bottom surface of the fitting groove 40A is pressed against the bottom surface of the tapered positioning groove 30A.

  The tapered positioning groove 30A and the height positioning groove 37A are formed by patterning a thin film that forms the over clad 33b in the process of forming the over clad 33b of the waveguide sheet 31A. Exposed.

  In the formation process of the core 32, a thin film to be a core layer is formed on the upper surface of the underclad 33a. Therefore, the positional accuracy from the upper surface of the underclad 33a to the center in the height direction of the core 32 is determined by the thickness of the core layer. . Since the core layer is manufactured by spin coating, the film thickness accuracy is very high.

  Thus, the optical waveguide 3A and the lens array 4A press the bottom surface of the height projection 45A against the upper surface of the under cladding 33a that is the bottom surface of the height positioning groove 37A, and the under surface that is the bottom surface of the tapered positioning groove 30A. By adopting a positioning structure in which the bottom surface of the fitting projection 40A is pressed against the top surface of the clad 33a, the core end surface 34a of the core 32 and the lens 41A can be aligned with each other in the Z direction, which is another direction perpendicular to the optical axis. Can be done.

  The size of the height positioning groove 37A of the optical waveguide 3A in the XY direction is slightly larger than the height protrusion 45A of the lens array 4A, and the height protrusion 45A is formed in the height positioning groove. The lens array 4A can be moved in the XY direction along the plane of the waveguide sheet 31A of the optical waveguide 3A while being inserted into 37A.

  As a result, the fitting protrusion 40A of the lens array 4A is slid from the wide groove width portion of the tapered positioning groove 30A of the optical waveguide 3A, and the fitting protrusion 40A protrudes onto the positioning surface 36A of the tapered positioning groove 30A. Positioning can be performed by pressing the contact surface 44A. Therefore, the fitting process of each protrusion of the lens array 4A and each groove of the optical waveguide 3A can be performed with a simple operation.

  As described above, the bottom surface of the height projection 45A is pressed against the bottom surface of the height positioning groove 37A, the bottom surface of the fitting projection 40A is pressed against the bottom surface of the tapered positioning groove 30A, and the tapered positioning groove is further pressed. The abutting surface 44A of the fitting projection 40A is pressed against the positioning surface 36A of 30A, and the aligned optical waveguide 3A and lens array 4A are fixed with an ultraviolet curable adhesive.

  That is, the optical waveguide 3A and the lens array 4A are aligned, between the vertical end surface 34 of the waveguide sheet 31A and the rear surface of the lens forming portion 42A of the lens array 4A, and between the upper surface of the waveguide sheet 31A and the lens array 4A. An ultraviolet curable adhesive is filled between the lower surface of the mounting portion 43A and the adhesive is cured by irradiating with ultraviolet rays.

  Thus, the optical waveguide 3A and the lens array 4A are bonded and fixed while maintaining the accuracy of alignment between the protrusions and the grooves.

  Through the above steps, the light emitted from the laser array 2A is accurately guided to the lens array 4A via the optical waveguide 3A, and the light emitted from the laser array 2A is emitted in a predetermined manner such as collimation or condensing. The transmission module can be easily manufactured.

  The lens array 4A described above is manufactured by molding using a resin material having a refractive index substantially equal to the refractive index of the core 32 of the waveguide sheet 31A. Accordingly, the lens 41A, the fitting protrusion 40A, and the height raising protrusion 45A can be integrally molded, which is extremely excellent in mass productivity.

  Here, in the above-described embodiment, the laser array is used as the light emitting device. However, it is obvious that the photodiode can be applied to the optical receiving module by using the photodiode (PD) as the light receiving device. By using both, it can be applied to an optical transceiver module.

  Further, the same alignment effect can be obtained when the taper-shaped positioning grooves 30A and the fitting protrusions 40A have opposite taper directions. Furthermore, the shape of the fitting protrusion 40A is not limited to the triangular shape, but the same alignment effect can be obtained even when the fitting protrusion 40A is pressed against the positioning surface 36A of the tapered positioning groove 30A, for example.

  Further, if the tapered positioning groove 30A is manufactured by the process of forming the core 32, the positional accuracy of the tapered positioning groove 30A can be matched with the positional accuracy of the core 32. Further, the bottom surface of the height positioning groove 37A may be formed on the top surface of the core layer.

<Configuration Example of Optical Coupler of Second Embodiment>
FIG. 6 is a configuration diagram illustrating an example of the optical coupler according to the second embodiment. FIG. 6A is a plan view of the optical coupler 1B according to the second embodiment, and FIG. It is a sectional side view of the optical coupler 1B.

  The optical coupler 1B of the second embodiment includes a fiber array 6, an optical waveguide 3B, and a lens array 4B, and the fiber array 6 and the lens array 4B are optically coupled via the optical waveguide 3B.

  The fiber array 6 is integrally covered with a plurality of optical fibers 60 arranged in parallel at equal intervals. Each optical fiber 60 is, for example, a multimode optical fiber, and an end portion of the fiber array 6 coupled to the optical coupler 1B or the like exposes each optical fiber 60 one by one.

  In the optical waveguide 3B, a waveguide sheet 31B is mounted on the surface of the mounting substrate 5B by adhesive fixing or the like, and a core end face 34a from which light is emitted or incident is formed at one end where each core 32 of the waveguide sheet 31B intersects. A vertical end face 34 is formed. In addition, a fiber guide groove 38 into which the optical fiber 60 of the fiber array 6 is inserted is provided at the other end where the cores 32 of the waveguide sheet 31B intersect. The fiber guide groove 38 extends linearly along the direction in which the core 32 extends, and the tip is open at the other end of the waveguide sheet 31B. Further, the end face of the core 32 is exposed at the rear end of the fiber guide groove 38.

  The fiber guide groove 38 has a quadrangular cross-sectional shape, and the width of the fiber guide groove 38 is substantially equal to the diameter of the optical fiber 60. Further, the depth of the fiber guide groove 38 is slightly shallower than the diameter of the optical fiber 60.

  Thereby, in the optical waveguide 3B, when the optical fiber 60 is inserted into the fiber guide groove 38, a gap is hardly formed between the outer peripheral surface of the optical fiber 60 and the inner wall surface of the fiber guide groove 38. 60 radial movement is restricted.

  In the optical waveguide 3B, when the optical fiber 60 is inserted into the fiber guide groove 38, the fiber guide groove 38 is formed so that the core 32 of the waveguide sheet 31B and the optical axis of the core of the optical fiber 60 are aligned. Etc. are set.

  Therefore, when the optical fiber 60 is inserted into the fiber guide groove 38, the optical waveguide 3B is aligned so that the optical axis of the optical fiber 60 is aligned with the core 32. The core 32 is configured to be optically coupled, and the optical waveguide 3B and the optical fiber 60 can be coupled by passive alignment with mechanical positioning accuracy.

  Here, the optical fiber 60 inserted into the fiber guide groove 38 is bonded and fixed to the optical waveguide 3B using, for example, a pressing plate (not shown).

  In the optical coupler 1B, the alignment of the optical waveguide 3B and the lens array 4B is formed on the waveguide sheet 31B of the optical waveguide 3B and is in the optical axis direction, similarly to the optical coupler 1A of the first embodiment. A fitting protrusion 40B formed on the lens array 4B is fitted into a tapered positioning groove 30B having a tapered shape in the Y direction.

  By fitting the fitting protrusion 40B into the tapered positioning groove 30B having a taper shape in the optical axis direction, the manufacturing accuracy error of the tapered positioning groove 30B and the fitting protrusion 40B is converted into a positional deviation in the optical axis direction. Then, alignment in the X direction, which is one direction perpendicular to the optical axis, is performed.

  Further, the height positioning protrusion 37B formed on the lens array 4B is fitted into the height positioning groove 37B formed on the waveguide sheet 31B of the optical waveguide 3B, so that it is in another direction perpendicular to the optical axis. Positioning in the Z direction is performed.

  In the optical coupler 1B, the depth of the tapered positioning groove 30B is increased by removing the under cladding below the tapered positioning groove 30B in the formation process of the under cladding 33a of the waveguide sheet 31B. As a result, the fitting protrusion 40B of the lens array 4B is easily caught in the tapered positioning groove 30B, and alignment is easier.

  In addition, the bottom surface of the fitting protrusion 40B is configured to float without contacting the mounting substrate 5B which is the bottom surface of the tapered positioning groove 30B. The alignment in the Z direction, which is the other direction perpendicular to the optical axis, is high. The configuration is performed only on the bottom surface of the protrusion 45B.

  For this reason, the length in the optical axis direction of the protrusion 45B for raising the height is increased, and the length in the optical axis direction of the height positioning groove 37B is correspondingly increased. Stability during the fitting process is improved by preventing the lens array 4B from tilting.

<Configuration Example of Optical Coupler of Third Embodiment>
FIG. 7 is a configuration diagram illustrating an example of the optical coupler according to the third embodiment. FIG. 7A is a plan view of the optical coupler 1C according to the third embodiment, and FIG. It is a sectional side view of the optical coupler 1C.

  The optical coupler 1C of the third embodiment includes a laser array 2C, an optical waveguide 3C, and a lens array 4C, and the laser array 2C and the lens array 4C are optically coupled via the optical waveguide 3C.

  In the optical waveguide 3C, a waveguide sheet 31C is mounted on the surface of the mounting substrate 5C on which the laser array 2C is mounted on the mounting portion 50 by adhesive fixing or the like.

  The waveguide sheet 31C includes a plurality of, in this example, 8-channel cores 32 in accordance with the light emitting elements of the laser array 2C, and a core end face 34a from which light is emitted or incident at one end where each core 32 intersects. Is formed.

  The waveguide sheet 31 </ b> C includes an inclined end surface 35 in which a reflection surface 35 a that reflects light is formed at the other end where the cores 32 intersect.

  Furthermore, the waveguide sheet 31 </ b> C includes a pitch conversion unit 39 that changes the pitch of the core 32 between the vertical end surface 34 and the inclined end surface 35. The pitch converter 39 is configured as an S-shaped waveguide having a curved portion so that the interval between the cores 32 gradually increases from the reflecting surface 35a side toward the core end surface 34a side.

  Thereby, the optical waveguide 3C can be different in pitch between the core end surface 34a on the vertical end surface 34 side of the waveguide sheet 31C and the pitch of the reflection surface 35a on the inclined end surface 35 side, and is aligned with the reflection surface 35a. The pitch of the light emitting elements of the laser array 2C and the pitch of the lenses 41C of the lens array 4C aligned with the core end surface 34a can be made different.

  For example, when a laser array and a lens array are coupled by an optical waveguide having a linear core, the lens pitch is the same as the light emitting element pitch, and the lens diameter is determined by the light emitting element pitch.

  On the other hand, when the laser array 2C and the lens array 4C are coupled by the optical waveguide 3C provided with the pitch conversion unit 39, the pitch of the lenses 41C can be made larger than the pitch of the light emitting elements, and is defined by the pitch of the light emitting elements. A lens having a diameter larger than the diameter can be used.

  In the optical coupler 1C, the alignment of the optical waveguide 3C and the lens array 4C is formed on the waveguide sheet 31C of the optical waveguide 3C and is in the optical axis direction, similarly to the optical coupler 1A of the first embodiment. A fitting protrusion 40C formed on the lens array 4C is fitted into a tapered positioning groove 30C having a taper shape in the Y direction.

  By fitting the fitting projection 40C into the tapered positioning groove 30C having a taper shape in the optical axis direction, the manufacturing accuracy error of the tapered positioning groove 30C and the fitting projection 40C is converted into a positional deviation in the optical axis direction. Then, alignment in the X direction, which is one direction perpendicular to the optical axis, is performed.

  Further, by fitting the height projections 45C formed integrally with the fitting projections 40C into the lens array 4C into the height positioning grooves 37C formed in the waveguide sheet 31C of the optical waveguide 3C, the optical axis is aligned. Positioning in the Z direction, which is another vertical direction, is performed.

  In the optical coupler 1C, the shape of the fitting projection 40C formed on the lens array 4C is not a triangular shape but a semicircular shape pressed against the tapered positioning groove 30C. When the lens array 4C is manufactured using a mold, it is difficult to mold an acute angle portion. Therefore, by making the fitting protrusion 40C into a semicircular shape, the manufacturing is simplified and the yield is improved. Note that the effect on the alignment between the optical waveguide 3C and the lens array 4C due to the semicircular shape of the fitting protrusion 40C is that the optical coupler 1A of the first embodiment and the optical coupler of the second embodiment. Same as 1B.

  Further, in the optical coupler 1C, the tapered positioning groove 30C of the waveguide sheet 31C is constituted by the positioning groove forming core layer 32a manufactured by patterning the thin film forming the core 32 in the core 32 forming process. .

  FIG. 8 is a perspective view of a main part of a waveguide sheet in which a tapered positioning groove is formed by a core layer. When the tapered positioning groove 30C is formed of a core layer, the over clad 33b above the tapered positioning groove 30C is removed and opened. When the tapered positioning groove 30C is formed of a core layer, the bottom surface of the height positioning groove 37C is preferably formed on the upper surface of the positioning groove forming core layer 32a that is the upper surface of the core layer. In this case, the upper opening of the tapered positioning groove 30C may be configured integrally with the height positioning groove 37C.

  9 and 10 are process diagrams showing an example of a method for manufacturing a waveguide sheet in which a tapered positioning groove is formed by a core layer. Here, FIG. 9 shows an outline of the manufacturing process of the site where the tapered positioning groove 30C is formed, and FIG. 10 shows the outline of the manufacturing process of the site where the height positioning groove 37C is formed.

  First, as shown in FIGS. 9A and 10A, an ultraviolet curable resin is applied on a silicon substrate 100 in a wafer state by spin coating or the like to form a thin film constituting the underclad 33a. After pre-baking, the thin film is cured by irradiating with ultraviolet rays (UV) to form an underclad 33a.

  Next, as shown in FIGS. 9B and 10B, an ultraviolet curable resin having a higher refractive index than that of the underclad 33a is formed on the underclad 33a formed on the silicon substrate 100 by spin coating or the like. The core layer is formed with the thin film 110 that forms the bottom surface of the core 32, the tapered positioning groove 30C, and the height positioning groove 37C. Then, the core 32, the tapered positioning groove 30C, and the height positioning groove 37C are irradiated with ultraviolet rays through the mask 103 on which the pattern of the bottom surface of the core 32, the tapered positioning groove 30C, and the height positioning groove 37C is formed. The portion forming the bottom surface of the height positioning groove 37C is cured, and the portions other than the bottom surface forming portions of the core 32, the tapered positioning groove 30C and the height positioning groove 37C are removed by solution development, and FIGS. As shown in (c), a positioning groove-forming core layer 32a having a core 32 and a tapered positioning groove 30C in a predetermined pattern and serving as the bottom surface of the height positioning groove 37C is formed.

  Next, as shown in FIGS. 9D and 10D, a positioning groove forming core having an undercladding 33a formed on the silicon substrate 100, a core 32 having a predetermined pattern, and a tapered positioning groove 30C. On the layer 32a, the same ultraviolet curable resin as the underclad 33a is applied by spin coating or the like to form the thin film 111 constituting the overclad 33b, and prebaking is performed. Next, the portion other than the portion where the height positioning groove 37C is formed is cured by irradiating ultraviolet rays through the mask 104 on which the pattern of the height positioning groove 37C is formed by a photolithography process. Then, the portion where the height positioning groove 37C is formed is removed by solution development, and as shown in FIGS. 9E and 10E, the tapered positioning groove 30C and the height positioning groove 37C are formed. The clad 33b is formed.

  As described above, if the taper positioning groove 30C is manufactured by the process of forming the core 32, the core 32 and the positioning groove forming core layer 32a having the taper positioning groove 30C can be formed with the same mask. 32 and the taper positioning groove 30C can be increased in relative positional accuracy up to mask manufacturing accuracy.

  If the taper positioning groove is made using an overcladding layer, the relative position accuracy with the core will be deteriorated by the mask alignment accuracy, but the groove depth can be increased, and it will be caught by the fitting protrusion. Improves the assembly.

  Further, by forming the bottom surface of the height positioning groove 37C on the top surface of the positioning groove forming core layer 32a integral with the tapered positioning groove 30C, the center of the core 32 in the height direction and the height positioning groove 37C are formed. The position accuracy with respect to the bottom surface can be increased.

  Now, the optical coupler 1C of the third embodiment shown in FIG. 7 further includes a configuration for application to an optical connector or a receptacle type optical transmission module.

  That is, the optical coupler 1C includes a tapered portion 46 on the side surface of the lens array 4C. The tapered portion 46 is configured by forming inclined surfaces whose width gradually decreases toward the lens 41C side on two opposing side surfaces of the lens array 4C.

  The optical coupler 1C is attached to the ferrule member 7A. The ferrule member 7A includes a positioning recess 70 in which the optical coupler 1C is fitted. The positioning recess 70 has a shape that matches the tapered portion 46 formed in the lens array 4C of the optical coupler 1C, and the two inner side surfaces facing each other are tapered.

  The tapered portion 46 of the lens array 4C and the positioning recess 70 of the ferrule member 7A are tapered along the Y direction that is the optical axis direction of the lens 41C. As a result, when the optical coupler 1C is mounted in the positioning recess 70 of the ferrule member 7A, and the taper portion 46 of the lens array 4C is pressed and fixed to the positioning recess 70 of the ferrule member 7A, the optical coupler 1C becomes the ferrule. The position in the X direction perpendicular to the optical axis is aligned with the member 7A.

  In this way, the fitting of the optical coupler 1C and the ferrule member 7A is performed by bringing the concave portion and the convex portion having a tapered shape into contact with each other, thereby fitting the optical coupler 1C and the ferrule member 7A with alignment. It can be done easily.

<Configuration Example of Optical Connector and Receptacle Type Optical Transmission Module of this Embodiment>
FIG. 11 is a configuration diagram illustrating an example of the optical connector and the receptacle-type optical transmission module according to the present embodiment. The optical connector 8 of the present embodiment has a configuration similar to that of the optical coupler 1C described in FIG. 7, and is coupled to the fiber array 6 instead of the laser array.

  That is, the optical connector 8 includes a fiber array 6, an optical waveguide 3D, and a lens array 4C, and the fiber array 6 and the lens array 4C are optically coupled via the optical waveguide 3D.

  The optical waveguide 3D includes a fiber guide groove 38 into which the optical fiber 60 of the fiber array 6 is inserted at the other end where the cores 32 of the waveguide sheet 31D having the pitch conversion section 39 intersect. The optical fiber 60 and the core of the optical waveguide 3D are coupled to each other by inserting and fixing the optical fiber 60 to 38.

  In the optical connector 8, the alignment of the optical waveguide 3D and the lens array 4C is formed on the waveguide sheet 31D of the optical waveguide 3D, as in the optical coupler 1C of the third embodiment. A fitting protrusion 40C formed on the lens array 4C is fitted into a tapered positioning groove 30C having a tapered shape in the direction.

  By fitting the fitting projection 40C into the tapered positioning groove 30C having a taper shape in the optical axis direction, the manufacturing accuracy error of the tapered positioning groove 30C and the fitting projection 40C is converted into a positional deviation in the optical axis direction. Then, alignment in the X direction, which is one direction perpendicular to the optical axis, is performed.

  Further, the height positioning projection 37C formed on the lens array 4C is fitted into the height positioning groove 37C formed on the waveguide sheet 31D of the optical waveguide 3D, so that the other direction perpendicular to the optical axis is obtained. Positioning in the Z direction is performed.

  Further, the optical connector 8 includes a tapered portion 46 on the side surface of the lens array 4C, and the lens array 4C to which the optical waveguide 3D is bonded is attached to the ferrule member 7B. The ferrule member 7B includes a positioning recess 70 into which the lens array 4C is fitted. When the taper portion 46 of the lens array 4C is pressed and fixed to the positioning recess 70 of the ferrule member 7B, the lens array 4C is fixed to the ferrule member 7B. Is aligned with the position in the X direction perpendicular to the optical axis.

  The receptacle-type optical transmission module 9 of the present embodiment includes the optical coupler 1C described with reference to FIG. In the optical coupler 1C, the ferrule member 7A is attached to the sleeve 90. The sleeve 90 includes a guide portion 91 having a shape that matches the outer shape of the ferrule member 7A and the ferrule member 7B of the optical connector 8. In the optical coupler 1C, the ferrule member 7A is inserted into the guide portion 91 of the sleeve 90 and bonded and fixed. Has been. In the optical connector 8, the ferrule member 7 </ b> B can be inserted into and removed from the guide portion 91 of the sleeve 90.

  Accordingly, when the optical connector 8 is inserted into the sleeve 90 of the optical transmission module 9, the ferrule member 7 </ b> B is guided by the guide portion 91, so that the optical coupling attached to the same sleeve 90 as the lens 41 </ b> C of the optical connector 8. The optical axis of the lens 41C of the device 1C is aligned, and the optical transmission module 9 and the fiber array 6 are coupled.

  As described above, when the optical connector 8 is connected to the optical transmission module 9, the light emitted from the laser array 2 </ b> C enters the reflection surface 35 a from the lower surface of the waveguide sheet 31 </ b> C, and is totally reflected at the boundary with air. Is incident on.

  The light that has entered the core 32 is propagated through the core 32, is emitted from the core end surface 34a, and is incident on the lenses 41C of the lens array 4C. The light emitted from the core end surface 34a at a predetermined radiation angle passes through the lens 41C to become parallel light and is emitted from the lens 41C.

  The light emitted from the lens 41C of the optical transmission module 9 enters the lens 41C of the optical connector 8. The light incident on the lens 41 </ b> C is collected on the core end surface 34 a of the waveguide sheet 31 </ b> D and is incident on the core 32. The light incident on the core 32 propagates through the core 32 and enters the optical fiber 60 mounted in the fiber guide groove 38. The light incident on the optical fiber 60 is propagated through the optical fiber 60 and received by, for example, a receiving device (not shown).

  The optical transmission module 9 of this example combines an 8-channel laser array 2C and a fiber array 6 having eight optical fibers 60, and functions as an 8-channel optical transmission module.

  In the optical transmission module 9, a laser array is used as a light emitting device. However, it is obvious that the optical transmission module 9 can also be applied to an optical receiving module by using a photodiode as a light receiving device. Further, by using both a laser array and a photodiode, it can be applied to an optical transceiver module. Further, the number of channels can be any number from 1 channel to 8 channels or less or 8 channels or more. In addition, an optical waveguide having a function of demultiplexing or multiplexing can be used by branching a single core into a plurality of parts or joining a plurality of cores into one.

  The optical connector 8 and the optical transmission module 9 of this embodiment are an optical system in which a collimator lens is opposed as the lens 41C. When the lens diameter is increased to increase the beam diameter of parallel light, the optical axis vertical direction The allowable range for the positional deviation between the lenses increases.

  For this reason, in order to manufacture an optical connector that is resistant to displacement, it is necessary to increase the lens diameter. On the other hand, many fiber ribbon cables and light emitting / receiving device arrays that are commercially available as fiber arrays have a pitch of 250 μm. In order to increase the lens diameter to 250 μm or more, a commercially available fiber ribbon cable or light emitting / receiving device having a prescribed pitch can be obtained by combining the lens array, the laser array, and the fiber array via an optical waveguide having a pitch conversion section. Can be easily joined to a lens array having a desired large-diameter lens.

  Further, in the optical connector 8 and the optical transmission module 9 according to the present embodiment, the lens array and the ferrule member are fitted by bringing a concave portion and a convex portion having a tapered shape in the Y direction that is the optical axis direction into contact with each other. Thus, the lens array is aligned with the ferrule member in the X direction perpendicular to the optical axis.

  Then, the ferrule member 7A of the optical transmission module 9 and the ferrule member 7B of the optical connector 8 are inserted into the sleeve 90 and aligned so that the optical transmission module 9 and the optical connector 8 are positioned in the direction perpendicular to the optical axis. Are matched.

  Now, in the optical connector 8 and the optical transmission module 9, the fitting of the lens array and the ferrule member is performed by bringing a concave portion and a convex portion having a tapered shape in the Y direction which is the optical axis direction into contact with each other. As a result, a displacement in the optical axis direction occurs.

  On the other hand, since the optical connector 8 and the optical transmission module 9 collimate the light emitted from the optical transmission module 9 by the lens 41C and enter the lens 41C of the optical connector 8, the positional deviation in the optical axis direction is caused. On the other hand, it is very insensitive, and even if the positional accuracy in the optical axis direction is lowered, the coupling efficiency is hardly affected.

  In this embodiment, the joint portion between the lens array and the ferrule member is provided with a tapered shape only in the width (lateral) direction, but may be provided in the longitudinal (height) direction. This makes it possible to perform both vertical and horizontal alignments perpendicular to the optical axis.

  Further, the portion provided with the taper shape may be only the portion serving as a reference for alignment between the lens array and the fiber array, not the entire outer shape. Furthermore, although the taper shape is a shape that expands toward the rear side from the lens, an inverse taper shape that narrows toward the rear side may be used.

<Effects of optical coupler, optical connector, and optical transmission module of each embodiment>
In the optical coupler of each embodiment, as a configuration for aligning the optical waveguide and the lens array, the tapered positioning groove and the tapered positioning groove having a tapered shape in the optical axis direction are fitted to each other. The manufacturing accuracy error of the fitting protrusion can be converted into a positional shift in the optical axis direction. In the coupling between the optical waveguide and the lens array, the positional deviation accuracy in the optical axis vertical direction is severe, but the positional deviation accuracy in the optical axis direction is gentler than that in the optical axis vertical direction. Thereby, loss of optical coupling can be reduced at a low cost without strict positional deviation accuracy.

  By manufacturing the tapered positioning groove using the core layer, the relative positional accuracy between the core and the tapered positioning groove can be increased to almost the accuracy of the mask, and high-accuracy alignment can be performed.

  On the other hand, when the taper positioning groove is manufactured using the over clad layer, the relative positional accuracy with the core is deteriorated by the mask alignment accuracy at the time of forming the core and the taper positioning groove. It is possible to deepen the depth, the hooking with the fitting protrusion is improved, and the fitting process between the optical waveguide and the lens array is simplified.

  Also, with respect to the alignment in the height direction, the relative accuracy between the center in the height direction of the core and the alignment reference plane is obtained by using the upper surface of the undercladding layer of the waveguide sheet or the upper surface of the core layer as a reference plane. It is possible to increase the film thickness accuracy of the core and perform highly accurate alignment.

  In the configuration in which the optical fiber is coupled to the optical waveguide, the coupling between the lens array and the fiber array is simplified by providing a fiber guide groove that performs alignment by inserting the optical fiber into the optical waveguide.

  In a configuration in which a light receiving and emitting device is coupled to an optical waveguide, a surface type device that receives and emits light perpendicularly to the substrate is used, and a 45-degree reflective surface is formed on the optical waveguide, so that mounting in passive alignment is easy. The manufacturing cost can be reduced.

  In addition, by manufacturing the optical waveguide using a polymer waveguide material having photosensitivity, each positioning groove and fiber guide groove can be easily and accurately manufactured using a photolithography process. it can.

  Furthermore, by providing the optical waveguide with a pitch conversion function, a light receiving / emitting device or a fiber array having an arbitrary pitch can be coupled to a lens array having an arbitrary pitch, and the diameter of the lens can be increased.

  In addition, by attaching a tapered shape to the outer shape of the lens array, it is possible to easily align with the ferrule member, and the two ferrule members are opposed to each other and inserted into a sleeve substantially equal to the outer shape of the ferrule member. With this configuration, the optical axes of the lenses are aligned, and a receptacle-type optical transmission module and optical connector can be easily manufactured.

  And since the emitted light is collimated by the lens with the optical transmission module and the optical connector, the structure is strong against misalignment, and the manufacturing cost can be reduced. Further, if the optical waveguide has a pitch conversion function and uses a large-diameter lens, the positional deviation accuracy can be further relaxed.

  The present invention is applied to an optical connector or an optical transmission module used when an optical communication system using an optical fiber is constructed at home or the like.

It is a block diagram which shows an example of the optical coupler of 1st Embodiment. It is a block diagram which shows an example of the optical coupler of 1st Embodiment. It is process drawing which shows the example of a manufacturing method of the waveguide sheet | seat which forms a taper-shaped positioning groove | channel by an over clad layer. It is process drawing which shows the example of a manufacturing method of the waveguide sheet | seat which forms a taper-shaped positioning groove | channel by an over clad layer. It is operation | movement explanatory drawing which shows the effect of the alignment by a taper-shaped positioning groove and the protrusion for fitting. It is a block diagram which shows an example of the optical coupler of 2nd Embodiment. It is a block diagram which shows an example of the optical coupler of 3rd Embodiment. It is a principal part perspective view of the waveguide sheet | seat which formed the taper-shaped positioning groove | channel with the core layer. It is process drawing which shows the example of a manufacturing method of the waveguide sheet | seat which forms a taper-shaped positioning groove | channel by a core layer. It is process drawing which shows the example of a manufacturing method of the waveguide sheet | seat which forms a taper-shaped positioning groove | channel by a core layer. It is a block diagram which shows an example of the optical connector and receptacle type | mold optical transmission module of this Embodiment.

Explanation of symbols

  1A, 1B, 1C ... optical coupler, 2A, 2B, 2C ... laser array, 3A, 3B, 3C, 3D ... optical waveguide, 4A, 4B, 4C ... lens array, 5A ... -Mounting substrate, 6 ... Fiber array, 7A, 7B ... Ferrule member, 8 ... Optical connector, 9 ... Optical transmission module, 30A, 30B, 30C ... Tapered positioning groove, 31A, 31B, 31C, 31D ... waveguide sheet, 32 ... core, 33a ... under clad, 33b ... over clad, 34 ... vertical end face, 34a ... core end face, 35 ... Inclined end surface, 35a ... reflective surface, 36A ... positioning surface, 37A, 37B, 37C ... height positioning groove, 38 ... fiber guide groove, 39 ... pitch converter, 40A, 40B, 40C ... Projection for fitting, 41A, 41B, 41C ... lens, 42A ... lens forming part, 43A ... mounting part, 44A ... abutting surface, 45A, 45B, 45C ... projection for raising height 50 ... Mounting part, 60 ... Optical fiber, 70 ... Positioning recess, 90 ... Sleeve, 91 ... Guide part

Claims (13)

A lens member having at least one lens;
The lens member includes at least one core through which light is propagated, and a core end surface of the core from which the light is emitted or incident is arranged according to the lens, and the core is optically coupled to the lens. An optical waveguide to be joined with,
A fitting portion configured by forming a convex portion at a joint portion between the lens member and the optical waveguide;
The lens member and the optical waveguide are provided with a concave portion where the fitting portion is fitted, and a positioning portion that aligns the optical axis of the lens and the core end surface of the core. ,
The fitting portion and the positioning portion are in contact with each other so that at least a part thereof has a tapered shape in which one side becomes narrower along the optical axis direction. The positioning portion is formed by opening a surface and an upper surface where the core end surface of the optical waveguide is exposed, and the lens member is inserted into the fitting portion from the opening portion of the positioning portion and pushed to the positioning portion. The optical coupler according to claim 1, wherein the alignment is performed by contact. In the optical waveguide, the core is formed on the upper surface of the undercladding, and the overcladding is formed on the upper surface of the undercladding on which the core is formed,
The optical coupler according to claim 1, wherein the positioning portion is formed by patterning a thin film that forms the over clad. In the optical waveguide, the core is formed on the upper surface of the undercladding, and the overcladding is formed on the upper surface of the undercladding on which the core is formed,
The optical coupler according to claim 1, wherein the positioning portion is formed by patterning a thin film that forms the core. In the optical waveguide, the core is formed on the upper surface of the undercladding, and the overcladding is formed on the upper surface of the undercladding on which the core is formed,
The optical waveguide includes a height positioning portion that forms a bottom surface by exposing the top surface of the underclad or the top surface of the core, and
The height adjustment fitting part which presses against the bottom face of the height positioning part to the lens member, and aligns the optical axis in the core end face of the lens and the core is provided. Item 5. The optical coupler according to Item 1. 2. The optical coupler according to claim 1, comprising either one of a light emitting device and a light receiving device coupled to the lens member via the core of the optical waveguide, or both the light emitting device and the light receiving device. An optical fiber coupled to the lens member via the core of the optical waveguide is provided, and the optical waveguide is provided with a fiber guide groove into which the optical fiber is inserted and aligned. Item 5. The optical coupler according to Item 1. The optical coupler according to claim 1, wherein the optical waveguide includes a pitch conversion unit that expands a pitch of the core toward the lens. In the optical waveguide, the core is formed on an upper surface of an underclad, an overclad is formed on an upper surface of the underclad on which the core is formed, and the core, the underclad and the overclad have photosensitivity. The optical coupler according to claim 1, wherein the optical coupler is made of a polymer material and patterned by a photolithography process. A taper portion having a tapered shape in which at least a part of the outer shape of the lens member becomes thinner along the optical axis direction of the lens,
A positioning recess having a shape that matches the tapered portion of the lens member, and a ferrule member that aligns the lens member by inserting the lens member into the positioning recess. Item 5. The optical coupler according to Item 1. The optical coupler according to claim 1, wherein the lens member is manufactured by integral molding using a mold. A lens member having at least one lens;
The lens member includes at least one core through which light is propagated, and a core end surface of the core from which the light is emitted or incident is arranged according to the lens, and the core is optically coupled to the lens. An optical waveguide to be joined with,
An optical fiber coupled to the lens member via the core of the optical waveguide;
A fitting portion configured by forming a convex portion at a joint portion between the lens member and the optical waveguide;
The lens member and the optical waveguide are provided with a concave portion where the fitting portion is fitted, and a positioning portion that aligns the optical axis of the lens and the core end surface of the core. ,
The optical connector according to claim 1, wherein at least a part of the fitting portion and the positioning portion are in contact with each other so as to have a taper shape in which one side becomes narrower along the optical axis direction. A lens member having at least one lens;
The lens member includes at least one core through which light is propagated, and a core end surface of the core from which the light is emitted or incident is arranged according to the lens, and the core is optically coupled to the lens. An optical waveguide to be joined with,
Either a light emitting device and a light receiving device or both a light emitting device and a light receiving device coupled to the lens member via the core of the optical waveguide;
A fitting portion configured by forming a convex portion at a joint portion between the lens member and the optical waveguide;
The lens member and the optical waveguide are provided with a concave portion where the fitting portion is fitted, and a positioning portion that aligns the optical axis of the lens and the core end surface of the core. ,
The receptacle-type optical transmission module, wherein the fitting portion and the positioning portion are in contact with each other so that at least a part thereof has a tapered shape in which one side is narrower along the optical axis direction.

Images