JP2005172897A - Optical communication module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical communication module in which an optical fiber, a diffraction element, a light emitting element and a light receiving element of the optical communication module which transmits and receives an optical signal are accurately and easily aligned and which is simply handled, and to provide a diffraction element for the optical communication module. <P>SOLUTION: The optical communication module 10 is provided with: the light emitting element which emits an optical signal toward the terminal 2 of an optical fiber 1; the light receiving element which receives the optical signal from the terminal 2 of the optical fiber 1; a diffraction lens 13 arranged between the terminal of the optical fiber, and the light emitting element and the light receiving element and on which lens an alignment mark is formed; a first case 14 which fixes the light emitting element and the light receiving element; and a second case 16 which fixes the diffraction lens and the terminal of the optical fiber and composed freely detachably with respect to the first case. The second case is provided with a first fixing part 31 which fixes the diffraction lens and a second fixing part 32 which fixes the terminal of the optical fiber, and the second fixing part has an alignment part formed for aligning the diffraction lens with an alignment mark of the diffraction lens with respect to the second case. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical communication module used for an optical communication terminal or the like.

  An optical communication system using an optical transmission line such as an optical fiber simultaneously transmits a plurality of optical signals having different wavelengths through an optical fiber by WDM (wavelength division multiplexing), and bidirectional optical communication to an optical signal transmission / reception terminal. A module is used. In general, when a high-performance optical communication module is manufactured, an optical waveguide is generally used, but in this case, the production cost becomes enormous. Therefore, a space-based optical communication module (mainly composed of optical fibers, diffractive lenses, light-emitting elements such as laser diodes, and light-receiving elements such as photodiodes) that is low-cost and can reduce the number of components is an optical waveguide type It attracts attention in place of modules (see, for example, Patent Document 1 below).

However, in the spatial optical communication module, the alignment of each optical component is difficult because the waveguide is not used. In general, a spatial optical communication module has a structure in which the lens, the light receiving element, and the light emitting element can be flexibly shifted when alignment is performed. Because the alignment position was actively adjusted, a large assembly cost was required.
Japanese Patent Application Laid-Open No. 07-104154

  In view of the problems of the prior art as described above, the present invention aligns (positions) an optical fiber, a diffraction grating, a light emitting element, a light receiving element, and the like of an optical communication module that transmits and receives optical signals. It is an object of the present invention to provide an optical communication module that can accurately and easily be assembled and that can be easily assembled, and a diffraction grating for the optical communication module.

  In order to achieve the above object, an optical communication module according to the present invention includes a light emitting element that emits an optical signal toward an end of an optical fiber, a light receiving element that receives an optical signal from the end of the optical fiber, and the light A diffraction grating disposed between a fiber end and the light emitting element and the light receiving element and having an alignment mark formed thereon, a first housing for fixing the light emitting element and the light receiving element, the diffraction grating and the light A second housing configured to fix a fiber end and to be detachable from the first housing, and the second housing includes a diffraction grating fixing portion that fixes the diffraction grating; An end fixing portion for fixing an end of the optical fiber, and the diffraction grating fixing portion is an array formed for aligning the diffraction grating with the alignment mark of the diffraction grating with respect to the second housing. Characterized in that it has a reinforcement portion.

  According to this optical communication module, the optical fiber is attached and fixed to the terminal fixing portion in the second casing of the optical communication module that transmits and receives optical signals, and the diffraction grating is aligned with the alignment mark of the diffraction grating fixing portion. Since the diffraction grating can be attached and fixed with high precision by alignment with the portion, alignment between the optical fiber and the diffraction grating can be performed accurately and easily. In addition, since the second casing in which the diffraction grating and the end of the optical fiber are fixed is detachable from the first casing in which the light emitting element and the light receiving element are fixed, the optical communication can be easily assembled. A module can be realized.

  In the optical communication module, the second casing is formed in a cylindrical shape, and the center of the hole of the terminal fixing portion and the center of the hole of the diffraction grating fixing portion coincide with the central axis of the cylindrical body. With such a configuration, alignment between the optical fiber and the diffraction grating can be performed with high accuracy.

  The hole of the terminal fixing part is formed by machining with reference to the outer surface of the cylindrical body, and the ferrule attached to the terminal of the optical fiber is attached to the hole of the terminal fixing part, thereby Can be accurately fixed to the second housing.

  Preferably, the alignment mark of the diffraction grating is formed in a groove shape or a convex shape, and the alignment portion of the diffraction grating fixing portion is formed in a convex shape or a groove shape so as to be fitted to the alignment mark.

  The alignment marks of the diffraction grating are preferably formed concentrically for alignment of the axis. The alignment mark of the diffraction grating is preferably formed linearly so as to pass through the center of the circle of the diffraction grating for alignment in the circumferential direction of the diffraction grating.

  The diffraction grating may be formed on at least one surface of the lens.

  Further, the alignment marks of the diffraction grating can be formed with high accuracy by forming them by an electron beam drawing method. In this case, the alignment mark can be formed on the diffraction grating forming die together with the diffraction grating pattern by the electron beam drawing method.

  Moreover, it can form with sufficient precision by forming the alignment part of the said diffraction grating fixing | fixed part by machining.

  In addition, the diffraction grating fixing portion and the terminal fixing portion are formed so that the diffraction grating and the end of the optical fiber in the second casing are at a constant distance, so that the end of the diffraction grating and the optical fiber are formed. The distance between and can be made constant accurately.

  The first housing may include an attachment portion that is attached by fitting an outer peripheral portion of the second housing, and the outer peripheral portion and the attachment portion may be formed by machining. Therefore, the optical fiber and the diffraction grating fixed to the second casing with high accuracy can be positioned with accurate alignment with respect to the light emitting element and the light receiving element fixed to the first casing.

  In this case, it is preferable that the mounting portion of the first housing and the outer peripheral portion of the second housing have a positioning portion for positioning in the circumferential direction.

  The diffraction grating according to the present invention is characterized in that the alignment mark in the above-described optical communication module is formed by an electron beam drawing method. Thereby, it is possible to obtain a diffraction grating in which alignment marks are accurately formed. In this case, the alignment mark can be formed on the diffraction grating forming die together with the diffraction grating pattern by an electron beam drawing method.

  According to the optical communication module of the present invention, it is possible to accurately and easily align and fix the optical fiber, diffraction grating, light emitting element, light receiving element, etc. of the optical communication module that transmits and receives optical signals. Easy to assemble. In addition, it is possible to provide a diffraction grating in which alignment marks necessary for incorporation in an optical communication module are formed with high accuracy.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a side view schematically showing the basic configuration of the optical communication module of the present embodiment.

  As shown in FIG. 1, an optical communication module 10 according to the present embodiment includes a light emitting element 11 composed of a laser diode or the like, a light receiving element 12 composed of a photodiode or the like, a light emitting element 11 and a light receiving element 12, and A first housing 14 that accommodates the light, a diffractive lens 13 having a diffractive surface 15 on which a diffraction grating is formed, and a light that accommodates the diffractive lens 13 so that an optical signal can enter and exit the diffractive lens 13. A second housing 16 for fixing the end 2 of the fiber 1.

  The second casing 16 is configured to be detachable from the first casing 14 so that the diffractive lens 13 is positioned close to the outside of the first casing 14. A collimator lens 17 is disposed in front of the can of the light emitting element 11, and a collimator lens 18 is disposed in front of the can of the light receiving element 12.

  As shown in FIG. 1, in the optical communication module 10, the transmission optical signal emitted from the light emitting element 11 enters the diffractive lens 13 as shown by the broken line in the figure, and is transmitted through the optical fiber by the diffractive lens 13 without being diffracted. 1 is condensed at the end 2 of the optical fiber 1 and transmitted through the optical fiber 1. In this way, the transmission optical signal is transmitted from the optical communication module 10 via the optical fiber 1.

  On the other hand, a received optical signal transmitted through the optical fiber 1 and having a wavelength different from that of the transmitted optical signal enters the diffraction lens 13 from the end 2 of the optical fiber 1 and is diffracted as shown by the solid line in the figure. The light is refracted and incident on the light receiving element 12, and the received light signal is converted into an electric signal by the light receiving element 12 and can be monitored. Thus, the received optical signal is introduced into the optical communication module 10 through the optical fiber 1.

  The optical communication module 10 is used, for example, such that the light emitting element 11 and the light receiving element 12 side are connected to a device terminal such as a personal computer via a connection device such as a router or a LAN, and the optical fiber 1 is connected to an external communication business. It extends to the person's office and enables optical communication between the two.

  The above transmission optical signal and reception optical signal have different wavelengths within the range of 1.2 to 1.6 μm, for example, the wavelength of the transmission optical signal is 1.3 μm, and the wavelength of the reception optical signal is 1.5 μm. It is.

  Next, a specific configuration of the optical communication module in FIG. 1 will be described with reference to FIGS. 2, 3, 4, and 5.

  FIG. 2 is a side cross-sectional view of a second casing configured to be detachable from the first casing of the optical communication module. 3A is a view of the first housing of FIG. 2 as viewed from the direction A, and FIG. 3B is a view of the second housing of FIG. 2 as viewed from the direction B, and FIG. () Is a view of the second housing of FIG. FIG. 4 is a plan view showing alignment marks formed on the diffraction grating of FIG. 5 is a side view (a) showing the positioning claw receiving portion formed on the inner surface of the hole of the first housing in FIG. 2, and a side view (b) showing the positioning claw portion formed on the outer peripheral surface of the second housing. ).

  As shown in FIG. 2 and FIG. 3A, the first housing 14 has a hole formed in a circular shape around the central axis p in the outer wall 14a so that the second housing 16 is detachably fitted. The second housing 16 is formed in the hole 21 on the inner surface 14 b around the hole 21, the cylindrical portion 22 protruding in a cylindrical shape from the outer periphery of the hole 21, and the screw portion 23 formed on the outer peripheral surface thereof. And a cover member 20 that is positioned so as to cover the diffractive lens 13 when fitted and removes stray light. The covering member 20 is blackened so as to absorb light.

  As shown in FIG. 2, the second housing 16 is formed in a cylindrical shape as a whole, and a hollow portion 30 is formed in a columnar shape around the central axis p ′ of the cylindrical body, and the first housing 14 side. The end portion 2 of the optical fiber 1 is fixed and connected to the first fixing portion 31 of the diffractive lens 13 provided on the end surface 35a of the optical fiber 1 so as to face the diffractive lens 13 across the hollow portion 30. A second fixing portion 32.

  A hole 38 having a larger diameter than the hollow part 30 is formed in a circular shape so that the diffractive lens 13 can enter the first fixing part 31, and a step surface 39 is formed between the hole 38 and the hollow part 30. Is formed.

  In the first fixing portion 31 of the second housing 16, when the diffractive lens 13 is fitted through the hole 38, the diffractive lens 13 comes into contact with the stepped surface 39, and the diffractive lens 13 is positioned in the direction in which the central axis p 'extends.

  2 and 3B, the second fixing portion 32 is formed in a circular hole portion into which the ferrule 3 that holds the end portion 2 of the optical fiber 1 can be fitted. An abutting portion 32a is formed at the tip of the inner side of the hole of the second fixing portion 32 so that the end portion 2 of the optical fiber 1 abuts with the ferrule 3, and the end portion of the optical fiber 1 is formed by the abutting portion 32a. 2 is positioned in the direction in which the central axis p ′ extends. Since both the contact portion 32a of the second fixing portion 32 and the step surface 39 of the first fixing portion 31 are machined with reference to the end surfaces 35a and 36b, the accuracy of the distance between the contact portion 32a and the step surface 39 is determined. The end 2 of the optical fiber 1 and the diffractive lens 13 can be attached and fixed with good distance accuracy.

  In addition, the hole portion of the second fixing portion 32 is formed with an introduction port 32b having a tapered shape with a slightly larger diameter at the end face 36b, and the introduction port 32b increases the bonding area between the hole portion and the ferrule 3 and is easy to fix. Yes.

  The central axes of the hole 38 of the first fixing part 31 and the hole of the second fixing part 32 are formed so as to coincide with the central axis p ′ of the second housing 16.

  In addition, the cylindrical body of the second housing 16 is positioned on the first housing 14 side in the direction in which the central axis p ′ extends, and on the end 2 side of the optical fiber 1 with the slightly large diameter large portion 35. The small-diameter portion 36 having a slightly small diameter is provided, and the large-diameter portion 35 fits into the circular hole portion 21 of the first housing 14.

  A fixing ring member 33 can be inserted into the second housing 16 from the small diameter portion 36 side so as to abut on a step 36 a between the large diameter portion 35 and the small diameter portion 36. The fixing ring member 33 has a cylindrical portion 33a having a diameter larger than that of the large diameter portion 35, and a screw portion 34 that can mesh with the screw portion 23 of the cylindrical portion 22 of the first housing 14 is formed on the inner surface of the cylindrical portion 33a. Is formed.

  After the second housing 16 is fitted into the hole 21 of the first housing 14 from the large diameter portion 35, the fixing ring member 33 is inserted from the small diameter portion 36 of the second housing 16 and rotated, thereby The second casing 16 can be attached to the first casing 14 by screwing until the threaded section 34 meshes with the thread section 23 on the first casing 14 side and abuts against the step 36a. Further, the second casing 16 can be detached from the first casing 14 after the fixing ring member 33 is removed by rotating the fixing ring member 33 in the reverse direction. Thus, the second housing 16 can be easily attached to and detached from the first housing 14 by the fixing ring member 33.

  4, the diffractive lens 13 includes a plurality of linear diffraction gratings 15a formed on a circular diffractive surface 15 in a fine concavo-convex structure so as to extend linearly in the horizontal direction in the figure, and a diffractive surface. 15 and an outer peripheral portion 37 provided concentrically with the diffraction surface 15.

  The outer peripheral portion 37 of the diffractive lens 13 includes a circular groove 37a concentrically formed with the diffractive surface 15 and a linear groove formed so as to pass through the center of the circle of the diffractive surface 15 and intersect with the circular groove 37a. 37b, 37c. The circular groove 37 a and the linear grooves 37 b and 37 c of the diffractive lens 13 constitute an alignment mark that serves as a position reference when the diffractive lens 13 is attached to the first fixing portion 31.

  In addition, when the diffraction grating 15a formed on the diffraction surface 15 is formed in an annular shape composed of a plurality of concentric circles, the linear grooves 37b and 37c may be omitted.

  As shown in FIG. 2 and FIG. 3C, the step surface 39 of the first fixing portion 31 of the second housing 16 is formed with a circular protrusion 31 a that protrudes in a circular shape and a linear protrusion. Linear protrusions 31b and 31c are provided. The circular protrusions 31a and the linear protrusions 31b and 31c on the step surface 39 of the first fixing part 31 are fitted to correspond to the circular grooves 37a and the linear grooves 37b and 37c of the outer peripheral part 37 of the diffraction lens 13 shown in FIG. It constitutes, and constitutes an alignment section that fits with the alignment marks of these diffractive lenses 13.

  Since the diffractive lens 13 is attached to the alignment portion of the first fixing portion 31 of the second housing 16 with reference to the alignment mark, it can be attached to the second housing 16 with high accuracy. Further, since the fitting structure is adopted, there is almost no possibility that the shaft or alignment is shifted due to thermal expansion or physical influence, which is preferable.

  Further, the circular groove 37a and the linear grooves 37b and 37c for the alignment mark of the diffraction lens 13 preferably have a depth of about 4 to 20 μm and a width of about 10 to 500 μm, and can be formed by electron beam drawing and dry etching as described later. . The circular projection 31a of the first fixing portion 31 and the alignment portions of the linear projections 31b and 31c are set to dimensions that allow them to be fitted in correspondence with the dimensions of the alignment marks described above.

  Alternatively, the alignment mark provided on the outer peripheral portion 37 of the diffractive lens 13 may be formed in a convex shape, and the alignment portion provided on the step surface 39 of the first fixing portion 31 may be formed in a groove shape.

  As shown in FIGS. 3B and 5C, the outer surface of the large-diameter portion 35 of the second housing 16 protrudes from the outer surface so as to extend in the direction in which the central axis p ′ in FIG. 2 extends. The elongated positioning claws 42 and 43 are formed at two locations in the diameter direction of a circle centered on the central axis p ′. Further, as shown in FIGS. 3A and 5A, the claw portions 42 and 43 of the second housing 16 are notched so as to be able to fit into the inner surface of the hole portion 21 of the first housing 14. -Shaped positioning claw receiving portions 40 and 41 are formed at two locations.

  As shown in FIGS. 5A and 5B, when the second casing 16 is fitted into the hole 21 of the first casing 14 from the large-diameter portion 35, the positioning claws 42 and 43 are positioned to the positioning claw receiving portions. The second casing 16 can be positioned and attached to the first casing 14 in the circumferential direction of FIG.

  The peripheral surface 21a of the circular hole 21 of the first housing 14 described above is accurately machined so as to be an accurate circle for alignment, and the linearity of the outer wall 14a is also accurately machined. . Further, since the light emitting element 11 and the light receiving element 12 of FIG. 1 are accurately positioned with respect to the central axis p of the hole portion 21 in the first housing 14, they are attached with high accuracy.

  Here, the alignment of the light emitting element 11 and the light receiving element 12 in the first housing 14 will be described with reference to FIG. 7 is a view of the first housing 14 and the second housing 16 of the optical communication module of FIG. 2 as viewed from above in FIG. 1 and the light emitting elements 11 and the light receiving elements 12 in the first housing 14. It is a figure (b) which expands and shows a portion.

  As shown in FIGS. 7A and 7B, the central axis p of the first housing 14 coincides with the traveling line of the 0th-order optical signal of light. Therefore, when receiving a received optical signal with zero-order light, a light receiving element 12 such as a photodiode may be installed on the central axis p. Moreover, what is necessary is just to install the light emitting elements 11, such as a laser diode, on the central axis p when transmitting by 0th order light.

  Further, when the central axis (0th-order light position) is used as a reference, the position of ± 1, 2, 3,... By installing the light receiving element 12 or the light emitting element 11 on the first housing 14, the receiving / transmitting positions of the light receiving element 12 and the light emitting element 11 in the first housing 14 and the position of the end 2 of the optical fiber 1 in the second housing 16 are provided. Can be easily aligned.

  Further, the outer peripheral surfaces of the large-diameter portion 35 and the small-diameter portion 36 of the second housing 16 and the end surfaces 35a and 36b thereof are accurately formed by machining such as cutting with respect to the central axis p '. The position / diameter of the hole 38 of the first fixing portion 31, the distance from the end surface 35 a to the step surface 39, and the position / diameter of the hole of the second fixing portion 32, the distance from the end surface 36 b to the contact portion 32 a are The second casing 16 is formed with high precision by machining by cutting or the like with reference to the outer peripheral surfaces and the end surfaces 35a and 36b of the large-diameter portion 35 and the small-diameter portion 36 of the second housing 16. Similarly, the circular protrusion 31a and the linear protrusions 31b and 31c on the step surface 39 of the first fixing portion 31 are also formed with high precision by machining.

  Next, a method for manufacturing a diffractive lens having the alignment mark shown in FIGS. 2 and 4 will be described with reference to FIG. FIG. 6 is a diagram for explaining the procedures (a) to (f) for producing the diffractive lens by the electron beam drawing method. The electron beam drawing method is a method in which a desired drawing pattern is formed by an electron beam on the surface of an optical element such as a diffractive lens, as previously proposed by the present inventors in Japanese Patent Application No. 2002-249614. It can be formed with high precision on the order of submicrons by three-dimensional drawing.

  First, as shown in FIG. 6A, an outer peripheral surface 80a of a base material 80 made of a cylindrical resin material serving as a matrix is cut based on the outer diameter 81 of the base material 80, and an error is 0.5 μm or less. Centering with accuracy. Next, as shown in FIG. 6B, a convex curved surface 82 (or a concave curved surface) that becomes a lens shape by cutting is processed.

  Next, as shown in FIG. 6 (c), the concentric circle 83 is processed with the outer peripheral surface 80a as a reference by cutting, and then the convex curved surface 82 is set with reference to the concentric circle 83 as shown in FIG. 6 (d). The center is aligned and a diffraction grating pattern is formed on the resist by electron beam drawing. Marks for determining the XY axes are processed as necessary. In this case, the resist thickness is about 2 μm, for example.

  Further, as shown in FIG. 6E, for alignment marks (circular grooves 37a and linear grooves 37b and 37c in FIG. 4) for attaching the diffractive lens to the second housing 16 with the concentric circle 83 as a reference. The groove 84 is drawn by an electron beam. The groove 84 is formed with a diameter very close to the diffraction pattern (inside the lens outer shape).

  As shown in the plan view of FIG. 6F, a diffraction pattern is formed on the convex curved surface 82 of the base material 80 manufactured as described above, and the outer peripheral portion thereof (corresponding to the outer peripheral portion 37 of FIG. 4). ) Are formed with circular and linear grooves 84, and an outermost peripheral portion 85 corresponding to the outermost periphery of the diffractive lens 13 is formed on the outer periphery thereof as indicated by a broken line. The groove 84 is formed with a width of about 10 μm and a depth of about 8 μm, for example.

  Next, the substrate 80 is processed by dry etching using a plasma shower or the like, using the resist diffraction grating pattern formed by electron beam drawing and the alignment mark groove 84 as a mask. By this dry etching, the diffraction grating pattern and the groove for the alignment mark are transferred onto the substrate 80. At the time of this transfer, the diffraction pattern is enlarged about 1 to 6 times in the depth direction, and the depth of the groove for the alignment mark is 8 μm or more.

  Next, an electroformed mold is manufactured using a base material formed by dry etching as a base material, and a diffractive lens is molded by the mold, thereby obtaining the diffractive lens 13 shown in FIGS. Note that the diffractive lens may be press-molded using the base material directly as a mother mold.

  Next, a procedure for assembling the second housing 16 and attaching and fixing the second housing 16 to the first housing 14 with respect to the optical communication module 10 of FIGS. 2 to 5 will be described.

  First, the optical fiber 1 is inserted from the ferrule 3 into the hole of the second fixing portion 32 of the second housing 16 and inserted until the end portion 2 comes into contact with the contact portion 32a. Since the hole of the second fixing portion 32 is processed with high accuracy, the optical fiber 1 and the second housing 16 can be accurately aligned and fixed.

  On the other hand, the diffractive lens 13 is inserted into the hole 38 of the first fixing portion 31 so that the diffractive surface 15 faces the end 2 of the optical fiber 1, and the outer peripheral portion 37 of the diffractive lens 13 is in contact with the step surface 39. Fit. When this fitting is performed, the circular groove 37a and the linear grooves 37b and 37c of the alignment mark of the diffractive lens 13 with respect to the second housing 16 are the circular protrusion 31a and the linear protrusions 31b and 31c which are the alignment portions on the second housing 16 side. 4 so that the diffraction lens 13 can be easily and accurately positioned in the second housing 16 in the central axis p ′ and the circumferential direction, the alignment accuracy is good, and the linear diffraction grating 15a in FIG. Can be accurately aligned in the circumferential direction.

  Further, the hole 38 of the first fixing portion 31 of the first housing 14 and the hole of the second fixing portion 32 of the second housing 16 achieve accurate roundness and side linearity by machining. Therefore, the central axis of the optical fiber 1 and the central axis of the diffractive lens 13 can be matched with high accuracy within, for example, 0.5 μm, and both can be accurately aligned.

  The optical fiber 1 and the diffractive lens 13 are fixed to the fixing portions 31 and 32 of the second housing 16 with, for example, an adhesive. The side surfaces of the fixing portions 31 and 32 are distributed so that the adhesive is evenly distributed. It is desirable to form a hole for venting air.

  Next, after fitting the second housing 16 into the hole 21 of the first housing 14 from the large diameter portion 35, the fixing ring member 33 is rotated to rotate the screw portion 34 and the screw portion 23 on the first housing 14 side. Are screwed and brought into contact with the step 36a, so that the second casing 16 can be attached to the first casing 14, so that the first casing 14 and the second casing 16 are easily assembled. be able to.

  At the time of this assembly, since the peripheral surface 21a of the hole 21 of the first housing and the large diameter portion 35 of the second housing 16 are both machined with high accuracy, the central axes p and p ′ of both are accurate. Match well. In addition, since the positioning claws 42 and 43 of the second housing 16 are fitted to the positioning claws receiving portions 40 and 41 of the first housing 14, the second housing 16 is shown in the drawing with respect to the first housing 14. 3 can be accurately positioned in the circumferential direction. The diffractive lens 13 can be accurately positioned with respect to the first casing 14 because the linear diffraction grating 15a is accurately aligned with the second casing 16 in the circumferential direction.

  As described above, the second housing 16 can be attached and fixed to the first housing 14 after the second housing 16 is assembled. In the second housing 16, the end portions of the diffraction lens 13 and the optical fiber 1 are accurately positioned. It can be aligned accurately and accurately, and the interval accuracy is good. In addition, the light-emitting element 11 and the light-receiving element 12 can be attached to the hole 21 in the first housing 14 with high precision. Since the 2nd housing | casing 16 can be attached with sufficient precision, the light emitting element 11 and the light receiving element 12 can be accurately aligned with respect to the edge part 2 of the optical fiber 1, and the optical communication module 10 can be accurately and easily performed. It becomes possible to assemble.

  Conventionally, spatial optical communication modules have been difficult to align optical components such as diffractive lenses, and the alignment position has been manually adjusted. According to the optical communication module 10 of the embodiment, the diffractive lens 13 and the end portion 2 of the optical fiber 1 are integrally formed in the second housing 16 so that the alignment with respect to the central axial distance and alignment can be easily performed. Since the assembly can be facilitated, the assembly cost can be reduced. In particular, the accuracy in the central axis direction of the end 2 of the optical fiber 1 and the diffractive lens 13 is controlled on the order of submicrons, and the end 2 of the optical fiber 1 is ranked first in the machining accuracy of the second housing 16. Since the position of the diffractive lens 13 is determined, an optical communication module with easy alignment and high accuracy can be configured.

  As described above, the best mode for carrying out the present invention has been described. However, the present invention is not limited to these, and various modifications can be made within the scope of the technical idea of the present invention. For example, when the second casing 16 requires more sufficient airtightness, the first fixing portion 31 and the second fixing portion 32 may be fixed by welding or the like. In addition, the diffractive lens 13 may have a diffractive surface on the first housing 14 side in FIG.

It is a side view which shows roughly the basic composition of the optical communication module of this Embodiment. It is a figure which shows the specific structure of the optical communication module of FIG. 1, Comprising: It is a sectional side view of the 2nd housing | casing comprised so that attachment or detachment was possible with respect to the 1st housing | casing of FIG. 3A is a view of the first housing of FIG. 2 as viewed from the direction A, and FIG. 3B is a view of the second housing of FIG. 2 as viewed from the direction B, and FIG. () Is a view of the second housing of FIG. It is a top view which shows the alignment mark formed in the diffraction grating of FIG. FIG. 3A is a side view showing a positioning claw receiving portion formed on the inner surface of a hole of the first housing in FIG. 2 and a side view showing a positioning claw portion formed on the outer peripheral surface of the second housing. . It is a figure for demonstrating the procedure (a) thru | or (f) which produces the diffraction lens of FIG. 2, FIG. 4 by the electron beam drawing method. FIG. 2A is a view of the first housing 14 and the second housing 16 of the optical communication module of FIG. 2 viewed from above in FIG. 1, and the portions of the light emitting element 11 and the light receiving element 12 in the first housing 14 are enlarged. FIG.

Explanation of symbols

1 Optical fiber 2 End (terminal)
DESCRIPTION OF SYMBOLS 3 Ferrule 10 Optical communication module 11 Light emitting element 12 Light receiving element 13 Diffraction lens 14 1st housing | casing 14a Outer wall 14b Inner surface 15 Diffraction surface 15a Diffraction grating 16 2nd housing | casing 21 Hole (attachment part)
21a Peripheral surface 22 Cylindrical part 23 Screw part 30 Hollow part 31 First fixing part 31a Circular protrusion (alignment part)
31b Linear protrusion (alignment part)
32 2nd fixing | fixed part 32a Contact part 32b Introduction port 33 Fixing ring member 33a Cylindrical part 34 Screw part 35 Large diameter part (outer peripheral part)
35a end face 36 small diameter part 36a step 36b end face 37 outer peripheral part of diffraction lens 37a circular groove (alignment mark)
37b, 37c Straight groove (alignment mark)
38 hole 39 step surface 40, 41 positioning claw receiving portion (positioning portion)
42, 43 Positioning claw part (positioning part)
80 base material 80a outer peripheral surface 81 outer diameter 82 convex curved surface 83 concentric circular line 84 groove 85 outermost peripheral part p central axis p 'central axis

Claims (14)

A light emitting element that emits an optical signal toward the end of the optical fiber;
A light receiving element for receiving an optical signal from a terminal of the optical fiber;
A diffraction grating arranged between an end of the optical fiber and the light emitting element and the light receiving element, and an alignment mark is formed;
A first housing for fixing the light emitting element and the light receiving element;
A second housing configured to fix the diffraction grating and the end of the optical fiber and to be detachable from the first housing;
The second housing includes a diffraction grating fixing part that fixes the diffraction grating, and a terminal fixing part that fixes an end of the optical fiber,
The optical communication module, wherein the diffraction grating fixing part includes an alignment part formed to align the diffraction grating with the alignment mark of the diffraction grating with respect to the second housing. The second casing is configured in a cylindrical shape, and is configured such that the center of the hole of the terminal fixing portion and the center of the hole of the diffraction grating fixing portion coincide with the central axis of the cylindrical body. The optical communication module according to claim 1. The hole portion of the terminal fixing portion is formed by machining on the basis of the outer surface of the cylindrical body, and a ferrule attached to the end of the optical fiber is attached to the hole portion of the terminal fixing portion. Item 3. The optical communication module according to Item 2. The alignment mark of the diffraction grating is formed in a groove shape or a convex shape, and the alignment portion of the diffraction grating fixing portion is formed in a convex shape or a groove shape so as to be fitted to the alignment mark. Item 4. The optical communication module according to Item 1, 2 or 3. 5. The optical communication module according to claim 1, wherein the alignment mark of the diffraction grating is formed concentrically for alignment of an axis. The alignment mark of the diffraction grating is formed in a straight line so as to pass through a circular center of the diffraction grating for alignment in the circumferential direction of the diffraction grating. 2. An optical communication module according to item 1. The optical communication module according to claim 1, wherein the diffraction grating is formed on at least one surface of the lens. 8. The optical communication module according to claim 1, wherein the alignment mark of the diffraction grating is formed by an electron beam drawing method. 9. The optical communication module according to claim 8, wherein the alignment mark is formed on a diffraction grating forming die together with the diffraction grating pattern by the electron beam drawing method. The optical communication module according to claim 1, wherein an alignment portion of the diffraction grating fixing portion is formed by machining. 11. The diffraction grating fixing part and the terminal fixing part are formed so that the diffraction grating in the second housing and the end of the optical fiber are at a constant distance. The optical communication module according to claim 1. 2. The first housing includes an attachment portion to which an outer peripheral portion of the second housing is fitted and attached, and the outer peripheral portion and the attachment portion are formed by machining. The optical communication module of any one of thru | or 11. The optical communication module according to claim 12, wherein the mounting portion of the first housing and the outer peripheral portion of the second housing have a positioning portion for positioning in the circumferential direction. A diffraction grating, wherein the alignment mark in the optical communication module according to any one of claims 1 to 7 is formed by an electron beam drawing method.

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