JP2005250118A - Wavelength multiplexing optical transmitter module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wavelength multiplexing optical transmitter module which is miniaturized. <P>SOLUTION: Two or more light emitting elements are arranged so that the optical axes are mutually in parallel to each other; one end face 2a of an optical waveguide module 2 formed in a rectangular parallelopiped form is faced with these light emitting elements; end parts of two or more branch line cores 3 which incorporate light of each light emitting element is located on this end face 2a of this waveguide module 2 and one trunk core 4 which has gathered the two or more branch line cores 3 is formed inside this waveguide module 2; and the end part of this trunk core 4 is arranged to another end face 2b intersecting perpendicularly to the end face 2a. The optical waveguide module 2 is therefore miniaturized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wavelength division multiplexing optical transmission module that multiplexes and emits light having different wavelengths from a plurality of light emitting elements, and relates to a wavelength division multiplexing optical transmission module that can be miniaturized.

  The wavelength multiplexing optical transmission module includes a plurality of light emitting elements that emit light having different wavelengths, a multiplexing unit that multiplexes these lights and emits them on the same optical axis, and a plurality of drive circuits that respectively drive the light emitting elements. Are configured as one module. Also, the main circuit for controlling the drive circuit may be housed in this module.

  There are various forms of the exterior of the light emitting element, but when a transmission signal is a high frequency in order to perform high-speed communication, it is preferable to use a metal casing in consideration of electromagnetic shielding and heat dissipation. As a form having a metal casing as an exterior, a can type light emitting element module is known in which a light emitting element is accommodated in a cylindrical metal casing and light is emitted from the end face of the cylinder.

  In addition, there are various types of multiplexing means, but a waveguide module may be used in consideration of reduction in the number of parts and downsizing. The multi-channel optical transmission module described in Patent Document 1 uses a waveguide module in which a waveguide layer in which a plurality of cores are formed has a step with respect to a waveguide substrate serving as a base of the waveguide layer. By mounting the light emitting element, the light of each light emitting element is guided to each core. Furthermore, the waveguide module can be used as a multiplexing means by forming a single core in which a plurality of cores are assembled. If this technique is applied to Patent Document 1, a wavelength division multiplexing optical transmission module is constructed. Can do.

  FIG. 8 shows a waveguide module serving as a multiplexing means. As shown in the figure, this waveguide module 81 is formed in a rectangular parallelepiped shape, and ends of a plurality of cores 83 for taking in light of each light emitting element are arranged at substantially constant intervals on one end face 81a, and face this end face 81a. On the end surface 81c, the end of one trunk core 84 in which a plurality of cores 83 are assembled is disposed. Between both end faces 81a and 81c, first, a certain core 83 and an adjacent core 83 are each bent at a predetermined radius R and brought close to each other, and are bent close to each other by being bent at a predetermined radius R in opposite directions. Has been. A core formed by the assembly of these two cores and other similar cores are bent at a predetermined radius R and brought close to each other, and are bent close to each other by being bent oppositely at a predetermined radius R. All the cores 83 are assembled into one main core 84. However, the bend radii R at the 12 positions shown in the figure are not necessarily the same.

JP 2003-14994 A

  As already described, the can type light emitting element module is suitable for high speed communication. However, because the can type light emitting element module is fixed to the step of the waveguide substrate described in Patent Document 1, it is a bond between metal and glass or resin, and a bond between a cylindrical surface and a flat surface. Have difficulty.

  Further, the waveguide module 81 of FIG. 8 has a trunk core from the width (vertical width) in the arrangement direction of the cores 83 and the end of the core 83 in order to secure a space for bending the cores 83 at a predetermined radius R. The width (width) in the direction toward the end of 84 is increased, which is an obstacle to miniaturization of the wavelength division multiplexing optical transmission module.

  Further, since the light emitting element (or the light emitting element module), the drive circuit, and the main circuit are electrical components, they must be mounted on a substrate or connected by wiring. For this reason, securing the board arrangement space and the wiring space is an obstacle to downsizing.

  Accordingly, an object of the present invention is to provide a wavelength division multiplexing optical transmission module that can solve the above-described problems and can be miniaturized.

  In order to achieve the above object, the present invention provides a wavelength division multiplexing optical transmission module that multiplexes and emits light having different wavelengths from a plurality of light emitting elements so that the optical axes of the plurality of light emitting elements are parallel to each other. A plurality of cores (hereinafter referred to as branch cores) that are arranged side by side, face one end face of a waveguide module formed in a rectangular parallelepiped shape on these light emitting elements, and take in the light of each light emitting element to the end face of the waveguide module An end is disposed, and a single core (hereinafter referred to as a trunk core) is formed by assembling the plurality of branch cores inside the waveguide module, and the end of the trunk core is orthogonal to the end face. It is arranged on the end face.

  The waveguide module may have a bottom surface attached to a metal base, the plurality of light emitting elements may be accommodated in a metal cylindrical housing, and the cylindrical housing may be fixed to the base by welding.

  The waveguide module may be bonded to the metal base with an adhesive, and a relief groove for the adhesive may be formed in the metal base.

  A plurality of driving circuits for driving each of the plurality of light emitting elements are mounted on one substrate to form a driving circuit substrate, and the plurality of light emitting elements are mounted on another one substrate to form a light emitting element substrate. And the drive circuit board may be coupled to a common flexible board and the drive circuit board may be attached to the upper surface of the waveguide module.

  The main circuit for controlling the drive circuit may be further mounted on another board to form a main circuit board, and the main circuit board and the drive circuit board may be coupled to a common flexible board.

  The present invention exhibits the following excellent effects.

  (1) The wavelength-multiplexed optical transmission module can be reduced in size.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIGS. 1A and 1B, the wavelength division multiplexing optical transmission module according to the present invention includes four light emitting element modules 1 each having a light emitting element such as a laser diode housed in an exterior. The light-emitting element modules 1 are arranged side by side so that the light-emitting element modules 1 face each other at one end face 2a of the waveguide module 2 formed in a rectangular parallelepiped shape. The ends of the four branch cores 3 to be taken in are arranged, and one trunk core 4 is formed by assembling the four branch cores 3 inside the waveguide module 2. It is arranged on another end surface 2b orthogonal to the end surface 2a.

  As shown in FIG. 2, in the waveguide module 2, the end portions of the four branch cores 3 are arranged at an appropriate interval P on the end surface 2 a. Each branch core 3 extends at a right angle from the end surface 2a, is bent by about 90 ° in the direction of the end surface 2b at a bending radius R, and further extends toward the end surface 2b. The branch line core 3 adjacent to the portion where the branch line core 3 farthest from the end face 2b extends toward the end face 2b is gathered close to the bend radius R. The adjacent branch core 3 is gathered closer to the portion where the gathered core extends toward the end face 2b because of the bending radius R. In this way, the branch line cores 3 are sequentially gathered to form one trunk core 4 in which the four branch line cores 3 are gathered. The main core 4 extends at a right angle toward the end surface 2b, and the end of the main core 4 appears on the end surface 2b.

  As shown in FIG. 3, the waveguide module 2 has a bottom surface attached to a metal base 5. The base 5 has a flat waveguide module mounting surface 5d, a wall surface 5c rising vertically from the waveguide module mounting surface 5d, and a light emitting element module mounting surface 5a falling vertically from the waveguide module mounting surface 5d. One or a plurality of relief grooves 6 are formed in the waveguide module mounting surface 5d.

  The waveguide module 2 is bonded to the waveguide module mounting surface 5d with an adhesive (not shown). The escape groove 6 is provided to prevent the waveguide module 2 from being lifted or inclined with respect to the waveguide module mounting surface 5d by causing excess adhesive to escape during the bonding. Further, the escape groove 6 can prevent excessive adhesive from adhering to the end face of the branch core 3.

  The light emitting element module 1 is a can type light emitting element module in which a light emitting element (not shown) is accommodated in a metal cylindrical housing. In the light emitting element module 1, an optical axis passes through one end surface of the casing, and the periphery of the optical axis is an edge 1a of the casing. The cylindrical case of the light emitting element module 1 is welded and fixed to the base 5 by contacting the edge 1a of the light emitting element module 1 with the light emitting element module mounting surface 5a of the base 5 and welding the joint surface with a YAG laser. ing. However, in FIG. 3, the light emitting element module 1 and the base 5 are drawn apart for the sake of explanation.

  In a state where the light emitting element module 1 and the base 5 are joined, the optical axis of the light emitting element module 1 is at the position of the alternate long and short dash line C, and each branch core 3 (see FIGS. 1 and 2) in the waveguide module 2 is also It is at the position of the alternate long and short dash line C.

  A plurality of drive circuits 6 for driving the light emitting elements of the four light emitting element modules 1 are mounted on one substrate 7. This board 7 is called a drive circuit board. The drive circuit board 7 is a rigid board with low flexibility. On the other hand, the four light emitting element modules 1 are mounted on another substrate 8. This substrate 8 is called a light emitting element substrate. The light emitting element substrate 8 is a rigid substrate with low flexibility. The light emitting element substrate 8 and the drive circuit substrate 7 are coupled to a common flexible substrate 9. The flexible substrate 9 is a highly flexible substrate and can be bent freely.

  The drive circuit board 7 is attached to the upper surface 2 e of the waveguide module 2. However, in FIG. 3, the flexible substrate 9 and the waveguide module 2 are illustrated separately for the sake of explanation. On the other hand, since the light emitting element module 1 is joined to the light emitting element module mounting surface 5a of the base 5, the portion of the flexible substrate 9 on which the light emitting element substrate 8 is mounted faces the light emitting element module mounting surface 5a of the base 5. It is out. The flexible substrate 9 is curved in a curved manner between the light emitting element substrate 8 and the drive circuit substrate 7.

  1A and 1B show a main circuit board 10. The main circuit board 10 is obtained by mounting a main circuit (not shown) for controlling the drive circuit 6 on one rigid board. The main circuit board 10 is also coupled to the flexible board 9. The flexible board 9 can be appropriately bent between the drive circuit board 7 and the main circuit board 10.

  Hereinafter, the function and effect of the present invention will be described.

The waveguide module 2 shown in FIG. 2 only needs to have a bending radius R of one place between the end face 2a and the end face 2c facing the end face 2a, and the spacing between the branch cores 3 is also bent. It suffices if the radius R can secure one space. The total number of bending points is four. On the other hand, in the waveguide module of FIG. 8 according to the background art, since the two cores are bent and assembled in the middle, it is necessary to secure a space corresponding to a plurality of bending radii R in both the vertical and horizontal directions. . The total number of bending points is as many as twelve. Due to this difference, the waveguide module 2 of the present invention can be reduced in size in both the vertical and horizontal directions. According to the trial calculation, the surface area = 250 mm ^{2 when the} waveguide module as an equivalent multiplexing member is realized by the background art, whereas the surface area = 156 mm ² is sufficient when realized by the present invention. From the above, in the present invention, by using the waveguide module 2 as shown in FIG. 2, the wavelength division multiplexing optical transmission module can be downsized.

  FIG. 4 shows a waveguide module according to another embodiment of the present invention.

  In the waveguide module 42, the end portions of the four branch cores 43 are disposed on the end surface 42a. Each branch core 43 extends at a right angle from the end surface 42a, is bent by about 90 ° in the direction of the end surface 42b with a bending radius R, and further extends toward the end surface 42b. The branch line core 43 adjacent to the portion where the branch line core 43 furthest from the end face 42b extends toward the end face 42b is gathered close to the bend radius R. The other two branch line cores 43 are also assembled in the same manner. The assembled cores are assembled to form one trunk core 44.

  In this embodiment, the branch cores 3 are not sequentially grouped into one trunk core 4 one by one as shown in FIG. 2, but a set of two branch cores 43 are gathered. Since the bending direction of the core 43 is uniform and the number of bendings is small, it can be made smaller than the waveguide module of FIG.

  FIG. 5 shows a waveguide module according to another embodiment of the present invention.

  In this waveguide module 52, the end portions of the two branch line cores 53 are disposed on the end surface 52a, and the end portions of the remaining two branch line cores 53 are disposed on the opposing end surface 52c. A branch core 53 extending perpendicularly from the end face 52a and the end face 52c is bent and gathered at a bending radius R in the direction of the end face 42b by about 90 °. The adjacent branch line cores 53 are also assembled in the same manner, thereby forming one trunk core 54.

  Also in this embodiment, the bending directions of the branch cores 43 are aligned and the number of bendings is small, so that the size can be reduced as compared with the waveguide module of FIG.

  In the above description, since the number of wavelength multiplexing is set to 4, the number of branch cores 3 (43, 53) is also set to 4. However, the present invention is not limited to this, and the number of branch cores is set to the number of wavelength multiplexing. It can be arbitrarily combined.

  In the present invention, the waveguide module 2 is attached to the metal base 5, and the can-type light emitting element module 1 is attached to the base 5. Since joining of the base 5 and the light emitting element module 1 is metal, it can be easily performed by laser welding. Moreover, since the edge 1a of the housing | casing of the light emitting element module 1 is flat, it can contact | abut to the light emitting element module attachment surface 5a of the base 5 easily, and optical axis alignment is also easy.

  Furthermore, in the present invention, as shown in FIG. 3, since the relief groove 6 is provided in the waveguide module mounting surface 5d of the base 5, an excess adhesive is used when the waveguide module 2 is bonded with an adhesive. Can escape. Thereby, it is possible to prevent the waveguide module 2 from being lifted or tilted by the surplus adhesive and to prevent the surplus adhesive from adhering to the end face of the branch core 3. Further, when the thickness of the adhesive is thick, the adhesive strength is lowered, but by releasing excess adhesive, the thickness of the adhesive can be reduced and the adhesive strength can be increased.

  As shown in FIG. 6, the waveguide module 2 is obtained by laminating a waveguide substrate 62 made of silicon resin or glass on a substrate 61 made of acrylic resin. The cores 3 and 4 shown in FIG. 2 are formed in the waveguide substrate 62. On the other hand, the base 5 is made of, for example, stainless steel (SUS). An adhesive layer 63 is formed between the base 5 and the substrate 61. According to this structure, when the base 5 is thermally expanded, the stress generated in the core can be relaxed.

  In the present invention, the drive circuit board 7 is arranged on the upper surface 2e of the waveguide module 2 as shown in FIG. Furthermore, since the drive circuit board 7 and the light emitting element board 8 are mounted on the flexible board 9, wiring by cables or the like can be reduced. Furthermore, the wiring can be further reduced by mounting the main circuit board 10 on the flexible board 9. In addition, by using a rigid flexible substrate for manufacturing the substrates 7, 8, 9 or the substrates 7, 8, 9, 10 at a time, the substrates 7, 8, 9 or the substrates 7, 8, 9, 10 are connected to each other. This eliminates the need for connecting parts such as connectors and terminals, and enables further miniaturization and integration.

  When the waveguide module 52 of FIG. 5 is used, the light emitting element substrate 8 may be divided into two pieces and mounted on the flexible substrate 9 respectively.

  FIG. 7 shows another embodiment relating to the mounting of the drive circuit board 7.

  As shown in FIG. 7, a heat radiation sheet 71 having high thermal conductivity is sandwiched between the drive circuit board 7 and the waveguide module 2. A part of the heat radiation sheet 71 is formed to be larger than the waveguide module 2, and the protruding portion is in contact with the light emitting element module 1 and the base 5. In FIG. 7, the waveguide module 2, the heat dissipation sheet 71, and the drive circuit board 7 are drawn apart from each other for the sake of explanation. Thereby, the heat generated in the drive circuit 6 and the heat generated in the light emitting element module 1 can be released to the base 5.

  In addition, a heat radiation and electromagnetic shielding sheet 72 having high thermal conductivity and high conductivity is provided on the upper portion of the drive circuit board 7. Thereby, the drive circuit 6 can be protected from electrical noise.

It is a figure of the wavelength division multiplexing optical transmission module which shows one embodiment of the present invention, (a) is a top view and (b) is a side view. It is a core structure figure of the waveguide module in FIG. It is sectional drawing of the wavelength division multiplexing optical transmission module of FIG. It is a core structure figure of the waveguide module which shows one embodiment of the present invention. It is a core structure figure of the waveguide module which shows one embodiment of the present invention. FIG. 4 is a detailed view of a waveguide module portion of FIG. 3. It is sectional drawing of the wavelength division multiplexing optical transmission module which shows one Embodiment of this invention. It is a core structure figure of the waveguide module of background art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element module 2 Waveguide module 3 Branch line core 4 Trunk core 5 Base 6 Drive circuit 7 Drive circuit board 8 Light emitting element board 9 Flexible board

Claims (5)

  In a wavelength multiplexing optical transmission module that multiplexes and emits light having different wavelengths from a plurality of light emitting elements, the plurality of light emitting elements are arranged side by side so that their optical axes are parallel to each other, and the light emitting elements are formed in a rectangular parallelepiped shape. One end face of the formed waveguide module is faced, and end portions of a plurality of cores (hereinafter referred to as branch line cores) that take in light of each light emitting element are disposed on the end face of the waveguide module. A wavelength in which one core (hereinafter referred to as a trunk line core) in which the plurality of branch line cores are assembled is formed, and an end of the trunk core is disposed on another end face orthogonal to the end face Multiplex optical transmission module.   2. The waveguide module according to claim 1, wherein a bottom surface of the waveguide module is attached to a metal base, each of the plurality of light emitting elements is housed in a metal cylindrical housing, and the cylindrical housing is fixed to the base by welding. 2. The wavelength division multiplexing optical transmission module according to 1.   3. The wavelength division multiplexing optical transmission module according to claim 2, wherein the waveguide module is bonded to the metal base with an adhesive, and a relief groove for the adhesive is formed in the metal base.   A plurality of driving circuits for driving each of the plurality of light emitting elements are mounted on one substrate to form a driving circuit substrate, and the plurality of light emitting elements are mounted on another one substrate to form a light emitting element substrate. 4. The wavelength division multiplexing optical transmission module according to claim 1, wherein the driving circuit board is coupled to a common flexible board and the driving circuit board is attached to an upper surface of the waveguide module. 5. The main circuit for controlling the driving circuit is further mounted on another board to form a main circuit board, and the main circuit board and the driving circuit board are coupled to a common flexible board. The wavelength division multiplexing optical transmission module described.

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