JP2009099587A - Optical transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmitter allowing two types of laser diode modules having different shapes to be mounted on housings having the same shape. <P>SOLUTION: A coaxial type laser unit 30 is composed by mounting a coaxial type LDM 11 to an L-shaped mounting member 31 to set the position of each signal pin 15 at a predetermined height. A butterfly type laser unit 50 is composed by mounting a butterfly type LDM 21 on a flat mounting member 51 to set each signal pin 25 at the predetermined height. That is to say, the coaxial type LDM 11 and the butterfly type LDM 21 are composed to be mounted on the housings having the same shape by making the height of the signal pins 15 in the coaxial laser unit 30 and that of the signal pins 25 in the butterfly type laser unit 50 uniform. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical transmitter in which two types of laser diode modules having different shapes can be mounted in a housing having the same shape.

  Conventionally, in an optical transmitter used in a CATV (Cable Television) system or the like, a laser diode is used as an optical signal generating element (see, for example, Patent Document 1).

  The laser diode is roughly divided into a relatively inexpensive coaxial laser diode module (LDM) 11 shown in FIG. 9A and a high-precision butterfly laser diode module (LDM) 21 shown in FIG. These two types are conventionally used. FIG. 9A is a perspective view showing the external configuration of the coaxial LDM 11, and FIG. 9B is a perspective view showing the external configuration of the butterfly LDM 21.

  As shown in FIG. 9A, the coaxial LDM 11 generates a laser comprising a laser diode chip, a lens, an isolator, etc. that converts an analog high-frequency signal into an optical signal and outputs it in a cylindrical case 12 as shown in FIG. The part is stored. A mounting bracket 13 is attached to one end of the cylindrical case 12, and an optical fiber 14 for outputting an optical signal is provided on the other end side. The cylindrical case 12 is formed in a tapered shape so that the lead-out side of the optical fiber 14 becomes thin. In addition, the mounting bracket 13 is provided with a hole 16 through which a plurality of signal pins 15 are inserted in the central portion, and screw insertion holes 17a and 17b in the vicinity of both ends. The signal pin 15 is for inputting a high-frequency signal, a control signal, or the like to the laser generator.

  Further, as shown in FIG. 9B, the butterfly type LDM 21 is a laser generating unit comprising, for example, a laser diode chip, a lens, an isolator, etc., which converts an analog high frequency signal into an optical signal and outputs it in a box-like case 22. Is stored. A cylindrical portion 23 is connected to the rear end side of the box-shaped case 22, and an optical fiber 24 that outputs an optical signal is provided in the cylindrical portion 23. The cylindrical portion 23 is formed in a tapered shape so that the lead-out side of the optical fiber 24 is thin. A plurality of signal pins 25 are provided on the left and right sides of the long side of the box-like case 22. The plurality of signal pins 25 are provided with a terminal for inputting a high frequency signal, a control signal, and the like to the laser generator, and a ground terminal. Further, a plurality of, for example, two screwing portions 26 are provided on the outside of the box-like case 22 so as to protrude laterally so as to be positioned at opposing angles. The screwing portions 26 are for fixing the butterfly-type LDM 21 to the housing, and there are four provided.

  As described above, since the coaxial LDM 11 and the butterfly LDM 21 are greatly different in shape, conventionally, the structure of the housing to be mounted is changed depending on which of the coaxial LDM 11 and the butterfly LDM 21 is used.

  10A and 10B show a configuration example of a housing on which the butterfly-type LDM 21 is mounted, in which FIG. 10A is a plan view showing the lid provided on the upper surface opening, and FIG. 10B is a side sectional view.

  In FIG. 10, reference numeral 100 denotes a metal case, for example, an aluminum die-cast housing. The upper surface is opened, and the center portion of the outer surface of the bottom 101 is recessed upward to constitute the radiating fin mounting portion 102. Although not shown in the figure, a heat radiation fin is attached to the heat radiation fin mounting portion 102.

  Further, the bottom portion 101 of the casing 100 forms a laser unit mounting portion 104 having a predetermined height by forming a part thereof thickly at a portion where the radiating fin mounting portion 102 is formed. A plurality of support members 105 having a predetermined height are provided on both sides of the upper surface of the bottom portion 101 at a predetermined interval, and the circuit board 106 is placed on the support member 105 and fixed with screws 107.

  The circuit board 106 is provided with a notch 108 at a portion corresponding to the laser unit mounting portion 104 and a portion corresponding to the cylindrical portion of the laser unit so that the butterfly type LDM 21 can be mounted on the laser unit mounting portion 104. Further, the housing 100 is equipped with a light output connector 109 for outputting laser light to the outside, for example, on the front side.

  The butterfly LDM 21 is fixed on the laser unit mounting portion 104 with screws 110a and 110b, and the signal pins 25 of the butterfly LDM 21 are connected to a predetermined circuit portion formed on the circuit board 106, and the butterfly LDM 21 Is connected to the optical output connector 109.

  After the butterfly LDM 21 is mounted on the housing 100, the lid 111 is attached to the upper opening of the housing 100 by screws or the like.

  As described above, the housing 100 has the height of the laser unit mounting portion 104 so that the height of the signal pin 25 of the butterfly LDM 21 mounted on the laser unit mounting portion 104 is at an appropriate position with respect to the circuit board 106. Is set. The circuit board 106 forms a circuit pattern corresponding to the signal pin 25 of the butterfly type LDM 21.

On the other hand, the coaxial LDM 11 is different in the arrangement and direction of the signal pins 15 from the signal pins 25 of the butterfly LDM 21 and has a different mounting structure to the casing. And the structure of the laser unit mounting portion is different. Further, the coaxial LDM 11 is different from the butterfly LDM 21 in the arrangement and direction of signal pins. Therefore, the same circuit board as the butterfly LDM 21 cannot be used, and a dedicated circuit board is used.
JP 2006-74193 A

  In an optical transmitter, generally, two types of laser diodes, a coaxial LDM11 and a butterfly LDM21, are selectively used depending on the model, but the arrangement and direction of signal pins differ between the coaxial LDM11 and the butterfly LDM21 as described above. For this reason, it is not possible to use the same-shaped casing, and each uses a dedicated casing and a dedicated circuit board. For this reason, the number of parts increases, there is a problem that parts management is troublesome and cost is high.

  The present invention has been made to solve the above problems, and an object thereof is to provide an optical transmitter capable of mounting a coaxial laser diode module or a butterfly laser diode module in a casing having the same shape. .

  An optical transmitter according to a first invention comprises a coaxial laser diode module or a butterfly laser diode module, a circuit board on which the laser diode module is mounted, and a housing in which the circuit board is mounted. In the optical transmitter, each case is mounted with any type of laser diode module via a dedicated mounting member, and the signal pins have the same height, and the signal pins are mounted in the case. The circuit board is configured to be held at a position where wiring is possible with respect to the circuit board.

  According to a second aspect of the present invention, in the optical transmitter according to the first aspect of the present invention, the circuit board is preliminarily wired with a circuit pattern so as to be compatible with any type of the laser diode module. Corresponding circuit patterns can be selected by changing the incorporation of parts accordingly.

  According to the present invention, the coaxial laser diode module and the butterfly laser diode module are mounted on the optical transmitter casing via the dedicated mounting members so that the signal pins have the same height. It is possible to use the same casing for different coaxial laser diode modules and butterfly laser diode modules.

  In addition, the circuit pattern is wired on the circuit board so that it can correspond to either the coaxial type laser diode module or the butterfly type laser diode module, and the integration of the parts is changed depending on which laser diode is used, thereby making the same It is possible to deal with both laser diodes with this substrate.

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

  FIG. 1 is a diagram for explaining an outline of a laser diode mounting method in an optical transmitter according to an embodiment of the present invention. FIG. 1A is a perspective view of a coaxial laser unit 30 using a coaxial LDM 11. FIG. 1B is a perspective view of a butterfly type laser unit 50 using the butterfly type LDM 21.

  As shown in FIG. 1A, the coaxial laser unit 30 is configured such that the coaxial LDM 11 is attached to an L-shaped attachment member 31 so that the signal pin 15 is positioned at a predetermined height.

  Further, the butterfly type laser unit 50 is configured so that the butterfly type LDM 21 is mounted on the flat plate type mounting member 51 and the position of the signal pin 25 becomes a predetermined height as shown in FIG.

  By aligning the height of the signal pin 15 in the coaxial laser unit 30 and the height of the signal pin 25 in the butterfly laser unit 50 as described above, the coaxial LDM 11 and the butterfly LDM 21 having different shapes can be obtained. It is configured so that it can be mounted in a casing of the same shape.

  Details of the coaxial laser unit 30 and the butterfly laser unit 50 will be described below.

  First, the configuration of the coaxial laser unit 30 will be described with reference to FIGS. 1 (a), 2 and 3. FIG.

  2A and 2B show a configuration of the coaxial laser unit 30. FIG. 2A is a plan view, FIG. 2B is a side view, FIG. 3C is a front view, and FIG.

  Since the coaxial LDM 11 is the same as that shown in FIG. 9A, the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  The coaxial laser unit 30 is configured so that the coaxial LDM 11 is mounted on an L-shaped mounting member 31 and the position of the signal pin 15 is at a predetermined height, as shown in FIGS. To do. The L-shaped attachment member 31 is formed by bending a square metal plate into an L-shape, and fixed holes 32a and 32b are provided on both the left and right sides of the bottom 31a for mounting on the housing. Further, the front rising portion 31 b of the L-shaped attachment member 31 is provided with a substantially U-shaped notch 33 at the center upper portion, and screw holes 34 a and 34 b on both sides of the notch 33. The screw holes 34a and 34b are provided corresponding to the screw insertion holes 17a and 17b provided in the mounting bracket 13 of the coaxial LDM 11. In addition, a thermistor mounting hole 35 is provided below the one screw hole 34 a in the front rising portion 31 b, and the thermistor 36 is inserted into the thermistor mounting hole 35.

  A substrate 38 is provided on the front side of the front rising portion 31b via a ground metal fitting 37. The substrate 38 is configured using an insulating material such as synthetic resin. The ground metal fitting 37 is formed to be approximately the same size as the attachment metal fitting 13 of the coaxial LDM 11, and is provided with a hole 39 through which the signal pin 15 of the coaxial LDM 11 is inserted at the center, and screw insertion holes 41a on both sides thereof. , 41b are provided. The screw insertion holes 41 a and 41 b are provided at positions corresponding to the screw holes 34 a and 34 b provided in the front surface rising portion 31 b of the L-shaped attachment member 31. In addition, ground protrusions 42 a and 42 b are provided on the left and right side portions of the ground metal fitting 37 so as to protrude forward by a predetermined length.

  Further, the board 38 is provided with a connector 43 at the upper front portion and screw insertion holes 44a and 44b on the left and right sides. The screw insertion holes 44 a and 44 b are provided at positions corresponding to the screw insertion holes 41 a and 41 b of the ground metal fitting 37. Further, the board 38 is provided with holes 45a and 45b through which the ground protrusions 42a and 42b of the ground metal fitting 37 are inserted outside the screw insertion holes 44a and 44b. A connection terminal provided in the connector 43 is connected to a predetermined signal pin 15 of the coaxial LDM 11 through a circuit pattern formed on the substrate 38.

  Further, the board 38 is provided with a plurality of holes for inserting the signal pins 15 of the coaxial LDM 11 below the connector 43, and the lead wire 36a of the thermistor 36 is inserted below the screw insertion hole 44a. A lead wire insertion hole 47 is provided.

  Then, the case front end portion of the coaxial LDM 11 is placed in the notch 33 portion provided in the front surface rising portion 31b of the L-shaped mounting member 31, and the mounting bracket 13 is positioned outside the front surface rising portion 31b. The board 38 is positioned through the ground metal fitting 37 so as to face the mounting metal 13, and screws 48a and 48b are inserted into the screw insertion holes 44a and 44b provided in the board 38 from the front side, and the screws 48a and 48b. The front end of the L-shaped mounting member 31 is provided at the front rising portion 31b via the screw insertion holes 17a and 17b provided in the mounting holes 13 of the grounding metal 37 and the mounting holes 13 of the coaxial LDM 11. The coaxial laser unit 30 is configured by screwing into the screw holes 34 a and 34 b and fixing the coaxial LDM 11, the ground metal fitting 37 and the substrate 38 to the L-shaped attachment member 31. In this case, the signal pin 15 of the coaxial LDM 11 is led out from the hole provided in the substrate 38 through the hole 39 of the ground metal fitting 37. Further, the thermistor 36 is mounted in the thermistor mounting hole 35 provided in the front rising portion 31 b of the L-shaped attachment member 31, and the lead wire is led out from the lead wire insertion hole 47 provided in the substrate 38.

  The coaxial laser unit 30 configured as described above is mounted on the housing 60 shown in FIG.

  4A and 4B show a state where the coaxial laser unit 30 is mounted on the housing 60 of the optical transmitter. FIG. 4A is a plan view with the lid provided on the upper surface opening removed, and FIG. is there.

  The housing 60 is made of metal, for example, aluminum die-casting. The upper surface is opened, and the central portion of the outer surface of the bottom 61 is recessed inward, that is, upward, to form a heat radiation fin mounting portion 62. Although not shown in the drawing, a radiation fin is mounted on the radiation fin mounting portion 62.

  Further, the bottom 61 of the housing 60 forms a laser unit mounting portion 64 having a predetermined height by, for example, denting the vicinity of the front end side downward at a portion where the heat radiating fin mounting portion 62 is formed. A plurality of support members 65 having a predetermined height are provided on the top surface of the bottom portion 61 along the side portions at predetermined intervals, and the circuit board 66 is placed on the support member 65 and fixed with screws 67.

  The circuit board 66 is provided with a notch 68 at a portion corresponding to the laser unit mounting portion 64 and a portion corresponding to the cylindrical portion of the laser unit so that the coaxial laser unit 30 can be mounted on the laser unit mounting portion 64. Yes. Further, the housing 60 is equipped with, for example, a light output connector 69 for outputting laser light to the outside on the front side. This optical output connector 69 is connected in advance to the optical fiber 14 led out from the coaxial LDM 11.

  A lid 71 is attached to the upper opening of the housing 60 by screws or the like.

  When the coaxial laser unit 30 is mounted on the housing 60, the coaxial laser unit 30 is fixed on the laser unit mounting portion 64 with screws 70a and 70b, and the signal pins 15 of the coaxial LDM 11 are formed on the circuit board 66. Connected to a predetermined circuit. A connector (not shown) connected to the circuit board 66 is attached to the connector 43 of the coaxial LDM 11.

  The coaxial laser unit 30 mounted on the laser unit mounting portion 64 is arranged so that the height of the signal pin 15 of the coaxial LDM 11 is at an appropriate position with respect to the circuit board 66, that is, the signal pin 15 is connected to the circuit. The mounting position of the coaxial LDM 11 with respect to the L-shaped attachment member 31 is set in advance so that it can be connected to the circuit pattern of the substrate 66.

  Next, the configuration of the butterfly laser unit 50 will be described with reference to FIGS. 1B, 5 and 6. FIG.

  FIG. 5 shows an external configuration of the butterfly type laser unit 50, (a) is a plan view, (b) is a side view, (c) is a front view, and FIG. 6 is an exploded perspective view of the butterfly type laser unit 50.

  Since the butterfly type LDM 21 is the same as that shown in FIG. 9B, the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  In the butterfly type laser unit 50, as shown in FIGS. 1B, 5 and 6, the butterfly type LDM 21 is mounted on the flat plate type mounting member 51 so that the position of the signal pin 25 becomes a predetermined height. Constitute. In this case, the height of the signal pin 25 is adjusted by the thickness of the flat plate mounting member 51.

  The flat plate mounting member 51 is provided with fixing through holes 52a and 52b in the vicinity of both sides, and screw holes 53a and 53b are provided at positions corresponding to the screwing portions 26 of the butterfly LDM 21. In the butterfly type LDM 21, the screwing portion 26 is fixed to the screw holes 53 a and 53 b of the flat plate type mounting member 51 by screws 54 a and 54 b.

  The butterfly type laser unit 50 configured as described above is mounted on the housing 60 shown in FIGS. 7 (a) and 7 (b).

  FIG. 7 shows a state in which the butterfly laser unit 50 is mounted on the housing 60 of the optical transmitter. FIG. 7A is a plan view showing the lid provided on the top opening, and FIG. 7B is a side sectional view. is there. Since the housing 60 is the same as that shown in FIG. 4, the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  When the butterfly laser unit 50 is mounted on the housing 60, first, the flat plate mounting member 51 is fixed to the laser unit mounting portion 64 with screws 70a and 70b. Next, the butterfly type LDM 21 is placed on the flat plate mounting member 51, and the screwing portions 26 provided in the box-shaped case 22 are aligned with the screw holes 53 a and 53 b provided in the flat plate mounting member 51. It is fixed with screws 54a and 54b.

  Then, the signal pin 25 of the butterfly LDM 21 is connected to a predetermined circuit portion formed on the circuit board 66. The optical fiber 24 led out from the butterfly LDM 21 is connected in advance to the optical output connector 69.

  The butterfly type laser unit 50 mounted on the laser unit mounting portion 64 has a thickness of the flat plate mounting member 51 such that the height of the signal pin 25 of the butterfly type LDM 21 is at an appropriate position with respect to the circuit board 66. Is preset.

  As shown in the above embodiment, by aligning the height of the signal pin 15 in the coaxial laser unit 30 and the height of the signal pin 25 in the butterfly laser unit 50 to be the same, The same housing 60 can be used with the butterfly LDM 21.

  The circuit board 66 to be mounted on the housing 60 may be a dedicated board for the coaxial LDM 11 and the butterfly LDM 21, respectively, but may be compatible with both the coaxial LDM 11 and the butterfly LDM 21. It is possible to cope with both laser diodes on the same substrate by wiring the circuit pattern and changing the incorporation of components depending on which laser diode is used.

  For example, as shown in FIG. 8, on the circuit board 66, a first signal path 81 is provided between the high-frequency signal input terminal 80 and the high-frequency signal input signal pin 15a of the coaxial LDM 11, and the high-frequency signal input terminal 80 and A second signal path 91 is provided between the butterfly LDM 21 and the high frequency signal input signal pin 25a.

  In the first signal path 81, jumper wire connection terminals 82a and 82b and an impedance matching unit 83 are provided in series. The second signal path 91 is provided with jumper line connection terminals 92a and 92b and an impedance matching device 93 in series.

  When the coaxial type LDM 11 is used, the jumper line 84 is connected between the jumper line connection terminals 82a and 82b of the first signal path 81. When the butterfly type LDM 21 is used, the jumper line of the second signal path 91 is used. A jumper wire 94 is connected between the connection terminals 92a and 92b.

  As described above, when the jumper wire 84 is connected between the jumper wire connection terminals 82a and 82b of the first signal path 81, the high frequency signal input to the high frequency signal input terminal 80 passes through the jumper wire 84 and the impedance matching unit 83. To the high frequency signal input signal pin 15a of the coaxial LDM11.

  Further, when the jumper wire 94 is connected between the jumper wire connection terminals 92 a and 92 b of the second signal path 91, the high frequency signal input to the high frequency signal input terminal 80 passes through the jumper wire 94 and the impedance matching device 93. The signal is sent to the high frequency signal input signal pin 15a of the coaxial LDM11.

  By selectively using the jumper wires 84 and 94 as described above, a high frequency signal can be input to the high frequency signal input signal pin 15a of the coaxial LDM 11 or the high frequency signal input signal pin 25a of the butterfly type LDM 21. The substrate 66 can be used in common for the coaxial LDM 11 and the butterfly LDM 21.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the outline of the mounting method of the laser diode in the optical transmitter which concerns on one Embodiment of this invention, (a) is a perspective view of the coaxial laser unit using coaxial LDM, (b) is a butterfly It is a perspective view of a butterfly type laser unit using a type LDM. The structure of the coaxial laser unit in the embodiment is shown, (a) is a plan view, (b) is a side view, and (c) is a front view. It is a disassembled perspective view of the coaxial laser unit in the same embodiment. The coaxial type laser unit in the same embodiment is shown mounted on the housing of the optical transmitter, (a) is a plan view showing the cover provided on the top opening, and (b) is a side sectional view. . The external appearance structure of the butterfly type laser unit in the embodiment is shown, (a) is a plan view, (b) is a side view, and (c) is a front view. It is a disassembled perspective view of the butterfly type laser unit in the same embodiment. The state which mounted the butterfly type laser unit in the embodiment in the housing | casing of the optical transmitter is shown, (a) is a top view which removes the cover body provided in an upper surface opening part, (b) is a sectional side view. In the embodiment, it is a figure which shows the example of schematic structure of the principal part of the circuit board which shared the coaxial type LDM and the butterfly type LDM. (A) is a perspective view which shows the external appearance structure of a coaxial type LDM, (b) is a perspective view which shows the external structure of a butterfly type LDM. The structural example of the conventional housing | casing which mounts a butterfly type LDM is shown, (a) is a top view which removes and shows the cover body provided in an upper surface opening part, (b) is a sectional side view.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Coaxial LDM (laser diode module), 12 ... Cylindrical case, 13 ... Mounting bracket, 14 ... Optical fiber, 15, 15a ... Signal pin, 16 ... Signal pin insertion hole, 17a, 17b ... Screw insertion hole 21 ... Butterfly type LDM (laser diode module), 22 ... Box-shaped case, 23 ... Cylindrical part, 24 ... Optical fiber, 25, 25a ... Signal pin, 30 ... Coaxial laser unit, 31 ... L-shaped mounting member 32a, 32b ... Fixing holes, 34a, 34b ... Screw holes, 35 ... Thermistor mounting holes, 36 ... Thermistor, 37 ... Ground metal fittings, 38 ... Substrate, 39 ... Signal pin insertion holes, 41a, 41b ... Screw insertion holes 42a, 42b ... ground projection, 43 ... connector, 44a, 44b ... screw insertion hole, 45a, 45b ... ground projection insertion hole, 47 ... thermistor lead Line insertion hole, 48a, 48b ... screw, 50 ... butterfly type laser unit, 51 ... flat plate mounting member, 52a, 52b ... fixing through hole, 53a, 53b ... screw hole, 54a, 54b ... screw, 60 ... housing , 61 ... Bottom, 62 ... Radiation fin mounting part, 64 ... Laser unit mounting part, 65 ... Support member, 66 ... Circuit board, 67 ... Screw, 69 ... Optical output connector, 70a, 70b ... Screw, 71 ... Lid 80 ... high frequency signal input terminal, 81 ... first signal path, 82a, 82b ... jumper wire connection terminal, 83 ... impedance matching unit, 84 ... jumper wire, 91 ... second signal route, 92a, 92b ... jumper wire Connection terminal, 93 ... impedance matching device, 94 ... jumper wire.

Claims (2)

  In an optical transmitter comprising a coaxial type laser diode module or a butterfly type laser diode module, a circuit board on which the laser diode module is mounted, and a case in which the circuit board is mounted, each case is dedicated No matter which type of laser diode module is mounted via the mounting member, the signal pins have the same height and can be wired to the circuit board mounted in the housing. An optical transmitter characterized in that the optical transmitter is held so that   The circuit board has a circuit pattern wired in advance so as to be compatible with any type of laser diode module, and the corresponding circuit pattern can be selected by changing the incorporation of components according to the laser diode module to be mounted. The optical transmitter according to claim 1.

Images