JP4914775B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module used for optical communication.

  In recent years, as an optical communication system is increased in speed and capacity, optical modules such as an optical transmitter and an optical receiver used for optical communication are required to be small in size and have high-speed operation characteristics. In order to meet this requirement, an optical module in which a driving IC for driving a semiconductor laser element is built in a housing is disclosed (for example, see Patent Document 1). In this optical module, a high-frequency characteristic is ensured and the entire size including the optical module and the drive circuit is reduced by incorporating the drive IC in the housing.

  On the other hand, for example, an optical module for complying with the XFP (10 Gigabit Small Form Factor Pluggable) standard is particularly demanded for high speed (several tens of gigabits per second) and miniaturization. For example, in an optical transmitter disclosed in Patent Document 2, a laser and a drive driver are wired via a wiring pattern formed on the substrate up to the vicinity of the laser, and wire connection is performed in the vicinity of the laser, thereby mounting the drive driver. While being built in the body, it has been downsized to meet the XFP standard.

JP 2003-264331 A JP 2005-82261 A

  However, the conventional optical module includes a plurality of substrates for performing electrical wiring and uses these substrates side by side, so that a gap is formed between the substrates and it is difficult to reduce the size. There was a problem. Further, since there is a gap between the substrates, it is necessary to wire between the substrates, so that there is a problem that the high-frequency characteristics deteriorate due to the wire wiring.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical module that is compact and has good high-frequency characteristics.

  In order to solve the above-described problems and achieve the object, an optical module according to the present invention includes a housing, an optical device that emits or receives laser light in the housing, and a position adjacent to the optical device. Are arranged so as to extend to the outside of the housing, and are arranged in a region on the inside of the substrate on which a wiring pattern is formed, and transmit or receive high-frequency signals between the optical device and the outside An electronic device, and in an assembled state, a lead terminal is provided in a portion of the wiring pattern that extends to the outside of the housing.

  The optical module according to the present invention is characterized in that, in the above invention, the substrate is formed by stacking a plurality of substrates.

  In the optical module according to the present invention, in the above invention, the casing is formed by laminating a plurality of casing constituent members made of ceramic, and the substrate is made of ceramic, and the plurality of casings. It is characterized by being laminated between body constituent members and integrated with the plurality of casing constituent members to constitute a multilayer ceramic structure.

  The optical module according to the present invention is characterized in that, in the above-mentioned invention, the optical device is a laser light emitting means, and the electronic device is a driver for driving and controlling the laser light emitting means.

  In the optical module according to the present invention, the optical device is a light receiving unit that receives laser light and converts it into an electrical signal, and the electronic device is an amplification unit that amplifies the converted electrical signal. It is characterized by being.

  According to the present invention, since an unnecessary gap between the substrates does not occur in the housing and no wire wiring for connecting the substrates is required, an optical module that is small in size and has good high frequency characteristics can be obtained. There is an effect that it can be realized.

  Embodiments of an optical module and an optical module manufacturing method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
First, the optical module according to the present embodiment will be described. The optical module according to the present embodiment is an optical transmitter that emits laser signal light. 1 to 4 are schematic views schematically showing the optical module according to the present embodiment, FIG. 1 is a schematic plan view, FIG. 2 is a schematic side sectional view, FIG. 3 is a schematic perspective sectional view, and FIG. FIG. In addition, in each of FIGS. 1-4, description of a one part structure is abbreviate | omitted for description.

  As shown in FIGS. 1 to 4, the optical module 100 includes a housing 1. The casing 1 includes a base 11, a lower casing constituent member 12 having a multilayer structure, a multilayer substrate 2, an upper casing constituent member 13 having a multilayer structure, a seal ring 14, and a lid portion 15. Prepare. Further, the lower casing constituent member 12, the upper casing constituent member 13 and the multilayer substrate 2 are laminated and integrated to form a multilayer ceramic structure. Further, a part of the multilayer substrate 2 extends to the outside of the housing 1.

  The base 11 has a rectangular parallelepiped plate shape and is made of a material having high thermal conductivity such as copper tungsten. The lower casing component member 12, the upper casing component member 13, and the multilayer substrate 2 are disposed on the base 11. The lower casing constituent member 12, the upper casing constituent member 13, and the multilayer substrate 2 are made of an insulating ceramic material such as alumina and are integrated to constitute a multilayer ceramic structure. A wiring pattern 2 a is formed on the multilayer substrate 2, and a part thereof extends to the outside of the housing 1. The multilayer substrate 2 is made of an insulating ceramic material such as alumina and is provided with a wiring pattern 2a having good high frequency characteristics.

  The seal ring 14 is a member for hermetically sealing the inside of the housing 1 by welding the lid portion 15. The seal ring 14 and the lid 15 are made of Kovar or the like having good weldability. The multilayer ceramic structure formed by the lower casing constituent member 12, the upper casing constituent member 13, and the multilayer substrate 2 is made of a ceramic material such as alumina, and thus has low thermal conductivity, and is externally provided in the casing 1 from the outside. It has the effect of preventing heat from flowing into.

  A hole is formed in the front surface portion of the multilayer ceramic structure. In this hole, a window pipe 6 containing a window 61 made of sapphire, glass or the like is fitted. Further, an optical fiber connecting pipe 7 made of Kovar or the like into which an optical fiber stub 8 is inserted and fixed is fitted in the window pipe 6. Is connected. The window pipe 6 is made of Kovar or the like for welding the optical fiber connection pipe 7 and is brazed with the multilayer ceramic structure to make the inside of the housing 1 airtight. 3 and 4, the description of the optical fiber connection pipe 7 and the optical fiber stub 8 is omitted.

  An assembly member 4 including a laser or the like is disposed in the space 3 formed by the lower casing constituent member 12 and the cutout portion of the multilayer substrate 2. The assembly member 4 includes an electronic cooling element 41 such as a Peltier element, support members 42a to 42c disposed on the electronic cooling element 41, a laser chip carrier 43 disposed on the support member 42b, a thermistor 45, and a monitor PD (Photo detector) 46, a semiconductor laser 44 disposed on the laser chip carrier 43, a lens holder 47 disposed on the support member 42c, and a lens 48 held by the lens holder 47. A wiring pattern 42ba is formed up to the vicinity of the semiconductor laser 44 on the support member 42b. A microstrip line is formed on the support member 42b and the laser chip carrier 43. In FIG. 3, the assembly member 4 is indicated by a broken line for explanation.

  In addition, an opening A is formed in the lower casing constituent member 12 and the multilayer substrate 2, and in the opening A, a heat sink 5a is disposed on the base 11, and the semiconductor laser 44 is disposed on the heat sink 5a. A drive driver 5 which is an integrated circuit for controlling the driving of the motor is mounted. The drive driver 5 is electrically connected to the wiring pattern 2a on the multilayer substrate 2 by a plurality of wires W1 and W2. Furthermore, the drive driver 5 is electrically connected to the semiconductor laser 44 via the wire W2, the wiring pattern 2a, the wire W3, the wiring pattern 42ba, the wire W4, and the microstrip line on the laser chip carrier 43. Note that each wiring pattern and microstrip line from the drive driver 5 to the semiconductor laser 44 are designed so that sufficient impedance matching is achieved, and sufficient high frequency characteristics are ensured.

  In addition, the multilayer substrate 2 is provided with a lead terminal L1 at a portion extending to the outside of the housing 1 of the wiring pattern 2a. As shown in FIG. 4, a metallized pattern 16 is formed on the side surface of the housing 1. The metallized pattern 16 is electrically connected to the wiring pattern 2 a formed on the multilayer substrate 2. The metallized pattern 16 is brazed with an L-shaped lead terminal L2. Since the housing 1 has a multilayer ceramic structure, the metallized pattern 16 can be formed on the side surface thereof, and the lead terminal L2 can be brazed to the metallized pattern 16 to reduce the size of the optical module 100. It is effective. In addition, since the multilayer ceramic structure is made of a highly insulating ceramic material, insulation between the wiring pattern 2a and the lead terminals L1 and L2 is ensured. The lead terminal L1 is electrically connected to the drive driver 5 via the wiring pattern 2a on the multilayer substrate 2 and the wire W1. The lead terminal L2 is electrically connected to the electronic cooling element 41, the semiconductor laser 44, the thermistor 45, or the monitor PD 46 via the wiring pattern 2a and the plurality of wires W5. In addition, in FIG. 3, description of the wires W1-W5 is abbreviate | omitted for description.

  In the optical module 100, a lead terminal L1 is provided at a portion of the wiring pattern 2a that extends to the outside of the housing 1. Therefore, the gap between the substrates, which is generated when the substrate on which the drive driver is disposed and the substrate for electrically connecting the drive driver to the outside of the optical module, is separated as in the related art It does not occur in module 100. In addition, wire wiring for connecting the substrates, which has been necessary in the past, is also unnecessary. As a result, the optical module 100 is small in size and has good high frequency characteristics. Further, the optical module 100 is further downsized because the gap between the multilayer substrate 2 and the housing 1 does not occur.

  Next, the operation of the optical module 100 will be described. The drive driver 5 is supplied with electric power and high-frequency electric signals from the outside via the lead terminals L1. The bit rate of this electric signal is, for example, 10 Gbps (10 G bit per second). The semiconductor laser 44 is supplied with electric power from the outside via the lead terminal L2 and is driven and controlled by being supplied with a high-frequency electric signal from the drive driver 5, and a laser light signal with a modulation frequency of 10 GHz is forwarded, that is, the lens 48 side. Output to. The optical signal output from the semiconductor laser 44 is converted into a parallel light beam by the lens 48, passes through the window 61, and then collected by the lens disposed inside the optical fiber connection tube 7 and outside the window pipe 6. Optically coupled to the fiber stub 8. The optical fiber stub 8 is connected to an optical fiber and transmits the optical signal output from the optical module 100 to the optical fiber.

  A part of the optical signal is also output behind the semiconductor laser 44, and the output optical signal is received by the monitor PD 46, and the monitor PD 46 outputs a current corresponding to the received light intensity. The output current is used for monitoring the output of the semiconductor laser 44. The semiconductor laser 44 generates heat during operation, but is cooled by the electronic cooling element 41 via the support members 42b and 42a. The temperature of the semiconductor laser 44 is monitored by a thermistor 45 disposed in the vicinity of the semiconductor laser 44, and the injection current to the electronic cooling element 41 is controlled so that the temperature of the semiconductor laser 44 becomes a predetermined temperature. Further, as described above, since the base 11 is made of a material having high thermal conductivity, heat dissipation from the electronic cooling element 41 to the base 11 is efficiently performed.

  If the support member 42b is made of a material having high thermal conductivity such as ceramic such as copper tungsten or aluminum nitride, the heat generated in the semiconductor laser 44 is efficiently transferred to the electronic cooling element 41 and cooled. It is preferable because efficiency is improved. In addition, if the support member 42c is made of a material having low thermal conductivity such as Kovar and has good weldability, the light emitted from the semiconductor laser 44 is coupled to the lens 48 to secure a stable optical path. The lens holder 47 can be fixed to the support member 42c by YAG laser welding or the like. As a result, even if the temperature of the lens holder 47 and the lens 48 rises due to heat generated from the semiconductor laser 44, the optical system may be displaced. Can be prevented.

  On the other hand, the drive driver 5 also generates heat during operation, but the generated heat is radiated from the base 11 via the heat sink 5a. The heat sink 5a is also preferably made of a material having high thermal conductivity such as copper tungsten, because the heat generated in the drive driver 5 is efficiently radiated.

  As described above, the optical module 100 according to the present embodiment is small in size because unnecessary gaps between the substrates do not occur in the housing and wire wiring for connecting the substrates is unnecessary. At the same time, the optical module has good high frequency characteristics.

  Next, an example of a method for manufacturing the optical module 100 will be described. 5 and 6 are explanatory views for explaining a method of manufacturing the optical module 100. FIG. 5 and 6 show schematic perspective sectional views similarly to FIG.

  First, as shown in FIG. 5, the assembly member 4 and the heat sink 5 a separately assembled are attached to predetermined positions on the base 11.

  Next, as shown in FIG. 6, a multilayer ceramic structure in which the lower casing constituent member 12, the upper casing constituent member 13 and the multilayer substrate 2 are integrated is laminated on the base 11. The window pipe 6 containing the seal ring 14 and the window 61 is previously brazed to the multilayer ceramic structure. Thereafter, lead terminals L1 and L2 are provided on the wiring pattern 2a of the multilayer substrate 2 and the metallization pattern 16 on the side surface of the housing 1.

  7 and 8 are schematic plan views schematically showing the uppermost substrate 21 and the second-layer substrate 22 from above among the substrates constituting the multilayer substrate 2. As shown in FIG. 7, the wiring pattern 2 a and the opening A <b> 1 are formed in the substrate 21, and further, a notch portion 21 b that forms a hole into which the window pipe 6 is fitted, and a notch portion 21 b are connected. A wide notch 21a that forms a space 3 in which the assembly member 4 is disposed is formed. Similarly, a wiring pattern 2b, an opening A2, and notches 22a and 22b are formed on the substrate 22. A plurality of via holes H1 and H2 are formed in the substrates 21 and 22, respectively, to enable electrical connection between the substrates. Note that wiring patterns and via holes are also formed on other substrates constituting the multilayer substrate 2. Thus, since the wiring pattern is formed on each substrate constituting the multilayer substrate 2 and each is electrically connected via the via hole, the substrate area is greatly reduced, and the optical module 100 is further reduced in size. Is realized.

  Next, the drive driver 5 is mounted on the heat sink 5a, and wires W1 to W5 are wired at predetermined positions. Further, after finely adjusting the position of the assembly member 4 so that the optical coupling between the semiconductor laser 44 and the optical fiber stub 8 is maximized, the lid portion 15 is welded onto the seal ring 14 and the inside of the housing 1 is hermetically sealed. Stop. Next, the optical fiber stub 8 is inserted into the optical fiber connection tube 7 and fixed, and the optical fiber connection tube 7 is attached to the window pipe 6 to complete the optical module 100.

  In the optical module 100, the lower casing constituent member 12, the upper casing constituent member 13, and the multilayer substrate 2 are integrated, but may be formed separately. Moreover, although what consists of ceramic materials was used as the lower housing | casing structural member 12, material is not specifically limited. Moreover, although the thing which consists of ceramic materials was used as the upper housing | casing structural member 13, if insulation between the wiring pattern 2a and the lead terminal L2 is ensured, material will not be specifically limited. For example, as the upper casing constituent member 13, only the lowermost layer member may be made of an insulating material, and the other layer members may be made of metal such as Kovar.

  Further, in the optical module 100, the lower casing constituent member 12 and the upper casing constituent member 13 having a laminated structure are used, but an integral structure may be used. In the optical module 100, the multilayer substrate 2 is used, but a single layer substrate may be used.

  In the optical module 100, the multilayer board 2 and the lower casing constituent member 12 are provided with the opening A, and the drive driver 5 is mounted on the heat sink 5a disposed in the opening A. However, the opening A is provided. Instead, the drive driver 5 may be mounted on the multilayer substrate 2. Moreover, in the optical module 100, although the supporting members 42a-42c were comprised by the separate member, you may comprise by a single member.

  Further, although the optical module 100 is an optical transmitter, the present invention is not limited to the optical transmitter and can be applied to an optical receiver. For example, when configuring an optical receiver, in the optical module 100, the assembly member 4 is replaced with, for example, a PD disposed on a base, and the drive driver 5 is replaced with a preamplifier. The optical signal input from the optical fiber stub 8 is received by the PD and converted into a high-frequency electrical signal, the converted electrical signal is amplified by a preamplifier, and the amplified electrical signal is transmitted from the lead terminal L1 to the outside. A wiring pattern or the like may be configured.

1 is a schematic plan view schematically showing an optical module according to an embodiment of the present invention. FIG. 2 is a schematic side sectional view schematically showing the optical module shown in FIG. 1. FIG. 2 is a schematic perspective sectional view schematically showing the optical module shown in FIG. 1. FIG. 2 is a schematic perspective view of a main part schematically showing the optical module shown in FIG. 1. It is explanatory drawing explaining the manufacturing method of the optical module shown in FIG. It is explanatory drawing explaining the manufacturing method of the optical module shown in FIG. It is the plane schematic diagram which represented typically the board | substrate of the uppermost layer among the board | substrates which comprise a multilayer substrate. It is the plane schematic diagram which represented typically the board | substrate of the 2nd layer from the top among the board | substrates which comprise a multilayer substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Multilayer substrate 2a, 2b, 42ba Wiring pattern 3 Space 4 Assembly member 5 Drive driver 5a Heat sink 6 Window pipe 7 Optical fiber connection pipe 8 Optical fiber stub 11 Base 12 Lower case component 13 Upper case configuration Member 14 Seal ring 15 Lid 21 and 22 Substrate 21a, 21b, 22a and 22b Notch 41 Electronic cooling element 42a to 42c Support member 43 Laser chip carrier 44 Semiconductor laser 45 Thermistor 46 Monitor PD
47 Lens holder 48 Lens 61 Window 100 Optical module A, A1, A2 Opening H1, H2 Via hole L1, L2 Lead terminals W1-W5 Wire

Claims (5)

A housing having a bottom base with high thermal conductivity;
An assembly member provided with a cooling element disposed in the casing on the base and an optical device that emits or receives at least laser light on the cooling element;
A heat sink disposed in the optical axis direction of the laser beam with respect to the assembly member in the casing on the base, and a high-frequency signal transmitted between the optical device and the outside of the casing on the heat sink Or an electronic device member provided with an electronic device for receiving;
Surrounding the assembly member and the electronic device member and extending in the optical axis direction of the laser light and extending outside the casing adjacent to the electronic device member, at least the optical device and the electronic device a substrate and a second wiring pattern is formed between the first wiring pattern and the electronic device and the outside of the casing between,
And connecting the optical device and the first wiring pattern, connecting the first wiring pattern and the electronic device, and connecting the electronic device and the second wiring pattern by wire bonding. And a lead terminal is provided on the wiring pattern outside the housing.   The optical module according to claim 1, wherein the substrate is formed by stacking a plurality of substrates.   The casing is formed by laminating a plurality of casing constituent members made of ceramic, and the substrate is made of ceramic and stacked between the plurality of casing constituent members. 3. The optical module according to claim 1, wherein a multilayer ceramic structure is formed integrally with the constituent members.   The optical module according to claim 1, wherein the optical device is a laser light emitting unit, and the electronic device is a driver that drives and controls the laser light emitting unit.   4. The optical device is a light receiving unit that receives laser light and converts it into an electrical signal, and the electronic device is an amplification unit that amplifies the converted electrical signal. The optical module as described in any one.

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