Light receiving module
By introducing a relay substrate into the optical receiving module, the problems of frequency band degradation caused by increased wire length and inability to miniaturize the module are solved, achieving both frequency band protection and module miniaturization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2020-07-06
- Publication Date
- 2026-06-16
Smart Images
Figure CN115943499B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to optical receiving modules. Background Technology
[0002] Waveguide-type light-receiving elements are end-face incident light-receiving elements that can balance high sensitivity and wide bandwidth. A method is proposed to mount such an end-face incident light-receiving element in a small / low-cost CAN packaged optical receiver module (e.g., see Patent Document 1).
[0003] Patent Document 1: Japanese Patent Application Publication No. 2004-88046
[0004] The existing module has the following problem: the length of the wire connecting the amplifier on the side of the block on the tube socket to the signal lead pin is increased, and the inductance of the wire increases, which degrades the frequency band.
[0005] In addition to the signal lead pins, multiple other lead pins also penetrate the socket. If the signal lead pins are brought closer to the block to shorten the wires, the freedom of arrangement for the multiple lead pins decreases. Therefore, it is not possible to arrange multiple lead pins in a way that reduces the radius of the circular socket, resulting in a larger module size. Summary of the Invention
[0006] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide an optical receiving module that prevents bandwidth degradation and can be miniaturized.
[0007] The optical receiving module disclosed herein is characterized by comprising: a circular socket; a plurality of lead pins passing through the socket and having signal lead pins; a block disposed on the upper surface of the socket; a waveguide-type light-receiving element disposed on the side of the block; an amplifier disposed on the side of the block and amplifying the electrical signal output from the waveguide-type light-receiving element; a first relay substrate disposed on the upper surface of the socket and positioned between the block and the signal lead pins; a first transmission line disposed on the first relay substrate; a first wire connecting one end of the first transmission line to the output terminal of the amplifier; and a second wire connecting the other end of the first transmission line to the signal lead pins.
[0008] In this disclosure, by providing a relay substrate on the upper surface of the socket, the flexibility in configuring multiple lead pins is increased, allowing multiple lead pins to be configured with a smaller radius of the circular socket. Furthermore, by using the relay substrate, the length of the wire between the amplifier and the signal lead pins is shortened, and the inductance of the wire is reduced. As a result, an optical receiver module that prevents bandwidth degradation and can be miniaturized can be obtained. Attached Figure Description
[0009] Figure 1 This is a perspective view showing the optical receiving module of Embodiment 1.
[0010] Figure 2 This is a circuit diagram of the optical receiving module in Implementation Method 1.
[0011] Figure 3 This is a cross-sectional view showing a waveguide-type light-receiving element.
[0012] Figure 4 This is a top view showing the optical receiving module of the comparative example.
[0013] Figure 5 This is a top view showing the optical receiving module of Embodiment 1.
[0014] Figure 6 This is an enlarged side view showing a modified example of the optical receiving module of Embodiment 1.
[0015] Figure 7 This is an enlarged side view showing a modified example of the optical receiving module of Embodiment 1.
[0016] Figure 8 This is a perspective view showing the optical receiving module of Embodiment 2.
[0017] Figure 9 This is a perspective view showing the optical receiving module of Embodiment 3. Detailed Implementation
[0018] The optical receiving module of the embodiment will be described with reference to the accompanying drawings. The same or corresponding components are labeled with the same reference numerals, and sometimes repeated descriptions are omitted.
[0019] Implementation method 1.
[0020] Figure 1 This is a perspective view showing the optical receiving module of Embodiment 1. Figure 2 This is a circuit diagram of the optical receiving module in Embodiment 1. The socket 1 is a circular conductor and is grounded.
[0021] Signal leads 2a and 2b and power leads 2c and 2d pass through the socket 1. Because an insulating sealing glass 3 is placed between the socket 1 and the leads 2a to 2d, they are mutually insulated. The tips of the leads 2a to 2d protrude from the upper surface of the socket 1.
[0022] A block 4 is disposed on the upper surface of the tube socket 1, and the upper surface of the tube socket 1 is joined to the lower surface of the block 4. In this embodiment, the block 4 is a conductor and is connected to the tube socket 1 to become ground potential. The sub-support 5, TIA (Transimpedance Amplifier) 6, and capacitors 7 and 8 are disposed on one side of the block 4. A waveguide-type light-receiving element 9 is mounted on the sub-support 5. The waveguide-type light-receiving element 9 is a PD (Photo Diode) or APD (Avalanche Photo Diode). Thus, since multiple structures are disposed on one side of the block 4, the lateral width of the block 4 is wider than the spacing between the lead pins 2c and 2d.
[0023] The lower surface electrodes of capacitors 7 and 8 are connected to block 4. The upper surface electrodes of capacitors 7 and 8 are connected to lead pins 2c and 2d via wires 10a and 10b, respectively. The upper surface electrode of capacitor 7 is connected to the cathode electrode of waveguide-type light-receiving element 9 via wire 10c. The upper surface electrode of capacitor 8 is connected to the power supply terminal of TIA6 via wire 10d. The anode electrode of waveguide-type light-receiving element 9 is connected to the input terminal of TIA6 via wire 10e.
[0024] A relay substrate 11, made of an insulator, is disposed on the upper surface of the tube base 1 and positioned between the block 4 and the lead pins 2a and 2b. Transmission lines 12a and 12b are provided on the relay substrate 11. One end of transmission line 12a is connected to the positive output terminal of the TIA6 via a wire 10f. One end of transmission line 12b is connected to the inverting output terminal of the TIA6 via a wire 10g. The other ends of transmission lines 12a and 12b are connected to the lead pins 2a and 2b via wires 10h and 10i, respectively. Wires 10a to 10i are, for example, Au wires.
[0025] A cap 14 with lens 13 is fixed to the upper surface of the tube base 1 to cover the waveguide-type light-receiving element 9, etc. The waveguide-type light-receiving element 9 is configured such that its end face is approximately perpendicular to the optical axis of the incident light from the optical fiber 15. The incident light from the optical fiber 15 is focused by the lens 13 and incident on the end face of the waveguide-type light-receiving element 9. Therefore, the waveguide-type light-receiving element 9 is disposed in the center of the circular tube base 1.
[0026] The waveguide-type light-receiving element 9 converts the incident light signal into an electrical signal. TIA6 is a differential amplifier that amplifies the electrical signal output from the waveguide-type light-receiving element 9. The differential output signal of TIA6 is output to the outside of the module via transmission lines 12a and 12b and lead pins 2a and 2b. Lead pin 2c is provided for supplying power to the waveguide-type light-receiving element 9. Lead pin 2d is provided for supplying power to TIA6.
[0027] Figure 3This is a cross-sectional view showing a waveguide-type light-receiving element. A semiconductor stack 17 is provided on a semiconductor substrate 16. The semiconductor stack 17 has a waveguide 18. An anode electrode 19 is provided on the semiconductor stack 17. A cathode electrode 20 is provided on the semiconductor substrate 16. The waveguide 18 serves as the light-receiving part of the waveguide-type light-receiving element 9.
[0028] Next, the effects of this embodiment will be compared with those of a comparative example for explanation. Figure 4 This is a top view of the optical receiver module of the comparative example. In this comparative example, the repeater substrate 11 is absent. Therefore, the non-inverting output terminal and the inverting output terminal of the TIA6 are directly connected to the lead pins 2a and 2b via wires 10h and 10i, respectively. If the signal lead pins 2a and 2b are brought closer to the block 4 to shorten the wires 10h and 10i, then multiple lead pins 2a to 2d are arranged in a row. Furthermore, the signal lead pins 2a and 2b need to be separated from the power supply lead pins 2c and 2d by a certain distance. This results in a larger radius for the circular socket 1.
[0029] Figure 5 This is a top view showing the optical receiving module of Embodiment 1. A relay substrate 11, connecting the TIA6 to the signal lead pins 2a and 2b, is disposed on the upper surface of the socket 1. The relay substrate 11 is positioned between the power supply lead pins 2c and 2d. By using the relay substrate 11, the freedom of arrangement of the multiple lead pins 2a to 2d is increased, allowing the multiple lead pins 2a to 2d to be arranged with a smaller radius of the circular socket 1. In addition, by using the relay substrate 11, the length of the wire between the TIA6 and the signal lead pins 2a and 2b is shortened, and the inductance of the wire is reduced. As a result, an optical receiving module that prevents bandwidth degradation and can be miniaturized can be obtained.
[0030] Figure 6 and Figure 7 This is an enlarged side view showing a modified example of the optical receiving module of Embodiment 1. Figure 6 In this configuration, lens 21 is bonded to the end face of waveguide-type light-receiving element 9 using adhesive 22. Figure 7 In this configuration, the lens 21 is bonded to the sub-support 5 at the front of the end face of the waveguide-type light-receiving element 9 using adhesive 22. This increases the optical coupling tolerance between the optical fiber 15 and the waveguide-type light-receiving element 9, thus mitigating the need for precise installation positioning.
[0031] Implementation method 2.
[0032] Figure 8This is a perspective view of the optical receiving module in Embodiment 2. A relay substrate 23 made of an insulator is disposed on the side of the block 4. Transmission lines 24a and 24b are provided on the relay substrate 23. One end of transmission line 24a is connected to the positive output of TIA6 via wire 10f. One end of transmission line 24b is connected to the inverted output of TIA6 via wire 10g. The other ends of transmission lines 24a and 24b are connected to transmission lines 12a and 12b via wires 10j and 10k, respectively. Alternatively, the two relay substrates 11 and 23 can be integrated into an L-shaped cross-section relay substrate.
[0033] In this embodiment, if the block 4 is made taller to adjust the height of the waveguide-type light-receiving element 9, then in embodiment 1, the wires 10f and 10g connecting the TIA6 on the side of the block 4 to the transmission lines 12a and 12b of the relay substrate 11 on the upper surface of the tube socket 1 are lengthened, increasing the inductance of the wires. In contrast, in this embodiment, by using the relay substrate 23 also on the side of the block 4, the wires 10f, 10g, 10j, and 10k can be shortened. This reduces the inductance and suppresses bandwidth degradation.
[0034] Furthermore, in Embodiment 1, when connecting the TIA6, which is on an orthogonal plane, to the relay substrate 11 with wires, space is required for capillary action, thus the wires become longer. In contrast, in this embodiment, when connecting the TIA6 and the relay substrate 23, which are on the same plane, there is sufficient space for capillary action, thus the wires can be shortened. Other structures and effects are the same as in Embodiment 1.
[0035] Alternatively, transmission lines 24a and 24b can be connected to transmission lines 12a and 12b using solder. This shortens the overall conductor length, thereby further reducing inductance.
[0036] Implementation method 3.
[0037] Figure 9 This is a perspective view of the optical receiving module in Embodiment 3. In this embodiment, the block 4 is made of an insulating material such as ceramic. A GND wiring pattern 25 and transmission lines 24a and 24b are provided on the surface of the block 4. One end of the transmission lines 24a and 24b are connected to the positive and negative outputs of the TIA6, respectively, via wires 10f and 10g. The other ends of the transmission lines 24a and 24b are bonded to the transmission lines 12a and 12b, respectively, via solder 26a and 26b. Alternatively, the transmission lines 24a and 24b can be connected to the transmission lines 12a and 12b via wires. In this embodiment, by providing the transmission lines 24a and 24b on the surface of the insulating block 4, the relay substrate 23 on the block 4 can be omitted. Other structures and effects are the same as in Embodiment 2.
[0038] Explanation of reference numerals in the attached figures
[0039] 1…Socket; 2a, 2b…Lead pins (signal lead pins); 2c…Lead pins (first power supply lead pins); 2d…Lead pins (second power supply lead pins); 4…Block; 5…Sub-support; 9…Waveguide-type light receiving element; 10f, 10g…Wires (first wires); 10h, 10i…Wires (second wires); 11…Relay substrate (first relay substrate); 12a, 12b…Transmission line (first transmission line); 21…Lens; 23…Relay substrate (second relay substrate); 24a, 24b…Transmission line (second transmission line); 26a, 26b…Solder.
Claims
1. An optical receiving module, characterized by comprising: have: Circular tube base; Multiple lead pins that pass through the socket and have signal lead pins; A block, which is disposed on the upper surface of the tube seat; A waveguide-type light-receiving element is disposed on the side of the block; An amplifier is disposed on the side of the block and amplifies the electrical signal output from the waveguide-type light-receiving element; A first capacitor is disposed on the side of the block and connected to the waveguide-type light-receiving element; A second capacitor is disposed on the side of the block and connected to the amplifier; A first relay substrate is disposed on the upper surface of the tube socket and positioned between the block and the signal lead pin; A first transmission line is disposed on the first relay substrate; A first wire connects one end of the first transmission line to the output terminal of the amplifier; as well as The second conductor connects the other end of the first transmission line to the signal via a lead pin. The plurality of lead pins include: a first power supply lead pin for supplying power to the waveguide-type light-receiving element, and a second power supply lead pin for supplying power to the amplifier. The first relay substrate is disposed between the first power supply lead pin and the second power supply lead pin. The first power supply lead pin is connected to the first capacitor wire without passing through the first relay substrate. The second power supply lead pin is connected to the second capacitor wire without passing through the first relay substrate.
2. The optical receiving module according to claim 1, characterized by It also has: A second relay substrate is disposed on the side of the block; and The second transmission line is disposed on the second relay substrate. One end of the second transmission line is connected to the output terminal of the amplifier, and the other end is connected to one end of the first transmission line.
3. The optical receiving module according to claim 2, characterized in that, The first relay substrate and the second relay substrate are integrated.
4. The optical receiving module according to claim 1, characterized in that, It also includes a second transmission line disposed on the side of the block. The block is made of insulating material. One end of the second transmission line is connected to the output terminal of the amplifier, and the other end of the second transmission line is connected to one end of the first transmission line.
5. The optical receiving module according to any one of claims 2 to 4, characterized in that, The other end of the second transmission line is connected to one end of the first transmission line by solder.
6. The optical receiving module according to any one of claims 1 to 5, characterized in that, It also includes a lens that is bonded to the end face of the waveguide-type light-receiving element.
7. The optical receiving module according to any one of claims 1 to 5, characterized by It also has: A secondary support, disposed on the side of the block, and on which the waveguide-type light-receiving element is mounted; and A lens is attached to the sub-support at the front of the end face of the waveguide-type light-receiving element.