Optical transceiver module and inspection system

Abstract

An optical transmitter receiver module (1) comprises a light chip (5) including an optical transmitting device (50) and an optical receiving device (51), a transmission analog IC (3), a reception analog IC (4), a signal processing LSI (2), a level converting circuit (6) that converts an intensity monitor signal outputted from a driver circuit (30) to a level matching the gain control signal of a trans-impedance amplifier (40), a switch (7) provided between the intensity monitor terminal of the driver circuit (30) and the input terminal of the level conversion circuit (6), and a switch (8) provided between the output terminal of the level converting circuit (6) and the gain control terminal of the trans-impedance amplifier (40).

Description

[Technical Field]

[0001] The present invention relates to an optical transceiver module in which multiple devices such as an optical chip, an analog IC, and a signal processing LSI are integrated into a single package, and to an inspection system for the optical transceiver module. [Background technology]

[0002] In the field of optical communications, the integration of multiple devices such as optical chips, analog ICs (Integrated Circuits), and signal processing LSIs (Large Scale Integration) into a single package is progressing in order to increase communication capacity and reduce power consumption. As more devices are integrated into a single package, the system becomes more complex, and the number of inspection items required for shipping inspections and other purposes increases, and the required inspection time also tends to increase. Since increased inspection time leads to increased product costs, it is necessary to shorten the inspection time.

[0003] As disclosed in Patent Document 1, it has been possible to check whether wiring is properly connected to a device inside an optical module by directly contacting the terminal of the optical module using a spring connector or the like. Fig. 14 is a flowchart illustrating a conventional optical module inspection process. In the inspection of the optical module after package assembly, as disclosed in Patent Document 1, the terminals of the optical module are connected to an inspection device via a spring connector or the like, and a continuity test is performed on each terminal of the optical module (Fig. 14, step S100).

[0004] If the continuity test results in no problems (YES in step S101 in FIG. 14), a system test is performed to check whether there are any abnormalities in the operation of the optical module (step S102 in FIG. 14). On the other hand, for optical modules that have a continuity defect, the system test is not performed to shorten the test time.

[0005] In an optical module in which multiple devices such as an optical chip, an analog IC, and a signal processing LSI are integrated into one package, for example, as shown in Fig. 15, some of the terminals 102 of a signal processing LSI 101 and terminals 104 of an analog IC 103 mounted on a PCB (Printed Circuit Board) 100 are connected to terminals 105 for connection to the outside of the package. Therefore, it is possible to perform a continuity test on terminals 102 and 104 connected to terminal 105.

[0006] On the other hand, it was difficult to find defects in the signal wiring 106 between the signal processing LSI 101 and the analog IC 103 by a continuity test because the signal wiring 106 was not connected to the terminal 105. Therefore, even if there was an abnormality in the connection of the signal wiring 106, the abnormality could not be found until the end of the test process, which could result in wasted time. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-194041 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned problems, and has an object to provide an optical transceiver module and an inspection system that can improve the efficiency of inspection. [Means for solving the problem]

[0009] The optical transmitting and receiving module of the present invention is characterized by comprising: an optical chip having an optical transmitting device and an optical receiving device; a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmitting signal; a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier; a signal processing LSI configured to output the transmitting signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a receiving signal; a level conversion circuit configured to convert an intensity monitor signal output from the driver circuit to a level suitable for a gain control signal of the transimpedance amplifier; a first switch provided between the intensity monitor terminal of the driver circuit and the input terminal of the level conversion circuit; and a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier. [Effects of the Invention]

[0010] According to the present invention, an optical transceiver module is provided with a level conversion circuit that converts the intensity monitor signal output from the driver circuit to a level compatible with the gain control signal of the transimpedance amplifier, a first switch that connects the intensity monitor terminal of the driver circuit to the input terminal of the level conversion circuit, and a second switch that connects the output terminal of the level conversion circuit to the gain control terminal of the transimpedance amplifier, thereby making it possible to easily check the normality of the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI without performing a system test, thereby realizing efficient testing of the optical transceiver module and, as a result, reducing product costs. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing the configuration of an optical transceiver module according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a block diagram showing the configuration of an inspection system according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart illustrating the operation of the inspection device according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing a test signal output from the signal processing LSI in the first embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an intensity monitor signal output from a driver circuit of a transmitting analog IC in the first embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing an analog signal output from a transimpedance amplifier of a receiving analog IC in the first embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing the configuration of an inspection system according to a second embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart illustrating the operation of the inspection device according to the second embodiment of the present invention. [Figure 9] FIG. 9 is a block diagram showing the configuration of an inspection system according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a block diagram showing the configuration of an inspection system according to a fourth embodiment of the present invention. [Figure 11] FIG. 11 is a block diagram showing the configuration of an inspection system according to the fifth embodiment of the present invention. [Figure 12] FIG. 12 is a block diagram showing the configuration of an inspection system according to a sixth embodiment of the present invention. [Figure 13] FIG. 13 is a block diagram showing an example of the configuration of a computer that realizes the inspection apparatus according to the first to sixth embodiments of the present invention. [Figure 14] FIG. 14 is a flowchart illustrating a conventional optical module inspection process. [Figure 15] FIG. 15 is a cross-sectional view of a conventional optical module. DETAILED DESCRIPTION OF THE INVENTION

[0012] [First Example] Embodiments of the present invention will now be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of an optical transceiver module according to a first embodiment of the present invention. Optical transceiver module 1 integrates a signal processing LSI 2, a transmitting analog IC 3, a receiving analog IC 4, an optical chip 5, a level conversion circuit 6, and switches 7 and 8.

[0013] The signal processing LSI 2 performs digital signal processing such as error correction coding, waveform shaping, and pre-equalization on the transmission signal, and converts the processed digital signal into an analog signal using a DAC (Digital to Analog Converter) 20. The signal processing LSI 2 also converts the analog signal output from the receiving analog IC 4 into a digital signal using an ADC (Analog-to-Digital Converter) 21, and performs digital signal processing such as waveform distortion compensation and error correction decoding on the digital signal to obtain a received signal.

[0014] The transmitting analog IC 3 includes a driver circuit (DRV) 30. The DRV 30 drives an optical transmitting device 50, such as an LD (Laser Diode) or an optical modulator, in the optical chip 5 in response to the analog signal output from the DAC 20. The DRV 30 amplifies the intensity of the analog signal to a level that can drive the optical transmitting device 50. The DRV 30 also includes an intensity detection function that detects the intensity of the analog output signal of the DRV 30, and outputs an intensity monitor signal indicating the detection result to an intensity monitor terminal PKD.

[0015] The receiving analog IC 4 includes a transimpedance amplifier (TIA) 40. The TIA 40 converts a current signal obtained by an optical receiving device 51 such as a PD (Photo Diode) in the optical chip 5 into a voltage signal and amplifies it. The TIA 40 is also a variable gain amplifier, and its gain can be adjusted by a gain control signal input to a gain control terminal GC1.

[0016] The switch 7 selectively connects the intensity monitor terminal PKD of the DRV30 to either the input terminal of the level conversion circuit 6 or the intensity monitor terminal PKDO of the optical transceiver module 1. The switch 8 selectively connects the gain control terminal GC1 of the TIA 40 to either the output terminal of the level conversion circuit 6 or the gain control terminal GCI1 of the optical transceiver module 1. The switches 7 and 8 can be controlled by a mode control signal input to the mode control terminal MCTL of the optical transceiver module 1.

[0017] The level conversion circuit 6 converts the intensity monitor signal output from the DRV 30 and input via the switch 7 into a level that matches the gain control signal of the TIA 40 .

[0018] 2 is a block diagram showing the configuration of an inspection system including the optical transceiver module 1 and an inspection device 9. The inspection device 9 includes a control unit 90 and an inspection unit 91.

[0019] 3 is a flowchart illustrating the operation of the inspection device 9. After connecting the optical transceiver module 1 to the inspection device 9, the inspection unit 91 of the inspection device 9 performs a continuity test on each terminal of the optical transceiver module 1 in the same manner as in the conventional method (step S10 in FIG. 3).

[0020] If there is no problem in the continuity test (YES in step S11 in FIG. 3), a simple test is performed to check the normality of the connection between the signal processing LSI 2 and the transmitting analog IC 3, and the normality of the connection between the receiving analog IC 4 and the signal processing LSI 2. In this simple test, the test environment is set up so that light of a certain intensity is incident on the optical receiving device 51 in the optical chip 5.

[0021] The control unit 90 of the inspection device 9 outputs a mode control signal. In response to the mode control signal input via the mode control terminal MCTL, the switch 7 selects the input terminal of the level conversion circuit 6, and the switch 8 selects the output terminal of the level conversion circuit 6. In this way, the intensity monitor terminal PKD of the DRV30 and the input terminal of the level conversion circuit 6 are connected via the switch 7, and the output terminal of the level conversion circuit 6 and the gain control terminal GC1 of the TIA 40 are connected via the switch 8 (step S12 in FIG. 3).

[0022] When no mode control signal is input from the mode control terminal MCTL, the switch 7 connects the intensity monitor terminal PKD of the DRV 30 to the intensity monitor terminal PKDO of the optical transceiver module 1. The switch 8 connects the gain control terminal GC1 of the TIA 40 to the gain control terminal GCI1 of the optical transceiver module 1.

[0023] Next, the inspection signal output unit 22 of the signal processing LSI 2 outputs the inspection signal in response to an instruction from, for example, the control unit 90 of the inspection device 9 (step S13 in FIG. 3). The inspection signal is a signal whose signal intensity is periodically changed by intensity-modulating (AM) a main signal having the same frequency as the transmission signal for optical communication at a frequency lower than that of the main signal. The inspection signal undergoes digital signal processing by the signal processing LSI 2 in the same way as the transmission signal for optical communication, and the processed digital signal is converted into an analog signal by the DAC 20. In this way, an inspection signal S1 having a waveform such as that shown in FIG. 4 is output from the DAC 20 to the transmitting analog IC 3.

[0024] The DRV30 of the transmitting analog IC3 amplifies the inspection signal S1 output from the DAC20 and outputs it to the optical chip 5. At this time, the DRV30 outputs an intensity monitor signal S2 indicating the intensity of the analog output signal to be output to the optical chip 5 to the intensity monitor terminal PKD. In this way, the intensity monitor signal S2 having a waveform such as that shown in FIG. 5 is output from the DRV30.

[0025] The level conversion circuit 6 converts the intensity monitor signal S2 output from the DRV 30 and input via the switch 7 to a level that matches the gain control signal of the TIA 40 and outputs the converted signal to the switch 8.

[0026] The TIA 40 in the receiving analog IC 4 receives the signal input to the gain control terminal GC1 via the switch 8 as a gain control signal, and amplifies the signal output from the optical receiving device 51 in the optical chip 5 with a gain corresponding to the gain control signal. If the test environment is set so that a constant intensity of light is incident on the optical receiving device 51, the intensity of the signal output from the optical receiving device 51 will be constant. On the other hand, the gain control signal is a level-converted version of the intensity monitor signal S2, and therefore the signal intensity changes periodically. Therefore, the gain of the TIA 40 changes periodically, and the analog signal S3 output from the TIA 40 becomes a signal whose intensity changes periodically, as shown in FIG. 6, for example.

[0027] The ADC 21 of the signal processing LSI 2 converts the analog signal S3 output from the TIA 40 into a digital signal. The intensity monitor 23 of the signal processing LSI 2 detects the intensity of the signal received from the TIA 40 via the ADC 21 (step S14 in FIG. 3). S4 in FIG.

[0028] If the connection between the signal processing LSI 2 and the transmitting analog IC 3 and the connection between the receiving analog IC 4 and the signal processing LSI 2 are both normal, the signal strength detected by the strength monitor unit 23 will change periodically. If the detected signal strength has the same frequency components as the strength change of the inspection signal, the strength monitor unit 23 determines that the connection between the signal processing LSI 2 and the transmitting analog IC 3 and the connection between the receiving analog IC 4 and the signal processing LSI 2 are normal (YES in step S15 of Figure 3).

[0029] Furthermore, if the intensity monitor unit 23 cannot detect a signal from the TIA 40, if the detected signal intensity is weak and below a threshold, or if the detected signal intensity does not contain the same frequency components as the intensity change of the inspection signal, it determines that at least one of the connection between the signal processing LSI 2 and the transmitting analog IC 3 and the connection between the receiving analog IC 4 and the signal processing LSI 2 is faulty (NO in step S15).

[0030] The inspection unit 91 of the inspection device 9 receives the inspection results from the intensity monitor unit 23 from the monitor terminal MOUT of the optical transceiver module 1, and if there are no problems with the connection, performs a system inspection to check whether there are any abnormalities in the operation of the optical transceiver module 1, as in the conventional case (step S16 in Figure 3).

[0031] During system testing, the control unit 90 of the testing device 9 returns the switches 7 and 8 of the optical transceiver module 1 to their normal states. That is, the switch 7 connects the intensity monitor terminal PKD of the DRV 30 to the intensity monitor terminal PKDO of the optical transceiver module 1. The switch 8 connects the gain control terminal GC1 of the TIA 40 to the gain control terminal GCI1 of the optical transceiver module 1.

[0032] An example of a system test is to input a test transmission signal to the signal processing LSI 2 to check the optical output of the optical transmitting device 50 in the optical chip 5, or to input an optical signal to the optical receiving device 51 in the optical chip 5 to check the received signal output of the signal processing LSI 2. Needless to say, there are various system test items other than these examples. If the result of the system test is normal, the test of the optical transceiver module 1 is completed.

[0033] As described above, in this embodiment, it is possible to easily check the normality of the connection between the signal processing LSI 2 and the transmitting analog IC 3, and the normality of the connection between the receiving analog IC 4 and the signal processing LSI 2 without performing a system inspection, thereby making it possible to efficiently inspect the optical transmitting and receiving module 1.

[0034] [Second Example] Next, a second embodiment of the present invention will be described. Fig. 7 is a block diagram showing the configuration of an inspection system comprising an optical transceiver module 1 and an inspection device 9a. The inspection device 9a comprises a control unit 90, an inspection unit 91, and a gain control unit 92.

[0035] 8 is a flowchart illustrating the operation of the inspection device 9a. The processing of steps S10 to S13 is the same as that described in the first embodiment. During a simple test to check the normality of the connection between the signal processing LSI 2 and the transmitting analog IC 3 and the normality of the connection between the receiving analog IC 4 and the signal processing LSI 2, the gain control unit 92 of the test device 9a outputs a gain control signal for controlling the gain of the DRV 30 (step S17 in FIG. 8). At this time, the gain control unit 92 outputs a gain control signal whose intensity changes at a frequency different from the frequency of the intensity change of the test signal output by the test signal output unit 22.

[0036] The gain control signal output from the gain control section 92 is input to the gain control terminal GC2 of the DRV30 via the gain control terminal GCI2 of the optical transmitting and receiving module 1. The DRV 30 amplifies the inspection signal output from the DAC 20 with a gain according to the gain control signal input to the gain control terminal GC 2 , and outputs the amplified signal to the optical chip 5 .

[0037] The operations of the level conversion circuit 6, the TIA 40, and the ADC 21 are as described in the first embodiment. As in the first embodiment, the intensity monitor unit 23 of the signal processing LSI 2 detects the intensity of the signal received from the TIA 40 via the ADC 21 (step S14 in FIG. 8).

[0038] In this embodiment, the strength of the inspection signal is changed periodically as in the first embodiment, and further, the strength of the gain control signal input from the gain control unit 92 to the DRV 30 is changed at a frequency different from the frequency at which the strength of the inspection signal changes. Therefore, if the connection between the signal processing LSI 2 and the transmitting analog IC 3, the connection between the receiving analog IC 4 and the signal processing LSI 2, and the connection at the gain control terminal GC2 of the DRV 30 are all normal, the signal strength detected by the strength monitor unit 23 will have two frequency components.

[0039] If the detected signal strength has the same frequency components as the strength change of the inspection signal and the same known frequency components as the strength change of the gain control signal input to the DRV30, the strength monitor unit 23 determines that the connection between the signal processing LSI2 and the transmitting analog IC3 and the connection between the receiving analog IC4 and the signal processing LSI2 are normal, and that the connection of the gain control terminal GC2 of the DRV30 is also normal (YES in step S15a of FIG. 8).

[0040] Furthermore, if the intensity monitor unit 23 cannot detect a signal from the TIA 40, if the detected signal intensity is weak and below a threshold, if the detected signal intensity does not contain the same frequency component as the intensity change of the inspection signal, or if the detected signal intensity does not contain the same frequency component as the intensity change of the gain control signal input to the DRV30, it determines that at least one of the connection between the signal processing LSI2 and the transmitting analog IC3, the connection between the receiving analog IC4 and the signal processing LSI2, and the connection of the gain control terminal GC2 of the DRV30 is faulty (NO in step S15a).

[0041] The inspection unit 91 of the inspection device 9 receives the inspection result from the intensity monitor unit 23 from the monitor terminal MOUT of the optical transceiver module 1, and if there is no problem with the connection, performs a system inspection (step S16 in FIG. 8).

[0042] In this embodiment, it is possible to check not only the normality of the connection between the signal processing LSI2 and the transmitting analog IC3, and the normality of the connection between the receiving analog IC4 and the signal processing LSI2, but also the normality of the connection of the gain control terminal GC2 of the DRV30.

[0043] [Third Example] Next, a third embodiment of the present invention will be described. Fig. 9 is a block diagram showing the configuration of an inspection system comprising an optical transceiver module 1a and an inspection device 9b. The optical transceiver module 1a is the optical transceiver module 1 of the first and second embodiments, except that the level conversion circuit 6 and switches 7 and 8 are removed, and the gain control terminal GC1 of the TIA 40 is connected to the gain control terminal GCI1, and the intensity monitor terminal PKD of the DRV30 is connected to the intensity monitor terminal PKDO.

[0044] The inspection device 9b includes a control unit 90, an inspection unit 91, a level conversion circuit 93, and switches 94 and 95.

[0045] The switch 94 selectively connects the intensity monitor terminal PKDO of the optical transmitting and receiving module 1a to either the input terminal of the level conversion circuit 93 or another circuit (e.g., the inspection unit 91) in the inspection device 9b. The switch 95 selectively connects the gain control terminal GCI1 of the optical transmitting and receiving module 1a to either the output terminal of the level conversion circuit 93 or another circuit (e.g., the gain control unit) in the inspection device 9b.

[0046] The flow of testing the optical transceiver module 1a is the same as in the first embodiment, so the operation of the testing device 9b will be explained using Fig. 3. The process of step S10 is the same as that explained in the first embodiment.

[0047] If the continuity test results in no problems (YES in step S11 in FIG. 3), the control unit 90 of the inspection device 9b causes the switch 94 to select the input terminal of the level conversion circuit 93 and the switch 95 to select the output terminal of the level conversion circuit 93. In this way, the intensity monitor terminal PKD of the DRV30 and the input terminal of the level conversion circuit 93 are connected via the switch 94, and the output terminal of the level conversion circuit 93 and the gain control terminal GC1 of the TIA 40 are connected via the switch 95 (step S12 in FIG. 3).

[0048] As in the first embodiment, the test signal output unit 22 of the signal processing LSI 2 outputs a test signal (step S13 in FIG. 3). A level conversion circuit 93 of the inspection device 9b converts the intensity monitor signal output from the DRV 30 and input via the intensity monitor terminal PKDO and a switch 94 to a level suitable for the gain control signal of the TIA 40 and outputs it to a switch 95.

[0049] The TIA 40 of the receiving analog IC 4 receives the signal input to the gain control terminal GC1 via the switch 95 and the gain control terminal GCI1 as a gain control signal, and amplifies the signal output from the optical receiving device 51 in the optical chip 5 with a gain according to the gain control signal. The processing in steps S14 and S15 is the same as that described in the first embodiment.

[0050] The inspection unit 91 of the inspection device 9b receives the inspection result from the intensity monitor 23 from the monitor terminal MOUT of the optical transceiver module 1a, and if there is no problem with the connection, performs a system inspection of the optical transceiver module 1a (step S16 in FIG. 3).

[0051] During the system inspection, the control unit 90 of the inspection device 9b causes the switch 94 to select a connection to a circuit (e.g., the inspection unit 91) other than the level conversion circuit 93, and causes the switch 95 to select a connection to a circuit (e.g., a gain control unit) other than the level conversion circuit 93. If the result of the system inspection is normal, the inspection of the optical transceiver module 1a is completed.

[0052] As described above, in this embodiment, since there is no need to mount a level conversion circuit in the optical transmitting and receiving module 1a, it is possible to reduce the area of ​​the optical transmitting and receiving module 1a.

[0053] [Fourth Example] Next, a fourth embodiment of the present invention will be described. Fig. 10 is a block diagram showing the configuration of an inspection system comprising an optical transceiver module 1a and an inspection device 9c. The inspection device 9c of this embodiment is obtained by adding a gain control unit 92 to the inspection device 9b of the third embodiment.

[0054] The flow of testing the optical transceiver module 1a is the same as in the second embodiment, so the operation of the testing device 9c will be explained using Fig. 8. The process of step S10 is the same as that explained in the first embodiment.

[0055] As in the third embodiment, if the continuity test results in no problems (YES in step S11 of FIG. 8), the control unit 90 of the inspection device 9c causes the switch 94 to select the input terminal of the level conversion circuit 93 and the switch 95 to select the output terminal of the level conversion circuit 93 (step S12 of FIG. 8).

[0056] As in the first embodiment, the check signal output unit 22 of the signal processing LSI 2 outputs a check signal (step S13 in FIG. 8). As in the second embodiment, the gain control unit 92 of the inspection device 9c outputs a gain control signal (step S17 in FIG. 8).

[0057] The DRV 30 amplifies the inspection signal output from the DAC 20 with a gain according to the gain control signal input to the gain control terminal GC 2 , and outputs the amplified signal to the optical chip 5 . The operations of the level conversion circuit 93 and the TIA 40 are as described in the third embodiment. The processes of steps S14 and S15a are as described in the second embodiment.

[0058] The inspection unit 91 of the inspection device 9c receives the inspection result from the intensity monitor 23 from the monitor terminal MOUT of the optical transceiver module 1a, and if there is no problem with the connection, performs a system inspection of the optical transceiver module 1a (step S16 in FIG. 8).

[0059] In this embodiment, it is possible to reduce the area of ​​the optical transceiver module 1a, as in the third embodiment. Furthermore, in this embodiment, it is possible to check not only the normality of the connection between the signal processing LSI2 and the transmitting analog IC3, and the normality of the connection between the receiving analog IC4 and the signal processing LSI2, but also the normality of the connection of the gain control terminal GC2 of the DRV30, as in the second embodiment.

[0060] [Fifth Example] Next, a fifth embodiment of the present invention will be described below. Fig. 11 is a block diagram showing the configuration of an inspection system comprising an optical transceiver module 1b and an inspection device 9d. In the optical transceiver module 1b of this embodiment, a signal processing LSI 2b, a transmitting analog IC 3, a receiving analog IC 4, an optical chip 5, a level conversion circuit 6, and switches 7 and 8 are integrated.

[0061] The inspection device 9d includes a control unit 90, an inspection unit 91, an inspection signal output unit 96, and an intensity monitor unit 97. In the first to fourth embodiments, the inspection signal output unit 22 and the intensity monitor unit 23 are provided in the signal processing LSI 2 of the optical transceiver module 1, 1a. In contrast, in this embodiment, the inspection signal output unit 96 and the intensity monitor unit 97 are provided in the inspection device 9d.

[0062] The flow of testing the optical transceiver module 1b is the same as in the first embodiment, so the operation of the testing device 9d will be explained using Fig. 3. The processing of steps S10 to S12 is the same as that explained in the first embodiment.

[0063] The inspection signal output unit 96 of the inspection device 9d outputs an inspection signal in response to, for example, an instruction from the control unit 90 (step S13 in FIG. 3). The inspection signal is input from the input terminal IN of the optical transceiver module 1b to the signal processing LSI 2b, and undergoes digital signal processing by the signal processing LSI 2b in the same way as a transmission signal for optical communication. The processed digital signal is converted into an analog signal by the DAC 20. The operations of the DRV 30, the level conversion circuit 6, the switches 7 and 8, the TIA 40, and the ADC 21 are as described in the first embodiment.

[0064] The intensity monitor 97 of the inspection device 9d receives the signal received by the signal processing LSI 2b from the TIA 40 via the ADC 21 through the monitor terminal MOUT of the optical transmitting and receiving module 1b, and detects the intensity of the received signal (step S14 in FIG. 3).

[0065] If the detected signal strength has the same frequency components as the strength change of the inspection signal, the strength monitor unit 97 determines that the connection between the signal processing LSI 2b and the transmitting analog IC 3 and the connection between the receiving analog IC 4 and the signal processing LSI 2b are normal (YES in step S15 of Figure 3).

[0066] Furthermore, if the intensity monitor unit 97 cannot detect a signal, if the detected signal intensity is weak and below a threshold, or if the detected signal intensity does not contain the same frequency components as the intensity change of the inspection signal, it determines that at least one of the connection between the signal processing LSI 2b and the transmitting analog IC 3 and the connection between the receiving analog IC 4 and the signal processing LSI 2b is faulty (NO in step S15).

[0067] The inspection unit 91 of the inspection device 9d receives the inspection result from the intensity monitor unit 97, and if there is no problem with the connection, performs a system inspection of the optical transmitting and receiving module 1b (step S16 in FIG. 3).

[0068] As described above, in this embodiment, since there is no need to mount a test signal output unit and an intensity monitor unit in the signal processing LSI 2b of the optical transceiver module 1b, it is possible to reduce the area of ​​the optical transceiver module 1b.

[0069] The inspection device may be provided with only one of the inspection signal output unit 96 and the intensity monitor unit 97. As in the second embodiment, the gain control unit 92 may be added to the inspection device.

[0070] [Sixth Example] Next, a sixth embodiment of the present invention will be described below. Fig. 12 is a block diagram showing the configuration of an inspection system comprising an optical transceiver module 1c and an inspection device 9e. The optical transceiver module 1c is the optical transceiver module 1b of the fifth embodiment, except that the level conversion circuit 6 and switches 7 and 8 have been removed, and the gain control terminal GC1 of the TIA 40 is connected to the gain control terminal GCI1, and the intensity monitor terminal PKD of the DRV30 is connected to the intensity monitor terminal PKDO.

[0071] The test device 9e is obtained by adding a gain control section 92, a level conversion circuit 93, and switches 94 and 95 to the test device 9d of the fifth embodiment. The operation of the inspection device 9e is the same as in the first to fifth embodiments, and therefore a detailed description thereof will be omitted.

[0072] As in the third embodiment, the inspection device may be configured such that only the level conversion circuit 93 and the switches 94 and 95 are added, and the gain control section 92 is not included.

[0073] At least a part of the inspection devices 9, 9a to 9e described in the first to sixth embodiments can be realized by a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. An example of the configuration of this computer is shown in Figure 13.

[0074] The computer includes a CPU 200, a storage device 201, and an interface device (I / F) 202. Hardware such as switches 94 and 95, an inspection signal output unit 96, and an intensity monitor unit 97 are connected to the I / F 202. In such a computer, a program for realizing the inspection method of the present invention is stored in the storage device 201. The CPU 200 executes the processes described in the first to sixth embodiments in accordance with the program stored in the storage device 201.

[0075] Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes.

[0076] (Supplementary Note 1) The optical transmitting and receiving module of the present invention comprises an optical chip having an optical transmitting device and an optical receiving device, a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmitting signal, a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier, a signal processing LSI configured to output the transmitting signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a receiving signal, a level conversion circuit configured to convert an intensity monitor signal output from the driver circuit to a level compatible with a gain control signal of the transimpedance amplifier, a first switch provided between the intensity monitor terminal of the driver circuit and the input terminal of the level conversion circuit, and a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier.

[0077] (Supplementary Note 2) In the optical transmitting and receiving module described in Supplementary Note 1, the signal processing LSI comprises: an inspection signal output unit configured to output, to the transmitting analog IC, an inspection signal whose signal strength is periodically changed at a frequency lower than that of the transmitting signal, during an inspection to check the normality of the connection between the signal processing LSI and the transmitting analog IC and the normality of the connection between the receiving analog IC and the signal processing LSI; and an intensity monitor unit configured to detect the intensity of the signal received from the receiving analog IC during the inspection.

[0078] (Supplementary Note 3) An inspection system of the present invention comprises the optical transmitting and receiving module described in Supplementary Note 2 and an inspection device for the optical transmitting and receiving module, wherein the inspection device comprises a first control unit configured to control the first and second switches so that, during the inspection, an intensity monitor terminal of the driver circuit is connected to an input terminal of the level conversion circuit and an output terminal of the level conversion circuit is connected to a gain control terminal of the transimpedance amplifier, and the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the inspection signal.

[0079] (Supplementary Note 4) In the test system described in Supplementary Note 3, the test device further includes a second control unit configured to output, during the test, to a gain control terminal of the driver circuit a gain control signal whose intensity changes at a frequency different from the frequency of the intensity change of the test signal, and the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal, and that the connection of the gain control terminal of the driver circuit is also normal, when the detected signal intensity has the same frequency component as the intensity change of the test signal and the same frequency component as the intensity change of the gain control signal.

[0080] (Supplementary Note 5) The inspection system of the present invention comprises an optical transmitting and receiving module and an inspection device for the optical transmitting and receiving module, the optical transmitting and receiving module comprising an optical chip having an optical transmitting device and an optical receiving device, a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmission signal, a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier, and a signal processing LSI configured to output the transmission signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a reception signal, the signal processing LSI comprising an inspection signal output unit configured to output to the transmitting analog IC an inspection signal whose signal strength is periodically changed at a frequency lower than that of the transmission signal during an inspection to check the normality of the connection between the signal processing LSI and the transmitting analog IC and the normality of the connection between the receiving analog IC and the signal processing LSI, and and an intensity monitor unit configured to detect the intensity of the intensity monitor signal output from the driver circuit, wherein the testing device comprises: a level conversion circuit configured to convert the intensity monitor signal output from the driver circuit to a level compatible with the gain control signal of the transimpedance amplifier; a first switch provided between the intensity monitor terminal of the driver circuit and the input terminal of the level conversion circuit; a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier; and a first control unit configured to control the first and second switches so that, during the testing, the intensity monitor terminal of the driver circuit is connected to the input terminal of the level conversion circuit and the output terminal of the level conversion circuit is connected to the gain control terminal of the transimpedance amplifier, and the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the testing signal.

[0081] (Supplementary Note 6) A testing system of the present invention comprises the optical transmitting and receiving module according to Supplementary Note 1 and a testing device for the optical transmitting and receiving module, wherein the testing device comprises: a test signal output unit configured to output to the transmitting analog IC a test signal whose signal strength is periodically changed at a frequency lower than that of the transmission signal during a test to check the normality of the connection between the signal processing LSI and the transmitting analog IC and the normality of the connection between the receiving analog IC and the signal processing LSI; an intensity monitor unit configured to detect the strength of the signal received from the receiving analog IC during the test; and a first control unit configured to control the first and second switches so that during the test, the intensity monitor terminal of the driver circuit is connected to the input terminal of the level conversion circuit and the output terminal of the level conversion circuit is connected to the gain control terminal of the transimpedance amplifier, and the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal strength has the same frequency component as the intensity change of the test signal.

[0082] (Supplementary Note 7) An inspection system of the present invention comprises an optical transmitting and receiving module and an inspection apparatus for the optical transmitting and receiving module, the optical transmitting and receiving module comprising an optical chip having an optical transmitting device and an optical receiving device, a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmission signal, a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier, and a signal processing LSI configured to output the transmission signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a reception signal, the inspection apparatus comprising a level conversion circuit configured to convert an intensity monitor signal output from the driver circuit to a level suitable for a gain control signal of the transimpedance amplifier, a first switch provided between an intensity monitor terminal of the driver circuit and an input terminal of the level conversion circuit, and a second switch provided between an output terminal of the level conversion circuit and a gain control signal of the transimpedance amplifier. a second switch provided between the signal processing LSI and the transmitting analog IC and the signal processing LSI; a test signal output unit configured to output to the transmitting analog IC a test signal whose signal strength is periodically changed at a frequency lower than that of the transmission signal during a test to check the normality of the connection between the signal processing LSI and the transmitting analog IC and the normality of the connection between the receiving analog IC and the signal processing LSI; an intensity monitor unit configured to detect the intensity of the signal received from the receiving analog IC during the test; and a first control unit configured to control the first and second switches so that during the test, the intensity monitor terminal of the driver circuit is connected to the input terminal of the level conversion circuit and the output terminal of the level conversion circuit is connected to the gain control terminal of the transimpedance amplifier, and the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal strength has the same frequency component as the intensity change of the test signal.

[0083] (Supplementary Note 8) In the inspection system described in any one of Supplementary Notes 5 to 7, the inspection device further includes a second control unit configured to output, during the inspection, a gain control signal whose intensity changes at a frequency different from the frequency of the intensity change of the inspection signal to a gain control terminal of the driver circuit, and when the detected signal intensity has the same frequency component as the intensity change of the inspection signal and the same frequency component as the intensity change of the gain control signal, the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal, and that the connection of the gain control terminal of the driver circuit is also normal. [Industrial Applicability]

[0084] The present invention can be applied to a technique for inspecting an optical transmitting and receiving module. [Explanation of symbols]

[0085] 1, 1a to 1c...optical transmitting and receiving module, 2, 2b...signal processing LSI, 3...transmitting analog IC, 4...receiving analog IC, 5...optical chip, 6, 93...level conversion circuit, 7, 8, 94, 95...switch, 9, 9a to 9e...inspection device, 20...DAC, 21...ADC, 22, 96...inspection signal output unit, 23, 97...intensity monitor unit, 30...driver circuit, 40...transimpedance amplifier, 50...optical transmitting device, 51...optical receiving device, 90...control unit, 91...inspection unit, 92...gain control unit.

Claims

1. an optical chip including an optical transmitting device and an optical receiving device; a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmission signal; a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier; a signal processing LSI configured to output the transmission signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a reception signal; a level conversion circuit configured to convert the intensity monitor signal output from the driver circuit into a level that matches the gain control signal of the transimpedance amplifier; a first switch provided between an intensity monitor terminal of the driver circuit and an input terminal of the level conversion circuit; an output terminal of the level conversion circuit and a gain control terminal of the transimpedance amplifier; and a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier.

2. 2. The optical transceiver module according to claim 1, The signal processing LSI includes: an inspection signal output unit configured to output, to the transmitting analog IC, an inspection signal having a frequency lower than that of the transmission signal and whose signal strength is periodically changed, when inspecting whether the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI is normal; an intensity monitor configured to detect the intensity of a signal received from the receiving analog IC during the inspection;

3. an optical transceiver module according to claim 2; an inspection device for the optical transceiver module, the testing device includes a first control unit configured to control the first and second switches so that, during the testing, an intensity monitor terminal of the driver circuit is connected to an input terminal of the level conversion circuit, and an output terminal of the level conversion circuit is connected to a gain control terminal of the transimpedance amplifier; The inspection system is characterized in that the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the inspection signal.

4. 4. The inspection system according to claim 3, the testing device further includes a second control unit configured to output, during testing, to a gain control terminal of the driver circuit a gain control signal whose intensity changes at a frequency different from a frequency of the intensity change of the testing signal; When the detected signal strength has the same frequency components as the strength change of the inspection signal and the same frequency components as the strength change of the gain control signal, the strength monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal, and that the connection of the gain control terminal of the driver circuit is also normal.

5. an optical transceiver module; an inspection device for the optical transceiver module, The optical transceiver module comprises: an optical chip including an optical transmitting device and an optical receiving device; a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmission signal; a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier; a signal processing LSI configured to output the transmission signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a reception signal; The signal processing LSI includes: an inspection signal output unit configured to output, to the transmitting analog IC, an inspection signal having a frequency lower than that of the transmission signal and whose signal strength is periodically changed, when inspecting whether the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI is normal; an intensity monitor configured to detect the intensity of a signal received from the receiving analog IC during the test; The inspection device includes: a level conversion circuit configured to convert the intensity monitor signal output from the driver circuit into a level that matches the gain control signal of the transimpedance amplifier; a first switch provided between an intensity monitor terminal of the driver circuit and an input terminal of the level conversion circuit; a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier; a first control unit configured to control the first and second switches so that, during the inspection, an intensity monitor terminal of the driver circuit is connected to an input terminal of the level conversion circuit, and an output terminal of the level conversion circuit is connected to a gain control terminal of the transimpedance amplifier; The inspection system is characterized in that the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the inspection signal.

6. an optical transceiver module according to claim 1; an inspection device for the optical transceiver module, The inspection device includes: an inspection signal output unit configured to output, to the signal processing LSI, an inspection signal whose signal strength is periodically changed at a frequency lower than that of the transmission signal, during an inspection to check the normality of the connection between the signal processing LSI and the transmission analog IC and the normality of the connection between the reception analog IC and the signal processing LSI; an intensity monitor configured to detect the intensity of a signal received from the signal processing LSI during the inspection; a first control unit configured to control the first and second switches so that, during the inspection, an intensity monitor terminal of the driver circuit is connected to an input terminal of the level conversion circuit, and an output terminal of the level conversion circuit is connected to a gain control terminal of the transimpedance amplifier; the signal processing LSI outputs the test signal from the test signal output unit to the transmitting analog IC, and outputs the received signal from the receiving analog IC to the intensity monitor unit; The inspection system is characterized in that the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the inspection signal.

7. an optical transceiver module; an inspection device for the optical transceiver module, The optical transceiver module comprises: an optical chip including an optical transmitting device and an optical receiving device; a transmitting analog IC configured to drive the optical transmitting device by a driver circuit in response to a transmission signal; a receiving analog IC configured to amplify a signal output from the optical receiving device by a transimpedance amplifier; a signal processing LSI configured to output the transmission signal to the transmitting analog IC and process the signal amplified by the receiving analog IC to obtain a reception signal; The inspection device includes: a level conversion circuit configured to convert the intensity monitor signal output from the driver circuit into a level that matches the gain control signal of the transimpedance amplifier; a first switch provided between an intensity monitor terminal of the driver circuit and an input terminal of the level conversion circuit; a second switch provided between the output terminal of the level conversion circuit and the gain control terminal of the transimpedance amplifier; an inspection signal output unit configured to output, to the signal processing LSI, an inspection signal whose signal strength is periodically changed at a frequency lower than that of the transmission signal, during an inspection to check the normality of the connection between the signal processing LSI and the transmission analog IC and the normality of the connection between the reception analog IC and the signal processing LSI; an intensity monitor configured to detect the intensity of a signal received from the signal processing LSI during the inspection; a first control unit configured to control the first and second switches so that, during the inspection, an intensity monitor terminal of the driver circuit is connected to an input terminal of the level conversion circuit, and an output terminal of the level conversion circuit is connected to a gain control terminal of the transimpedance amplifier; the signal processing LSI outputs the inspection signal from the inspection signal output unit to the transmitting analog IC, and outputs the received signal from the receiving analog IC to the intensity monitor unit of the inspection device; The inspection system is characterized in that the intensity monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal when the detected signal intensity has the same frequency component as the intensity change of the inspection signal.

8. 8. The inspection system according to claim 5, the testing device further includes a second control unit configured to output, during testing, to a gain control terminal of the driver circuit a gain control signal whose intensity changes at a frequency different from a frequency of the intensity change of the testing signal; When the detected signal strength has the same frequency components as the strength change of the inspection signal and the same frequency components as the strength change of the gain control signal, the strength monitor unit determines that the connection between the signal processing LSI and the transmitting analog IC and the connection between the receiving analog IC and the signal processing LSI are normal, and that the connection of the gain control terminal of the driver circuit is also normal.

Images