JP6146022B2 - Optical signal receiving apparatus and signal receiving method thereof - Google Patents

Description

  The present invention relates to an optical signal receiving apparatus, and more particularly to a switching function according to an optical signal reception state.

  With the development of information communication, the importance of optical communication has increased and related technologies have been actively developed. In order to maintain communication quality, it is necessary to transmit signals as correctly as possible, but there are various factors of signal degradation on the transmission path. Therefore, the importance of a technique for suppressing signal degradation as much as possible is high. In order to suppress the influence of signal degradation on the transmission line, it is conceivable to appropriately grasp whether the signal being transmitted / received is good and to correct the signal when the signal degradation is large. For such a purpose, a transmission device for a communication signal such as an optical signal is provided with a signal quality monitoring function and a signal correction function. On the other hand, the use of various devices for signal monitoring and correction may increase the size of the transmission device and increase power consumption. Therefore, a balance between the maintenance of signal quality and the efficiency in use such as the suppression of the installation area and power consumption of the transmission apparatus is also required.

  As a technique for monitoring signal quality, for example, there is a technique disclosed in Patent Document 1. Patent Document 1 discloses a technique for selecting an optimum receiving system from a plurality of receiving systems in a diversity receiving apparatus. In Patent Document 1, a jitter pulse is generated from a phase shift of a reproduction clock generated from a received signal, and the jitter pulse is measured. In addition, the jitter pulse is measured every unit time, and data processing is performed in consideration of the occurrence of the jitter pulse in the time zone before and after the occurrence of the jitter pulse. There is a high probability that a bit error will occur before and after the occurrence of a jitter pulse. Therefore, since it is possible to make an appropriate determination by adding and determining information on the occurrence of a bit pulse in the time zone before and after the actual occurrence of a jitter pulse, it is possible to select a system with a good reception state. Yes.

  As a technique related to signal quality, Patent Document 2 discloses a technique of switching and using circuits having different signal correction functions. Patent Document 2 discloses a technique related to an optical transmission device having a switching circuit between a 2R operation mode and a 3R operation mode. The optical transmission device of Patent Document 2 differs depending on the 2R operation mode having an equalization (Reshaping) function and an identification reproduction (Regenerating) function, and a 3R operation mode further having a timing reproduction (Retiming) function in the function of the 2R operation mode. A circuit of two operation modes is provided. The optical transmission device has a function of transmitting a signal from an appropriate side of either a 2R operation circuit or a 3R operation circuit. In the optical transmission device of Patent Document 2, switching between the 2R operation mode and the 3R operation mode is output by a mode select signal, and a signal subjected to appropriate signal correction is transmitted.

JP-A-8-32499 Japanese Utility Model Publication No.59-17659

  However, the technique disclosed in Patent Document 1 has the following problems. In Patent Document 1, an appropriate transmission system is selected by measuring jitter of a signal and analyzing and using the result by a predetermined method. However, the handling of the signal when communication is continued after selecting the transmission system is not disclosed, and it is applicable when the signal has deteriorated enough to be distorted or require timing correction. I can't. In Patent Document 2, a signal is transmitted by selecting a circuit in 2R operation and 3R operation. The selection depends on the input signal. Therefore, it is insufficient as a technique for correcting signal distortion and timing appropriately according to the situation, such as when signal deterioration becomes large.

  An object of the present invention is to obtain an optical signal receiver capable of monitoring an optical signal reception state and selecting an appropriate circuit based on the monitoring result.

  In order to solve the above problems, an optical signal receiving apparatus of the present invention includes a photoelectric conversion means, a first circuit, a second circuit, a signal switching means, a timing recovery means, a signal detection means, and a control means. And. The photoelectric conversion means converts the input optical signal into an electrical signal. The signal switching means performs switching so that the electric signal is input to either the first circuit or the second circuit. The timing recovery means is provided in the second circuit, performs timing recovery of the input signal, and outputs it. The signal detection means detects the power of the electrical signal before the signal switching means. The control means determines whether or not the power of the electric signal detected by the signal detection means is smaller than a predetermined reference value when the signal switching means selects the signal input to the first circuit. When the control means determines that the power of the electric signal has become smaller than a predetermined reference value, the control means controls the signal switching means so that the signal is input to the second circuit.

  The signal receiving method of the present invention converts an input optical signal into an electrical signal, detects the power of the electrical signal, and compares the detected power of the electrical signal with the first predetermined reference value. . Whether the power of the detected electric signal is smaller than the first predetermined reference value when the electric signal is set to be input to the first circuit that does not pass through the second circuit including the timing recovery means. to decide. If it is determined that the power of the detected electrical signal is smaller than the first predetermined reference value, the circuit to which the electrical signal is input is switched from the first circuit to the second circuit.

  In the present invention, when there is a possibility that the strength of the received signal is weak and the degree of deterioration is large, it is possible to automatically switch to a circuit having a timing reproduction function based on the detection result of the signal. As a result, it is possible to perform signal correction using a circuit necessary for signal correction only when necessary, and it is possible to maintain both signal quality and improve efficiency.

It is a figure which shows the outline | summary of a structure of the 1st Embodiment of this invention. It is a figure which shows the operation | movement flow in the 1st Embodiment of this invention. It is a figure which shows the operation example in the 1st Embodiment of this invention. It is a figure which shows the example of the signal state in the 1st Embodiment of this invention. It is a figure which shows the outline | summary of a structure of the 2nd Embodiment of this invention.

  A first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 shows an outline of the configuration of the optical signal receiving apparatus of this embodiment. The optical signal receiving apparatus of this embodiment includes an optical signal light receiving unit 11, a transimpedance amplifier 12, a limiting amplifier 13, and a changeover switch unit 14. The optical signal receiving device includes a clock data recovery unit 15, a transistor unit 16, a received light power detection unit 17, a signal amplitude detection unit 18, and a control unit 19. The clock data recovery unit 15 includes a clock data recovery circuit 20, a jitter detection unit 21, and a power supply control unit 22.

  The optical signal light receiving unit 11 includes a photodiode, and has a function of converting an input optical signal into a current and outputting it as an electric signal. The transimpedance amplifier 12 has a function of performing an impedance conversion for converting an electric signal based on a current into a voltage and a voltage amplification and outputting the voltage. The limiting amplifier 13 has a function of adjusting and outputting the voltage of the input electric signal to the set value range of the subsequent circuit. The changeover switch unit 14 includes a switch element, and has a function of switching the switch element and switching the path of the electric signal based on an instruction from the control unit 19. The change-over switch unit 14 has a function of switching the path to either a circuit that directly sends an electric signal to the output side, which is a subsequent stage of the apparatus, or a circuit that sends the electric signal to the output side via the clock data recovery unit 15 It has an element. In the present embodiment, a path for directly sending an electric signal to the output side is called a first circuit, and a path passing through the clock data recovery unit 15 is called a second circuit.

  The clock data recovery unit 15 has a timing recovery function that extracts a clock of a signal, adjusts the timing, and outputs the result. The clock data recovery unit 15 includes a clock data recovery circuit 20 formed of a flip-flop circuit or the like, a jitter detection unit 21 that detects signal jitter, and a power supply control unit 22. The jitter detection unit 21 has a function of measuring the jitter of the electrical signal input to the clock data recovery unit 15 and outputting the result to the control unit 19. The power supply control unit 22 controls the power supply of the clock data recovery unit 15 in accordance with an instruction from the control unit 19. The power supply control unit 22 turns on the power of the clock data recovery unit 15 in accordance with an instruction from the control unit 19. The power-off state in the clock data recovery unit 15 is not a state in which the power is completely shut off, but may be a standby state in which a weak power is maintained.

  The transistor unit 16 includes a transistor element, and is configured such that a current is sent to the light receiving power detection unit 17 by a change in the potential of the photodiode when the optical signal receiving unit 11 receives an optical signal. The received light power detection unit 17 detects the current value converted by the transistor unit 16 and corresponding to the intensity of the received light, converts it to a voltage, and outputs it to the control unit 19. The received light power detector 17 detects the average intensity of the optical signal. The signal amplitude detector 18 measures the amplitude of the voltage of the electric signal output from the limiting amplifier and outputs it to the controller 19.

  The control unit 19 has a function of determining the reception state of the optical signal based on the information of the measurement values received from the received light power detection unit 17, the signal amplitude detection unit 18, and the jitter detection unit 21. The control unit 19 stores in advance a current-voltage characteristic in the transistor unit 16, a characteristic of the photodiode of the optical signal light receiving unit 11, and a predetermined reference value that is a threshold value for determining the reception state of the optical signal. . The control unit 19 calculates the intensity of the received optical signal based on each stored data and the measured value, and compares it with a predetermined reference value to determine the optical signal reception state. The control unit 19 also has a function of controlling the switch element of the changeover switch unit 14 and the power supply control unit 22 of the clock data recovery unit 15 based on the determination result of the optical signal reception state.

  The operation of the optical signal receiving apparatus of this embodiment will be described. It is assumed that an optical signal is input to the optical signal light receiving unit 11. When an optical signal is input to the optical signal light receiving unit 11, the light is converted into an electric current by a photodiode which is a photoelectric conversion element and output as an electric signal. The electrical signal output from the optical signal light receiving unit 11 is sent to the transimpedance amplifier 12. In addition, a voltage is applied to the gate of the transistor element in the transistor portion 16 due to a potential difference generated in the photodiode when an optical signal is input. When a voltage is applied to the gate and the gate is in an open state, a current from a power source provided in the transistor unit 16 flows to the received light power detection unit 17. The received light power detector 17 measures the value of the input current, converts it into a voltage, and outputs it to the controller 19.

  The electrical signal input to the transimpedance amplifier 12 is converted from an electrical signal based on current to an electrical signal based on voltage, amplified and output. The electrical signal output from the transimpedance amplifier 12 is sent to the limiting amplifier 13. The limiting amplifier 13 adjusts the amplitude of the voltage of the input electric signal within a certain range. The electrical signal output from the limiting amplifier 13 is sent to the changeover switch unit 14. In addition, the electric signal output from the limiting amplifier 13 is branched and input to the signal amplitude detector 18. The signal amplitude detection unit 18 measures the amplitude of the voltage of the input electric signal and sends the measurement result to the control unit 19.

  The electrical signal input to the changeover switch unit 14 is sent to either the first circuit or the second circuit by switching the switch element. When sent to the first circuit, the electrical signal is output to the subsequent stage as it is. When the signal is sent to the second circuit, the electric signal is input to the clock data recovery unit 15. The electrical signal input to the clock data recovery unit 15 is corrected in timing by the clock data recovery circuit 20 and output in a state where the timing is recovered. The electrical signal output from the clock data recovery unit 15 is sent to the subsequent stage in the same manner as the electrical signal of the first circuit. When an electrical signal is input to the second circuit, the electrical signal is branched and also input to the jitter detector 21. The jitter detector 21 measures the jitter of the input electrical signal and sends the measurement result to the power supply controller 22.

  The control unit 19 determines the reception state of the optical signal based on information such as measurement values sent from the light reception power detection unit 17, the signal amplitude detection unit 18, and the jitter detection unit 21, and switches the changeover switch unit 14 and the clock data. The power control unit 22 of the recovery unit 15 is controlled. It is assumed that the first circuit side is selected in the changeover switch unit 14. At this time, the power supply control unit 22 controls the clock data recovery unit 15 in an off state. The control unit 19 compares the measurement values sent from the light reception power detection unit 17 and the signal amplitude detection unit 18 or values obtained by converting the measurement values with predetermined reference values that are set. When both of the measured values sent from the light reception power detection unit 17 and the signal amplitude detection unit 18 are equal to or greater than a predetermined reference value, the control unit 19 determines that the state of the optical signal is good and determines the first. Continue to select the circuit. When any one of the measured values sent from the received light power detection unit 17 or the signal amplitude detection unit 18 is smaller than a predetermined reference value, the control unit 19 determines that the reception state of the optical signal is bad. When the control unit 19 determines that the optical signal reception state is poor, the control unit 19 sends an instruction to the switch unit 14 to switch the switch element and switch the input of the electric signal to the second circuit side. In addition, when the control unit 19 sends an instruction to switch to the second circuit side to the changeover switch unit 14, the control unit 19 sends an instruction to turn on the power to the power supply control unit 22 of the clock data recovery unit 15. When the changeover switch unit 14 receives an instruction to switch to the second circuit side, the changeover switch unit 14 switches the switch element to input an electric signal input to the second circuit side. Further, when the power supply control unit 22 of the clock data recovery unit 15 receives an instruction to turn on the power, it supplies power to each part of the clock data recovery unit 15 and puts it into an operating state.

  Next, a case will be described in which the selector switch unit 15 is selected to send an electrical signal to the second circuit side. At this time, the power supply control unit 22 performs control to supply power to each part of the clock data recovery unit 15 and turn it on. The timing of the electric signal input in the clock data recovery circuit 20 is recovered and output. ing. The jitter detector 21 measures the jitter of the input electrical signal and outputs the measurement result to the controller 19. The control unit 19 compares the measurement values sent from the received light power detection unit 17, the signal amplitude detection unit 18 and the jitter detection unit 21 or the values obtained by converting the measurement values with predetermined set reference values. The control unit 19 has a measurement value or the like at the received light power detection unit 17 and the signal amplitude detection unit 18 that is equal to or greater than a predetermined reference value, and a jitter detection value at the jitter detection unit 22 is equal to or less than the predetermined reference value. It is determined that the reception state of the optical signal is good. When the control unit 19 determines that the light receiving state of the optical signal is good, the control unit 19 sends an instruction to the changeover switch unit 14 to switch the input of the electric signal from the second circuit to the first circuit. In addition, when the control unit 19 sends an instruction to switch the input of the electrical signal from the second circuit to the first circuit to the changeover switch unit 14, the power is turned off to the power control unit 22 of the clock data recovery unit 15. To send instructions. When receiving the instruction to turn off the power supply control unit 22, the power supply control unit 22 stops the power supply to each part of the clock data recovery unit 15. Further, the control unit 19 detects the optical signal when the measured value of the light reception power detection unit 17 or the signal amplitude detection unit 18 is smaller than a predetermined reference value, or when the jitter in the jitter detection unit 21 is larger than the predetermined reference value. It is determined that the reception state of is bad, that is, not good. When the control unit 19 determines that the light receiving state of the optical signal is not good, the control unit 19 continues to input the electric signal to the second circuit side in the changeover switch unit 14. When the clock data recovery unit 15 turns off the power, the power control unit 22 supplies a weak power without completely shutting off the power supply to each part and controls it as a standby state in preparation for startup. You can also In the optical signal receiving apparatus of this embodiment, when a signal is input to the first circuit, it corresponds to a 2R operation, and when a signal is input to the second circuit, it corresponds to a 3R operation.

  In FIG. 2, in this embodiment, either a case where a signal is input to the first circuit and output to the subsequent stage without performing timing recovery, or a case where the signal is input to the second circuit and timing recovery is performed is performed. An outline of the flow for determining whether to select is shown. With reference to FIG. 2, a flow for determining which of the first circuit and the second circuit is selected will be described.

  The control unit 19 compares the light reception power detected by the light reception power detection unit 17 with a predetermined reference value (step 101). When the received light power is equal to or higher than the predetermined reference value (Yes in step 102), the control unit 19 compares the amplitude of the signal detected by the signal amplitude detection unit 18 with the predetermined reference value (step 103). When the amplitude of the signal is equal to or greater than the predetermined reference value (Yes in Step 104), if the signal is input to the first circuit side (Yes in Step 105), the control unit 19 goes directly to the first circuit side. The signal is continuously input (step 109). When a signal is input to the first circuit side, the timing recovery of the signal is not performed. When no signal is input to the first circuit side in step 105, that is, when a signal is input to the second circuit side (No in step 105), the control unit 19 is detected by the jitter detection unit 21. Then, the jitter is compared with a predetermined reference value (step 106). When the jitter is equal to or less than the predetermined reference value (Yes in Step 107), the control unit 19 controls the changeover switch unit 14 to switch the switch element (Step 108). By switching the switch element in step 108, the signal is input to the first circuit side and output to the subsequent stage without performing timing recovery (step 109). Further, when the jitter is larger than the predetermined reference value in Step 107 (No in Step 107), the signal is input to the second circuit side, the timing recovery is performed, and the operation of outputting to the subsequent stage is continued (Step 112). ).

  When it is determined in step 102 that the received light power is smaller than the predetermined reference value (No in step 102), or when it is determined in step 104 that the signal amplitude is smaller than the predetermined reference value (No in step 104). ), Proceed to step 110. In step 110, the control unit 19 determines whether a signal is input to the second circuit side. When a signal is input to the second circuit side (Yes in step 110), the control unit 19 continues the operation of inputting the signal to the second circuit side, performing timing recovery, and outputting to the subsequent stage ( Step 112). When no signal is input to the second circuit side in step 110 (No in step 110), the control unit 19 controls the changeover switch unit 14 to switch the switch element (step 111). When the switching element is switched, the signal is input to the second circuit side, the timing is recovered, and output to the subsequent stage. Further, the order of the determination of the received light power in step 102 and the determination of the amplitude of the signal in step 104 can be reversed.

  FIG. 3 summarizes the relationship between the presence / absence of the above operating state transition and the measured value. When the operation without timing regeneration, that is, the 2R operation is performed, the 2R operation is continued when the received light power and the signal amplitude are equal to or larger than the reference value. When either the received light power or the signal amplitude becomes smaller than a predetermined reference value during the 2R operation, the operation shifts to the 3R operation for performing timing recovery. When the 3R operation is performed, the operation of the 3R is continued when either one of the received light power or the amplitude of the signal is smaller than the predetermined reference value or when the jitter is smaller than the predetermined reference value. When the 3R operation is performed, when the light reception power and the signal amplitude are larger than the predetermined reference value and the signal jitter is smaller than the predetermined reference value, the timing reproduction is stopped and the 2R operation is performed. And migrate.

  FIG. 4 shows an image of a signal in the optical signal receiving apparatus. When the optical signal transmitted from the optical transmitter passes through a transmission path with little occurrence of signal distortion or the like, there is little signal degradation as shown in the upper part of FIG. In the upper part of FIG. 4 where the signal distortion is small, the optical signal is converted into the electric signal, and the signal is output to the subsequent stage without performing the timing recovery. Further, when the signal passes through a transmission path where signal distortion or the like is likely to occur, signal degradation such as an increase in the timing variation of the optical signal occurs as shown in the lower part of FIG. In that case, in addition to the conversion from the optical signal to the electric signal, the timing of the signal is adjusted by the clock data recovery circuit shown as CDR in FIG. 4 and output to the subsequent stage. The optical signal receiving apparatus of the present embodiment can perform the operations shown in the upper and lower stages of FIG. 4 by switching the circuit for inputting signals according to the optical signal reception state. Therefore, it is not necessary for the operator to monitor the signal reception state and perform a switching operation, and it is not necessary to prepare a plurality of devices according to the operation mode, so that the installation space can be reduced and convenience is improved.

  In the optical signal receiving apparatus according to the present embodiment, the control unit 19 determines the reception state of the optical signal and switches the switch element of the changeover switch unit 14, thereby confirming whether the timing recovery of the signal in the clock data recovery circuit 20 has been performed. Switching is in progress. Further, when the clock data recovery circuit 20 is not used, the control unit 19 performs control to turn off the power supply. When the control unit 19 determines and controls the reception state of the optical signal, it automatically shifts to an operation using the clock data recovery circuit 15 when the reception state of the optical signal is poor and timing recovery is necessary. Signal quality can be maintained. Also, when the optical signal reception state is good and timing recovery is not necessary, the power consumption of the clock data recovery circuit 15 can be suppressed by automatically turning it off according to the judgment of the control unit 19. it can. As a result, while maintaining the quality of the signal, it is possible to suppress power consumption without requiring an operator's operation, and the efficiency can be improved.

  A second embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 shows an outline of the configuration of the optical signal receiving apparatus of this embodiment.

  The optical signal receiving apparatus according to the present embodiment includes a photoelectric conversion unit 31, a first circuit 32, a second circuit 33, a signal switching unit 34, a timing reproduction unit 35, a signal detection unit 36, and a control unit 37. And. The photoelectric conversion means 31 converts the input optical signal into an electrical signal. The signal switching unit 34 performs switching so that an electric signal is input to either the first circuit 32 or the second circuit 33. The timing recovery means 35 is provided in the second circuit 33, performs timing recovery of the input signal, and outputs it. The signal detection means 36 detects the power of the electrical signal before the signal switching means 34. When the signal switching means 34 selects the signal input to the first circuit 32, the control means 37 has detected whether the power of the electrical signal detected by the signal detection means 36 has become smaller than a predetermined reference value. Judging. When the control unit 37 determines that the power of the electric signal is smaller than a predetermined reference value, the control unit 37 controls the signal switching unit 34 so that the signal is input to the second circuit 33.

  When the optical signal receiving apparatus of this embodiment is used, when there is a possibility that the intensity of the received signal is weak and the degree of deterioration is large, a circuit having a timing reproduction function based on the detection result of the signal is provided. It can be switched automatically. As a result, since the signal can be corrected only when necessary, it is possible to maintain both signal quality and improve efficiency.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

  [Appendix 1] Photoelectric conversion means for converting an input optical signal into an electric signal, a first circuit and a second circuit to which the electric signal is input, and the electric signal is the first circuit or the first circuit. Signal switching means for switching so as to be input to any one of the two circuits, timing recovery means provided in the second circuit for performing timing recovery of the input electrical signal and outputting, and the signal Detected by the signal detection means when the signal detection means for detecting the power of the electrical signal in the previous stage is also selected by the switching means, and when the signal input to the first circuit is selected by the signal switching means. Control means for controlling the signal switching means so that the signal is input to the second circuit when it is determined that the power of the electric signal is smaller than a first predetermined reference value; Optical signal receiving apparatus characterized by comprising.

  [Supplementary Note 2] A light receiving power detecting means for detecting the light receiving power of the input optical signal is further provided, and the control means controls the signal switching means based on the detection result of the light receiving power in the light receiving power detecting means. The control means has a second light receiving power of the optical signal detected by the light receiving power detecting means when the signal switching means selects the signal input to the first circuit. The optical signal receiving apparatus according to appendix 1, wherein the signal switching unit is controlled so that a signal is input to the second circuit when it is determined that the signal is smaller than a predetermined reference value.

  [Supplementary Note 3] Current-voltage conversion means for converting the electric signal output from the photoelectric conversion means from a current signal to a voltage signal, amplifying and outputting, and the amplitude of the voltage signal from the current-voltage conversion means Amplitude adjustment means for adjusting and outputting within a predetermined range, and the signal detection means measures the output signal from the amplitude adjustment means to detect the power of the electrical signal. The optical signal receiver according to any one of Appendix 1 or 2.

[Appendix 4] The timing regeneration means further includes power control means for controlling the power supply of the timing regeneration means, and the control means further comprises means for controlling the power control means,
The control means performs control for turning on the power of the timing recovery means when the signal switching means is switched from the first circuit to the second circuit. An optical signal receiving device according to claim 1.

  [Supplementary Note 5] The timing recovery means further includes jitter detection means for detecting a jitter amount of the signal input to the timing recovery means, and the control means is configured to select the second circuit in the signal switching means. The jitter amount in the jitter detecting means is smaller than a third predetermined reference value, and the power of the signal detected in the signal detecting means is larger than the first predetermined reference value, and When the light receiving power of the optical signal detected by the light receiving power detecting means is determined to be larger than the second predetermined reference value, the signal switching means is configured to input a signal to the first circuit. 4. The optical signal receiver according to any one of appendices 1 to 3, wherein control is performed.

  [Appendix 6] The timing regeneration means further includes power supply control means for controlling the power supply of the timing regeneration means, the control means further includes means for controlling the power supply control means, and the control means includes the signal switching means. 6. The optical signal receiving apparatus according to appendix 5, wherein when the means is switched from the second circuit to the first circuit, the timing regeneration means is controlled to be turned off.

  [Appendix 7] The input optical signal is converted into an electrical signal, the power of the electrical signal is detected, the detected power of the electrical signal is compared with a first predetermined reference value, and the electrical signal is compared. When the signal is set to be input to the first circuit that does not pass through the second circuit having the timing recovery means, the detected power of the electric signal becomes smaller than the first predetermined reference value. If it is determined that the signal is received, the circuit to which the electrical signal is input is switched from the first circuit to the second circuit.

  [Appendix 8] The setting is such that the received light power of the input optical signal is detected, the received light power is compared with a second predetermined reference value, and the electrical signal is input to the first circuit. If it is determined that the received light power is smaller than the second predetermined reference value, the circuit to which the electric signal is input is switched from the first circuit to the second circuit. The optical signal receiving method according to appendix 7.

  [Supplementary Note 9] The electrical signal converted from the optical signal is converted from a current signal to a voltage signal, amplified and output, and the amplitude of the amplified voltage signal is adjusted within a predetermined range. Output as a signal, measure the amplitude adjustment signal to obtain a measurement result of the power of the electrical signal, and input the amplitude adjustment signal as the electrical signal to the first circuit or the second circuit by switching the circuit 9. The optical signal receiving method according to any one of appendix 7 or 8, wherein:

  [Supplementary Note 10] The supplementary notes 7 to 9 are characterized in that when the circuit to which the amplitude adjustment signal is input is switched from the first circuit to the second circuit, the timing recovery means is turned on. An optical signal receiving method according to any one of the above.

  [Supplementary Note 11] When the jitter amount of the signal input to the timing reproduction means is detected and the amplitude adjustment signal is input to the second circuit, the jitter amount is a third predetermined reference value. If it is determined that the amplitude adjustment signal is smaller, the amplitude of the amplitude adjustment signal is greater than the first predetermined reference value, and the received light power is greater than the second predetermined reference value, the amplitude adjustment signal is 10. The optical signal receiving method according to any one of appendices 7 to 9, wherein an input circuit is switched from the second circuit to the first circuit.

  [Supplementary Note 12] The supplementary note 11 is characterized in that when the circuit to which the amplitude adjustment signal is input is switched from the second circuit to the first circuit, the timing recovery means is turned off. Optical signal reception method.

  The present invention can be used in an optical signal receiving apparatus, and in particular, can be used in an optical signal receiving apparatus that is used by switching the presence or absence of correction depending on the signal reception state.

DESCRIPTION OF SYMBOLS 11 Optical signal light reception part 12 Transimpedance amplifier 13 Limiting amplifier 14 Changeover switch part 15 Clock data recovery part 16 Transistor part 17 Light reception power detection part 18 Signal amplitude detection part 19 Control part 20 Clock data recovery circuit 21 Jitter detection part 22 Power supply control Unit 31 Photoelectric conversion means 32 First circuit 33 Second circuit 34 Signal switching means 35 Timing reproduction means 36 Signal detection means 37 Control means 101-112 Step of operation state determination

Claims (10)

Photoelectric conversion means for converting an input optical signal into an electrical signal;
A light receiving power detecting means for detecting a light receiving power of the optical signal;
Signal amplitude detection means for measuring the amplitude of the electrical signal;
A first circuit that directly outputs the input electrical signal when the electrical signal is input;
A second circuit having timing recovery means for performing timing recovery of the input electrical signal and outputting it when the electrical signal is input;
A signal switching means for switching a switch so that the electrical signal is input to either the first circuit or the second circuit;
Control means for controlling switching of the switch of the signal switching means based on the light receiving power of the optical signal detected by the light receiving power detection means and the amplitude of the electrical signal measured by the signal amplitude detection means. ,
The control means is configured such that when the light reception power of the optical signal detected by the light reception power detection means is smaller than a second predetermined reference value, the electrical signal is input to the first circuit;
When the light reception power of the optical signal detected by the light reception power detection means is greater than the second predetermined reference value and the amplitude of the electrical signal is smaller than the first predetermined reference value, the first circuit The switching of the switch of the signal switching means is controlled so that the electrical signal is input to the second circuit instead of the first circuit when the electrical signal is input to the first circuit. An optical signal receiver. Current-voltage conversion means for converting the electric signal output from the photoelectric conversion means from a current signal to a voltage signal, amplifying and outputting the voltage signal;
Amplitude adjustment means for adjusting and outputting the amplitude of the voltage signal from the current-voltage conversion means within a predetermined range; and
2. The optical signal receiving apparatus according to claim 1, wherein the signal amplitude detecting unit measures the output signal from the amplitude adjusting unit and detects the amplitude of the electric signal. The timing regeneration means further comprises power control means for controlling the power supply of the timing regeneration means,
The control means further comprises means for controlling the power supply control means,
3. The control unit according to claim 1, wherein when the signal switching unit is switched from the first circuit to the second circuit, the control unit performs control to turn on the power of the timing recovery unit. 2. An optical signal receiving device according to 1. The timing recovery means further comprises jitter detection means for detecting the jitter amount of the signal input to the timing recovery means,
When the second circuit is selected in the signal switching unit, the control unit detects that the jitter amount in the jitter detection unit is smaller than a third predetermined reference value and is detected in the signal amplitude detection unit. It is determined that the amplitude of the received signal is greater than the first predetermined reference value and that the light reception power of the optical signal detected by the light reception power detection means is greater than the second predetermined reference value. 3. The optical signal receiving apparatus according to claim 1, wherein the signal switching unit is controlled so that a signal is input to the first circuit. The photoelectric conversion means includes a photodiode that converts the optical signal into the electrical signal,
The light reception power detection means detects the light reception power of the optical signal by measuring a current supplied through a transistor element that is turned on by an electrical change generated in the photodiode when the optical signal is input. The optical signal receiving apparatus according to claim 1, wherein Photoelectric conversion means for converting an input optical signal into an electrical signal;
A light receiving power detecting means for detecting a light receiving power of the optical signal;
Signal amplitude detection means for measuring the amplitude of the electrical signal;
A first circuit that directly outputs the input electrical signal when the electrical signal is input;
A second circuit having timing recovery means for performing timing recovery of the input electrical signal and outputting it when the electrical signal is input;
A signal switching means for switching a switch so that the electrical signal is input to either the first circuit or the second circuit;
Control means for controlling switching of the switch of the signal switching means based on the light receiving power of the optical signal detected by the light receiving power detection means and the amplitude of the electrical signal measured by the signal amplitude detection means. ,
The timing recovery means further comprises jitter detection means for detecting the jitter amount of the signal input to the timing recovery means,
When the second circuit is selected in the signal switching unit, the control unit detects that the jitter amount in the jitter detection unit is smaller than a third predetermined reference value and is detected in the signal amplitude detection unit. When it is determined that the amplitude of the received signal is greater than a first predetermined reference value and the light reception power of the optical signal detected by the light reception power detection means is greater than a second predetermined reference value The optical signal receiving apparatus controls the signal switching means so that a signal is input to the first circuit. Converts input optical signals into electrical signals,
Detecting the received light power of the optical signal;
Measuring the amplitude of the electrical signal;
When the electrical signal is input, a first circuit that directly outputs the input electrical signal; and when the electrical signal is input, the timing of the input electrical signal is reproduced and output. Switching of a switch for inputting the electrical signal to any one of the second circuits is controlled based on the light receiving power of the optical signal and the amplitude of the electrical signal ;
When the light receiving power of the optical signal is larger than a second predetermined reference value and the amplitude of the electric signal is smaller than a first predetermined reference value, the electric signal is input to the first circuit. In this case, the switch is controlled so that the electrical signal is input to the second circuit . The electrical signal converted from the optical signal is converted from a current signal to a voltage signal, amplified and output,
Adjust the amplitude of the amplified voltage signal within a predetermined range and output as an amplitude adjustment signal,
The optical signal receiving method according to claim 7, wherein the amplitude adjustment signal is measured to detect the amplitude of the electrical signal. Detecting the jitter amount of the electrical signal when the second circuit is selected in the switch;
The jitter amount is smaller than a third predetermined reference value, the amplitude of the electric signal is larger than the first predetermined reference value, and the light receiving power is larger than the second predetermined reference value. If it ’s big,
9. The optical signal receiving method according to claim 7, wherein a circuit to which the electric signal is input is switched from the second circuit to the first circuit. Converts input optical signals into electrical signals,
Detecting the received light power of the optical signal;
Measuring the amplitude of the electrical signal;
When the electrical signal is input, a first circuit that directly outputs the input electrical signal; and when the electrical signal is input, the timing of the input electrical signal is reproduced and output. Switching of a switch for inputting the electrical signal to any one of the second circuits is controlled based on the light receiving power of the optical signal and the amplitude of the electrical signal;
Detecting the jitter amount of the electrical signal when the second circuit is selected in the switch;
When the jitter amount is smaller than a third predetermined reference value, the amplitude of the electric signal is larger than a first predetermined reference value, and the received light power is larger than a second predetermined reference value. Judging
A method for receiving an optical signal, wherein the circuit to which the electrical signal is input is switched from the second circuit to the first circuit.

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