Optical receiver and optical transceiver module

Abstract

To accurately detect the input light intensity for each wavelength or channel and the total input light intensity by a WDM optical receiver.SOLUTION: An optical receiver holds, in a memory, information representing the relationship between the total input light intensity of WDM signals input to an optical amplifier and the gain of each wavelength of the optical amplifier, and until the total input light intensity converges, a processor repeats first calculation for identifying the gain for each wavelength with reference to the memory on the basis of a drive current value of the optical amplifier and an estimated value of the total input light intensity, second calculation for calculating the input light intensity of each wavelength input to the optical amplifier on the basis of the identified gain for each wavelength and the monitor value of the light intensity for each wavelength obtained by a monitor circuit, and third calculation for calculating the total input light intensity from the sum of the input light intensity of each wavelength.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an optical receiver and an optical transceiver module. [Background technology]

[0002] One of the technologies to cope with the increase in data traffic is wavelength division multiplexing (WDM) optical communication. WDM improves the transmission rate per optical fiber by multiplexing light of multiple wavelengths onto a single optical fiber. At the receiving end, the WDM signal may be amplified using a semiconductor optical amplifier (SOA) or similar before being separated into optical signals of each wavelength.

[0003] FIG. 1 is a diagram showing the configuration of an optical receiver RX with a built-in SOA for WDM communication equipment. Before being demultiplexed into individual wavelengths by an optical demultiplexer 112 (denoted as "O-Demux" in the figure), the received WDM signal is amplified by an SOA 111. The gain of the SOA 111 is determined by the drive current I SOA In addition, the total input optical power of the SOA111 (shown as "P TOTAL Therefore, a monitor photodetector (denoted as "mPD" in the figure) 114 is provided in front of the SOA 111 to detect the total input optical intensity of the SOA 111 (see, for example, Patent Document 1). In addition, a monitor circuit 151 is provided in the rear of the optical demultiplexer 112 to monitor the optical intensity of the signal of each wavelength (channel) detected by the photodetector (denoted as "mPD" in the figure) 113.

[0004] The processor 130 calculates the total input optical power P TOTAL and the drive current I SOABased on the above, the processor 130 refers to the gain table 141 and calculates the SOA gain for each channel. Based on the SOA gain for each channel and the monitor optical intensity for each channel, the processor 130 also calculates the input optical intensity for each channel to be input to the SOA 111. The input optical intensity for each channel is used for notifying the communication device of information, for internal control of the optical receiver RX, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-105221 Summary of the Invention [Problem to be solved by the invention]

[0006] For 100G QSFP modules over 40km, miniaturization is required, and there is a need to reduce the number of components required to obtain the input optical power for each channel.If the tap for branching at the input stage of the SOA and the monitor photodetector are not used, the input optical power for each channel cannot be determined correctly, making it difficult to control the optical receiver internally and to transmit accurate information to the communication device equipped with the optical receiver.

[0007] In one aspect of the invention, an optical receiver accurately detects the input optical power for each wavelength or channel of a WDM signal and the total input optical power. [Means for solving the problem]

[0008] In one embodiment, the optical receiver comprises: an optical amplifier that amplifies an optical signal in which a plurality of wavelengths are multiplexed; a current source for driving the optical amplifier; an optical demultiplexer that demultiplexes the optical signal amplified by the optical amplifier into individual wavelengths; a photodetector for detecting light of each of the demultiplexed wavelengths; a monitor circuit for monitoring the light intensity of each wavelength detected by the photodetector; a processor; Memory and and the memory holds information representing a relationship between a total input optical intensity of the optical signals input to the optical amplifier and a gain of the optical amplifier for each wavelength; The processor repeats the following calculations until the total input optical intensity converges: a first calculation to identify the gain for each wavelength by referring to the information stored in the memory based on the drive current value of the current source and the estimated value of the total input optical intensity; a second calculation to calculate the input optical intensity for each wavelength input to the optical amplifier based on the identified gain for each wavelength and the monitor value of the optical intensity for each wavelength obtained by the monitor circuit; and a third calculation to calculate the total input optical intensity from the sum of the input optical intensity for each wavelength. [Effects of the Invention]

[0009] In the optical receiver, the input optical power for each wavelength or channel of the WDM signal and the total input optical power can be detected with high accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a receiver incorporating an SOA for a WDM communication device. [Figure 2] 1 is a schematic diagram of an optical transceiver module including an optical receiver according to an embodiment; [Figure 3] FIG. 1 is a schematic diagram of an optical receiver. [Figure 4] 10 is a flowchart showing the processing of a processor of the optical receiver. [Figure 5] FIG. 10 is a diagram illustrating an example of a gain table. [Figure 6] 6 is a diagram showing, as a characteristic diagram, information described in a gain table of one channel (ch1) in FIG. 5. FIG. [Figure 7] 10A and 10B are diagrams showing experimental results of convergence of input light intensity detection error by repeated calculations. [Figure 8] 10 is a flowchart showing an example of calculating an initial value of the total SOA input light intensity. [Figure 9]10 is a diagram illustrating an example of calculation of an initial value for estimating the total SOA input light intensity. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] In an embodiment, the optical transceiver detects the input optical power and total input optical power for each wavelength or channel of a WDM signal accurately in a range exceeding 40 km (e.g., 80 km) of the optical transceiver module without using a monitoring mechanism upstream of the SOA of the optical receiver. Specifically, the SOA drive current information and the provisional total input optical power are used to calculate the SOA gain for each channel by referring to gain information. The input optical power and total input optical power for each channel incident on the SOA are calculated based on the calculated SOA gain for each channel and the monitoring results of the optical power after demultiplexing. The SOA gain for each channel is recalculated based on the calculated total input optical power, and the input optical power and total input optical power for each channel are calculated. This process is repeated to determine the convergence point of the estimated total input optical power of the WDM signal incident on the SOA.

[0012] 2 is a schematic diagram of an optical transceiver module 1 including an optical receiver 5 according to an embodiment. The optical transceiver module 1 is, for example, a 100G communication module using intensity modulation (NRZ: Non-Return-to-Zero) but is not limited to this example and may also be a 400G communication module using 4-level pulse amplitude modulation (PAM4).

[0013] The optical receiver 5 includes a receiver optical subassembly (ROSA) 10 as an optical receiving front-end circuit, and a slicer / clock data recovery (CDR) circuit 15, which is an electronic circuit. The optical receiver 5 also includes a processor 30, a memory 40, and a control and monitoring circuit 50. The processor 30, the memory 40, and the control and monitoring circuit 50 may be shared among components on the transmitting side of the optical transceiver module 1.

[0014] ROSA 10 includes an SOA 11, an optical demultiplexer 12, photodetectors 13a-13d provided for each demultiplexed channel, and preamplifiers 14a-14d, and converts the received optical signal of each channel into an electrical signal. Photodetectors 13a-13d are, for example, PIN-type photodiodes (denoted as "PIN-PD" in the figure). The photocurrent of each channel detected by photodetectors 13a-13d is amplified by the corresponding preamplifiers 14a-14d and output from ROSA 10 as an analog voltage signal.

[0015] In the configuration example shown in Figure 2, the ROSA 10 is a small optical component that does not have a monitoring mechanism before the SOA 11. As will be described later with reference to Figure 3, the processor 30 repeatedly estimates the input optical power for each channel and the total input optical power using a temporary value of the total input optical power of the WDM signals incident on the SOA 11, and converges the estimated values. Information regarding the converged input optical power for each channel may be notified to a transmission device to which the optical transceiver module 1 is connected as a type of module control / monitoring signal, or may be used for internal control of the optical receiver 5 via the control / monitoring circuit 50.

[0016] The analog voltage signal output from the ROSA 10 is discriminated and reproduced as a digital data string by the slicer / CDR circuit 15, and a clock is reproduced from the digital data string. The digital data string is output from the optical receiver 5 as a high-speed electrical main signal.

[0017] On the transmitting side of the optical transceiver module 1, the transmission signal for each channel is input as an electrical input to a slicer / CDR circuit 25. The output of the slicer / CDR circuit 25 is input to a laser diode driver (LDD) 24. The LDD 24 converts the input digital electrical signal into a drive signal for optical modulation.

[0018] The drive signal output from the LDD 24 is input to a Transmitter Optical Subassembly (TOSA) 20, which is an optical transmission front-end circuit. The TOSA 20 has LDs 24a to 24d as light sources. The light emitted from the LDs 24a to 24d is directly modulated by the corresponding drive signal. The modulated optical signals of each channel are multiplexed by an optical multiplexer (denoted as "O-Mux" in the figure) 21 and transmitted from the optical transceiver module 1 as a WDM signal.

[0019] 2 shows an optical transceiver module 1 for 4-channel WDM communication, but the number of channels is not limited to 4. WDM communication modules can be configured with any number of channels, such as 8 channels or 16 channels, as required.

[0020] 3 is a schematic diagram of the optical receiver 5. An optical signal input to the optical receiver 5 is amplified by the SOA 11. The SOA 11 is driven by a current supplied from a current source 16. A drive current I SOA is notified to the processor 30. Meanwhile, the signal light of each wavelength (channel) amplified by the SOA 11 and demultiplexed by the optical demultiplexer 12 is detected by the PIN-PD 13 and converted into a voltage signal by the corresponding preamplifier 14. The voltage signal for each channel is regenerated into a digital data stream by the slicer / CDR 15 and output as a high-speed electrical signal.

[0021] A part of the photocurrent detected by each PIN-PD 13 is monitored by a monitor circuit 51. The monitoring result by the monitor circuit 51 is input to the processor 30 as the PD input light intensity for each channel.

[0022] The processor 30 has the functions of a first calculator 31 that calculates the SOA gain for each channel, a second calculator 32 that calculates the input optical intensity to the SOA 11 for each channel, a third calculator 33 that calculates the total SOA input optical intensity, and a determination unit 34.

[0023] The first calculator 31 calculates the SOA drive current I SOAThe gain table 41 is stored in the memory 40 and describes the gain characteristics of each channel. In order to calculate the SOA gain of each channel, the SOA drive current I SOA In addition, the total input power of the WDM signal input to the SOA 11 is required.

[0024] In the optical receiver 5, a monitoring mechanism before the SOA 11 is omitted, so a tentative value is used as the initial value of the total input optical power of the WDM signal incident on the SOA 11. Even if a monitoring mechanism for some purpose is provided before the SOA 11, the input optical power for each channel can be determined using the tentative value of the total SOA input optical power without using the monitor value of the before-SOA. The tentative value of the total SOA input optical power can be an appropriately selected value, a design value of the transmission system, a value determined by calculation, etc. The first calculator 31 calculates the SOA drive current I SOA Based on the tentative total SOA input optical intensity, the SOA gain for each channel is calculated by referring to the gain table 41. The gain table 41 will be described in detail later.

[0025] The second calculator 32 calculates the input optical intensity for each channel of the WDM signal input to the SOA 11 based on the PD input optical intensity for each channel input from the monitor circuit 51 and the SOA gain for each channel input from the first calculator 31.

[0026] The third calculator 33 calculates the total SOA input optical power based on the input optical power for each channel calculated by the second calculator. This calculated value of the total SOA input optical power is fed back to the first calculator 31 and used to recalculate the SOA gain for each channel. The calculations by the first calculator 31, the second calculator 32, and the third calculator 33 are repeated until the total SOA input optical power converges. After each calculation, the calculated value (estimated value) of the total SOA input optical power is updated by the determination unit 34.

[0027] The third calculator 33 checks the convergence state of the total SOA input optical power, and when the estimated value of the total SOA input optical power has converged, outputs a convergence signal to the determination unit 34. Upon receiving the convergence signal from the third calculator 33, the determination unit 34 determines the estimated value of the input optical power for each channel at that time and outputs the determined input optical power for each channel. The input optical power for each channel is notified as a module control / monitoring signal to the transmission device to which the optical transceiver module 1 is connected, or is used for internal control of the optical receiver 5 via the control / monitoring circuit 50.

[0028] 4 is a flowchart showing the processing of the processor 30. The processor 30 acquires PD input optical intensity information for each channel, PDin_ch1, PDin_ch2, ..., PDin_ch n, from the monitor circuit 51 (S11). The PD input optical intensity information indicates the power of each signal light incident on the PIN-PDs 13a to 13d subsequent to the optical demultiplexer 12.

[0029] The processor 30 determines the SOA drive current value I set in the current source 16. SOA (S12). The processor 30 sets an estimated value Pin_total of the total SOA input optical power of the WDM signals incident on the SOA 11 to an initial value Pin_total_init (S13). Steps S11 to S13 may be performed in any order and may be performed simultaneously.

[0030] Next, the SOA drive current value I SOA Based on the temporarily set total SOA input optical power Pin_total (initial time: Pin_total_init), the SOA gain for each channel is obtained from the gain table 41 (S14). The SOA gain for each channel is multiplied by the PD input optical power for each channel obtained from the monitor circuit 51 to calculate the SOA input optical power Pin_ch1, Pin_ch2, ..., Pin_ch n for each channel (S15). The intensity of the signal light of each wavelength input to the SOA 11 is expressed as the product of the monitor optical power detected by each of the PIN-PDs 13a to 13d and the SOA gain of that channel.

[0031] Next, the sum of the SOA input optical intensities for each channel is calculated to calculate a new total SOA input optical intensity Pin_total_new (S16). If the error between the current Pin_total_new and the previous Pin_total is outside the allowable range (Yes in S17), the estimated value of the total SOA input optical intensity is updated (S18). After that, the process returns to step S14, and steps S14 to S18 are repeated. Steps S14 to S18 are repeated until the error between the current Pin_total_new and the previous Pin_total falls within the allowable range (No in S17). This repetition is referred to as iterative estimation process A.

[0032] When the error between the current Pin_total_new and the previous Pin_total falls within the allowable range, the calculated values of the SOA input optical power for each channel Pin_ch1, Pin_ch2, ..., Pin_ch n are output (S19). As will be described later, the convergence of the estimated value of the total SOA input optical power by the iterative estimation process A is extremely fast, and the SOA input optical power for each channel can be estimated quickly and accurately without using a monitor mechanism in front of the SOA 11.

[0033] 4 is repeatedly performed by the processor 30 during actual service. The intensity of the WDM signal received by the optical receiver 5 can change due to aging degradation of the transmitting communication device and fluctuations in the optical transmission path. Even without using a monitor mechanism in the upstream stage of the SOA 11, the input optical intensity of each channel of the WDm signal input to the SOA 11 can be accurately determined, maintaining the reliability of the control and monitoring of the optical receiver 5.

[0034] 5 is a diagram showing an example of the gain table 41 stored in the memory 40. Here, a four-channel WDM signal is taken as an example, and gain tables 41-1 to 41-4 for channels Ch1 to Ch4 are used.

[0035] For each channel, the SOA drive current I SOA The SOA gain (dB) is specified by the drive current I (mA) and the total SOA input optical power (dBm) of the WDM signals incident on the SOA 11. SOAThe SOA gain for each channel, which is determined by the power dissipation (mA) and the total input optical power Pin_total (dBm) of the WDM signals incident on the SOA 11, is measured and recorded in advance.

[0036] FIG. 6 shows the information described in the gain table 41-1 of one channel, for example, channel Ch1, in FIG. 5 as a characteristic diagram 41-1a. The horizontal axis represents the total SOA input optical power Pin_total, and the vertical axis represents the SOA gain. The SOA drive current I SOA The SOA gain is shown as a function of the total SOA input optical power for eight values of I in the range from 20 mA to 180 mA.

[0037] The first calculator 31 of the processor 30 calculates the SOA drive current I set in the current source 16. SOA and the total SOA input optical power (a tentative initial value or an estimated value during iterative calculation), the second calculator 32 refers to gain tables 41-1 to 41-4 for each channel to identify the SOA gain for each channel. The second calculator 32 calculates the SOA input optical power for each channel based on the SOA gain for each channel and the monitoring results of PIN-PDs 13a to 13d. The third calculator 33 calculates a new total SOA input optical power Pin_total_new from the sum of the SOA input optical power for each channel.

[0038] This calculation performed by the processor 30 is expressed by the following formula:

[0039]

number

[0040] Here, Pin_ch n is the SOA input optical power for each channel. Multiplying this SOA input optical power for each channel by the SOA gain of that channel and the loss LOSSn due to the optical demultiplexer 12 gives the PD input optical power incident on the corresponding PIN-PDn. Therefore, Pin_ch n is expressed as the value obtained by dividing the input optical power PIN_PD_in n to the PD by the loss LOSSn due to the optical demultiplexer 12 and the SOA gain Gn for each channel. The SOA gain Gn for each channel is calculated by multiplying the SOA drive current I SOA The new total SOA input optical power Pin_total_new is obtained from the gain tables 41-1 to 41-4 using the provisional total SOA input optical power Pin_ch-n. The new total SOA input optical power Pin_total_new is calculated as the sum of the SOA input optical power Pin_ch-n of each channel.

[0041] Using this simple calculation formula, the total SOA input optical power is repeatedly calculated until the total SOA input optical power Pin_total_new converges.

[0042] Figure 7 shows the experimental results of the convergence of the detection error of the input optical power due to repeated calculations for a certain channel. The error before the calculation starts is varied in a range of ±20 dB, and the convergence status is calculated. As shown in area B, the error converges to less than 0.5 dB after repeating the calculation four or more times. When the initial setting value (provisional value) of the total SOA input optical power is within an error of ±3 dB from the actual value, the error converges to less than 0.5 dB after just three repetitions.

[0043] The results in Figure 7 show that even if the initially selected tentative total SOA input optical power value is significantly different from the actual value, repeating the calculation four or more times will converge to a more accurate total SOA input optical power value. Depending on the design, the number of calculation iterations may be limited to a certain number, for example, three. In this case, it is desirable to select an initial value with a smaller error.

[0044] Figure 8 shows an example of calculating the initial value of the tentative total SOA input power. The initial value of the total SOA input power is calculated by the SOA drive current I SOAThe value can be narrowed down to a value that is somewhat close based on the gain table 41 and the information on the PD input optical intensity for each of the PIN-PDs 13a to 13d. For example, by using an intermediate value between the maximum and minimum possible errors or an average value, the actual total SOA input optical intensity can be approximated to some extent.

[0045] First, for the optical power PDin_ch-n of each wavelength that is amplified by the SOA 11, demultiplexed, and input to the PIN-PD 13n of each channel, the minimum value Pin_ch n_min that can be taken by the SOA input optical power Pin_ch n is calculated (S131). Also, for the optical power PDin_ch n of each wavelength that is input to the PIN-PD 13n of each channel, the maximum value Pin_ch n_max that can be taken by the SOA input optical power Pin_ch n is calculated (S132). Steps S131 and S132 may be performed in any order, or simultaneously.

[0046] The average of the sum of the minimum values Pin_ch n_min and the sum of the maximum values Pin_ch n_max of all channels is determined as the initial value of the total SOA input optical intensity (S133).

[0047] Figure 9 shows an example of calculating the initial value for estimating the total SOA input optical power. The horizontal axis represents the input optical power Pin_ch to the SOA for each channel, and the vertical axis represents the input optical power (PD_in n) to the PIN-PD 13n for each channel.

[0048] The solid line (1) shows the characteristics when all channels have the same optical intensity. The dashed line (2) shows the characteristics when the total SOA input optical intensity is the same as (1), but the optical intensity of a certain channel Pin_ch n incident on the SOA 11 is minimum. The dashed line (3) shows the characteristics when the total SOA input optical intensity is the same as (1), but the optical intensity of a certain channel incident on the SOA 11 is maximum. The three characteristics of lines (1) to (3) are measured in advance and stored in memory 40.

[0049] The intersection of the horizontal dotted line and line (1) when PD_in n is X(dMm) indicates the SOA input optical power for each channel when all channels have the same input optical power. The intersection of the horizontal dotted line and line (2) when PD_in n is X(dMm) indicates the minimum possible value for the SOA input optical power Pin_ch n for each channel when PD_in n is X(dMm). The intersection of the horizontal dotted line and line (3) when PD_in n is X(dMm) indicates the maximum possible value for the SOA input optical power Pin_ch n for each channel when PD_in n is X(dMm).

[0050] The minimum value Pin_ch n_min of the SOA input light intensity for each channel can be calculated, for example, by the following equation.

[0051]

number

[0052] The optical input power to the PIN-PD 13n for each channel is calculated by multiplying the minimum SOA input power for each channel, Pin_ch n_min, by the SOA gain Gn for that channel. That is, line (2) in Figure 9 shows the characteristics of the SOA gain Gn for which Pin_ch n is minimum.

[0053] The minimum value of the SOA input optical power for each channel, Pin_ch n_min, is the total SOA input optical power for all channels, Pin_total, divided by div1. In the case of four channels, div1 is 4×∂p, or 4×10 Δp / 10 Δp is the difference between line (1) and line (2) when PD_in n is X (dBm) in Figure 9. Here, only Δp is expressed in units of [dB] (logarithm), and the rest are expressed in antilogarithm.

[0054] The maximum value Pin_ch n_max of the SOA input light intensity for each channel can be calculated, for example, by the following formula.

[0055]

number

[0056] The input optical power to the PIN-PD 13n for each channel is the maximum SOA input optical power for each channel, Pin_ch n_max, multiplied by the SOA gain Gn for that channel. That is, line (3) in Figure 9 shows the characteristics of the SOA gain Gn when Pin_ch n is at its maximum.

[0057] The maximum value of the SOA input optical power for each channel, Pin_ch n_max, is the value obtained by dividing the total SOA input optical power for all channels, Pin_total, by div2. In the case of four channels, div1 is 4 × ∂m, or 4 × 10 Δm / 10 Δm is the difference between line (1) and line (3) when PD_in n is X (dBm) in Figure 9. Here, only Δm is expressed in units of [dB] (logarithm), and the rest are expressed in antilogarithm.

[0058] 9, i.e., by storing the three gain tables in memory 40 and searching for a point that satisfies the Pin_ch n_min calculation formula, the minimum value Pin_ch n_min of the SOA input optical intensity for each channel can be easily found. Also, by searching the three gain tables for a point that satisfies the Pin_ch n_max calculation formula, the maximum value Pin_ch n_max of the SOA input optical intensity for each channel can be easily found.

[0059] The initial value Pin_total_init of the total SOA input light intensity can be calculated by the following formula.

[0060]

number

[0061] This formula means that the logarithmic average of the sum of Pin_ch n_min and the sum of Pin_ch n_max is taken, and then converted to an anti-logarithm. If the logarithmic average of the sum of Pin_ch n_min and the sum of Pin_ch n_max is taken, the result may be biased towards Pin_ch n_max.

[0062] By storing the three types of characteristics (gain tables) in Figure 9 in memory 40, when the number of iterations of the iterative calculation is limited, the initial value of the total SOA input optical intensity can be easily calculated and used as a provisional value at the start of the iterative calculation.

[0063] The above process allows accurate estimation of the SOA input optical intensity for each channel through iterative calculations without directly measuring the input optical intensity to the SOA 11. In this case, the number of optical components in the optical receiver 5 can be reduced, further miniaturizing the module, and the optical input dynamic range can be expanded.

[0064] Although the present invention has been described above based on specific configuration examples, the present invention is not limited to the above examples. When there is a limit to the number of iterations of the iterative calculation, the calculation of the temporary initial value may involve averaging Pin_ch n_min and Pin_ch n_max for each channel, instead of averaging the sum of Pin_ch n_min and the sum of Pin_ch n_max, and then calculating the average or median value for all channels. When there is no limit to the number of iterations, a randomly selected appropriate value may be used as the initial value of the total SOA input optical intensity. [Explanation of symbols]

[0065] 1 Optical transceiver module 5 Optical receiver 10 ROSA 11 SOA (Optical Amplifier) 12 Optical demultiplexer 13a to 13d, 13n PIN-PD (photodetector) 14a~14d Preamp 15, 25 Slicer / CDR 20 TOSA 21 Optical multiplexer 23a~23d LD (light source) 24 LDD 30 processors 40 memory 41, 41-1 to 41-4 Gain Table 50 Control and monitoring circuit

Claims

1. an optical amplifier that amplifies an optical signal in which a plurality of wavelengths are multiplexed; a current source for driving the optical amplifier; an optical demultiplexer that demultiplexes the optical signal amplified by the optical amplifier into individual wavelengths; a photodetector for detecting light of each of the demultiplexed wavelengths; a monitor circuit for monitoring the light intensity of each wavelength detected by the photodetector; a processor; Memory and and the memory holds information representing a relationship between a total input optical intensity of the optical signals input to the optical amplifier and a gain of the optical amplifier for each wavelength; the processor repeats the following calculations until the total input optical intensity converges: a first calculation for specifying a gain for each wavelength by referring to the information stored in the memory based on the drive current value of the current source and the estimated value of the total input optical intensity; a second calculation for calculating an input optical intensity for each wavelength input to the optical amplifier based on the specified gain for each wavelength and the monitor value of the optical intensity for each wavelength acquired by the monitor circuit; and a third calculation for calculating the total input optical intensity from the sum of the input optical intensities for each wavelength. Optical receiver.

2. the processor uses a temporary value of the total input light intensity at the start of each iteration of the first calculation, the second calculation, and the third calculation; 2. The optical receiver of claim 1.

3. the processor calculates an initial estimate of the total input optical intensity based on the drive current value, the information stored in the memory, and the monitor value acquired by the monitor circuit at the start of the iterative processing of the first calculation, the second calculation, and the third calculation.

2. The optical receiver of claim 1.

4. the processor calculates, as the initial estimate, an average or median of maximum and minimum values that the input optical intensity of each wavelength input to the optical amplifier can take; 4. The optical receiver according to claim 3.

5. the processor outputs the input optical power of each wavelength of the optical signal input to the optical amplifier when the total input optical power has converged.

5. An optical receiver according to claim 1.

6. a control and monitoring circuit that uses the input optical intensity of each wavelength of the optical signal input to the optical amplifier for internal control of the optical receiver; Further having 6. The optical receiver according to claim 5.

7. An optical receiver according to any one of claims 1 to 6; an optical transmission circuit that converts an electrical signal into an optical signal; and an optical transceiver module having the same.

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