Optical module optical signal loss processing circuit and method

Abstract

The application provides an optical module optical signal loss processing circuit and method, and belongs to the technical field of optical signal processing. The circuit comprises a conversion module, which is used for converting a current output by a photodetector into a voltage, and superimposing a preset bias voltage on the converted voltage to obtain a current voltage; a detection module, which is used for comparing the current voltage with a signal loss dynamic threshold value, and outputting a signal loss indication signal if the current voltage is lower than the signal loss dynamic threshold value; and a control module, which is used for outputting an interruption indication signal according to a received signal loss indication signal. The application has the advantages of rapid response capability at the hardware level, and the temperature compensation of the dynamic threshold value ensures the detection accuracy at different temperatures.

Description

Technical Field

[0001] This application relates to the field of optical signal processing technology, and in particular to a circuit and method for handling optical signal loss in an optical module. Background Technology

[0002] In fiber optic communication systems, when a signal in a fiber optic link cannot be transmitted normally due to some reason (such as fiber breakage, loose connector, equipment failure, etc.), the system needs to detect the LOS (Loss of Signal) and take timely measures, such as switching to a backup link, to ensure the continuity and reliability of communication.

[0003] Traditional signal loss handling primarily relies on software, but software response times are relatively long, typically ranging from tens to hundreds of milliseconds. In some applications with extremely stringent latency requirements, this response time is insufficient. Summary of the Invention

[0004] This application provides a circuit and method for optical module optical signal loss processing to solve the problem of slow response speed in signal loss processing.

[0005] In a first aspect, this application provides an optical module optical signal loss processing circuit, the circuit comprising:

[0006] The conversion module is used to convert the current output by the photodetector into voltage, and then add a preset bias voltage to the converted voltage to obtain the current voltage;

[0007] The detection module is used to compare the current voltage with the signal loss dynamic threshold. If the current voltage is lower than the signal loss dynamic threshold, a signal loss indication signal is output.

[0008] The control module is used to output an interruption indication signal based on the received signal loss indication signal.

[0009] Secondly, this application also provides a method for processing optical signal loss in an optical module, the method comprising:

[0010] The current output by the photodetector is converted into voltage, and a preset bias voltage is added to the converted voltage to obtain the current voltage;

[0011] The current voltage is compared with the signal loss dynamic threshold. If the current voltage is lower than the signal loss dynamic threshold, a signal loss indication signal is output.

[0012] When the received signal loss indication signal is received, an interrupt indication signal is output.

[0013] This application provides an optical module signal loss processing circuit and method. The circuit's conversion module converts the current output by the photodetector into voltage, and a preset bias voltage is superimposed to obtain the current voltage. The detection module can compare the current voltage with a signal loss dynamic threshold in real time. When the current voltage is detected to be lower than the signal loss dynamic threshold, the detection module immediately outputs a signal loss indication signal. This hardware-level detection module has a high response speed because it does not rely on software processing but directly compares and responds at the hardware level. Once the control module detects the signal loss indication signal, it immediately stops its current task, and the interrupt controller executes an interrupt handler to ensure a rapid response when signal loss is detected, without delay due to the execution of other tasks. Furthermore, the signal loss dynamic threshold is a temperature-related dynamic value, determined by the control module based on calibration values. The setting of the signal loss dynamic threshold ensures accurate detection of signal loss even under different temperature conditions.

[0014] Therefore, the advantage of this application lies in its fast response capability at the hardware level, such as the ability to detect and respond to signal loss immediately within microseconds, while the temperature compensation of the dynamic threshold ensures the detection accuracy at different temperatures. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the optical module optical signal loss processing circuit provided in the embodiments of this application;

[0017] Figure 2 This is a flowchart of the optical module optical signal loss processing method provided in the embodiments of this application;

[0018] Figure 3 A flowchart of a signal loss threshold debugging method provided in one embodiment;

[0019] Figure 4 This is a flowchart illustrating the calibration signal loss baseline threshold provided in an embodiment of this application;

[0020] Figure 5 This is a flowchart of the model for the relationship between calibrated dark current and temperature provided in the embodiments of this application;

[0021] Figure 6This is a flowchart of the calculation of the dynamic threshold for signal loss provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0024] This application provides a circuit and method for handling optical signal loss in an optical module. In the optical module, the optical signal received by the photodetector is converted into a current signal. Then, the conversion module of the optical signal loss handling circuit converts this current signal into a voltage signal, and a preset bias voltage is superimposed to obtain a voltage value representing the current optical signal strength. To achieve a fast response, the circuit also includes a hardware-level detection module that can compare the current voltage value with a dynamic signal loss threshold in real time. This dynamic signal loss threshold is adjusted according to temperature changes to ensure accurate detection of signal loss under different temperature conditions. When the detection module detects that the current voltage is lower than the dynamic signal loss threshold, it immediately issues a signal loss indication signal. Because this detection process is performed at the hardware level, it does not rely on software processing and therefore has a high response speed. Once the control module receives the signal loss indication signal, it immediately interrupts the currently executing task and executes a dedicated interrupt handler. This allows for a rapid response to signal loss events without delays caused by software task execution.

[0025] The following is combined with Figures 1-6 This application describes the optical module optical signal loss processing circuit and method.

[0026] Please refer to Figure 1 , Figure 1 This is a schematic diagram of an optical module optical signal loss processing circuit provided in an embodiment of this application. An optical module optical signal loss processing circuit includes a conversion module 10, a detection module 20, and a control module 30.

[0027] For example, the conversion module 10 is used to convert the current output by the photodetector into voltage, and to superimpose a preset bias voltage on the converted voltage to obtain the current voltage.

[0028] Specifically, after receiving a light signal, the photodetector generates a current proportional to the light intensity. This current signal is generally very weak and needs to be amplified and converted by a conversion module so that subsequent circuitry can process it. The conversion module converts the current signal into a voltage signal. A preset bias voltage is applied to ensure that the converted voltage signal is within a suitable voltage range, allowing the detection module to detect and process it. Setting the bias voltage helps adjust the dynamic range of the signal, ensuring that the voltage signal remains within a detectable range under different light intensity conditions.

[0029] For example, the detection module 20 is used to compare the current voltage with the signal loss dynamic threshold. If the current voltage is lower than the signal loss dynamic threshold, a signal loss indication signal is output.

[0030] Specifically, the detection module 20 continuously compares the current voltage value output by the conversion module 10 with the signal loss dynamic threshold. If the detected current voltage value is lower than this dynamic threshold, the detection module 20 immediately outputs a signal loss indication signal. This signal loss indication signal can trigger the control module to start an interrupt program. Therefore, the main function of the detection module 20 is to provide a fast and automated mechanism to detect optical signal loss and respond promptly to the output signal loss indication signal, ensuring the stability and reliability of the optical communication system. By using a temperature-related dynamic threshold, the detection module 20 can maintain detection accuracy under different environmental conditions, which is crucial for the performance of the optical communication system.

[0031] For example, the control module 30 is configured to output an interruption indication signal when the received signal loss indication signal is received.

[0032] Specifically, when the control module 30 receives a signal loss indication signal from the detection module 20, it immediately outputs an interrupt indication signal. This interrupt indication signal can be used to interrupt the currently executing task and trigger the execution of a specific interrupt handler to deal with the signal loss situation.

[0033] In addition, the control module 30 is also used to evaluate the input optical power based on the sampled current voltage value and report the evaluation results.

[0034] Specifically, the control module 30 assesses the optical power level input to the system based on the current voltage value output by the conversion module 10. This assessment process converts the voltage value into an estimated optical power value. The assessment result is reported to the system, for example, by transmitting it to a monitoring system via a network interface.

[0035] In some embodiments, the signal loss dynamic threshold is a dynamic value, which is obtained by the control module based on calibration and combined with the current temperature; the signal loss dynamic threshold includes the calibrated basic signal loss threshold and the fitted dark current value at the current temperature. The signal loss dynamic threshold is obtained by adding the basic signal loss threshold and the fitted dark current value at the current temperature.

[0036] Specifically, the dynamic threshold for signal loss consists of two parts: a calibrated baseline threshold for signal loss and a fitted dark current value at the current temperature. It is used to determine whether a signal has been lost in an optical communication system. The calibrated baseline threshold for signal loss is a fixed threshold determined beforehand through a calibration process. It represents the lowest voltage level at which the system considers the signal to be lost, assuming no temperature influence. This dynamic threshold for signal loss can be determined during the system design or testing phase, based on the system's performance requirements and the expected signal strength range. Dark current refers to a tiny current generated by the photodetector even in the absence of light. This current varies with temperature. Therefore, a dark current value needs to be fitted based on the current temperature. This value reflects the effect of temperature on the photodetector output.

[0037] In short, the signal loss dynamic threshold is a temperature-dependent threshold used to determine whether an optical signal has been lost. It takes into account the effect of temperature on the output of the photodetector to improve the accuracy and reliability of signal loss detection.

[0038] The following describes the conversion module 10, the detection module 20, and the control module 30.

[0039] In some embodiments, such as Figure 2 As shown, the detection module 20 includes a comparator (CMP) 201.

[0040] To improve the accuracy of optical signal loss detection, the comparator 201 needs to be biased. Comparator 201 may have an offset voltage, especially in low-cost comparators or those integrated into an MCU. This offset voltage can reach ±10mV to ±20mV. At lower optical signal strengths, such as -16dBm, the corresponding voltage is approximately 15-20mV. If the offset voltage of comparator 201 is negative, for example -20mV, and the minimum supply voltage is 0V, comparator 201 will not be able to output a negative voltage. This will prevent the flipping at the signal loss dynamic threshold, thus affecting detection accuracy. Therefore, this application improves upon this by applying a preset bias voltage (e.g., approximately +15mV) to the first resistor R1 to compensate for the negative offset voltage of comparator 201, ensuring that comparator 201 can correctly flip when the optical signal strength decreases to the signal loss dynamic threshold, thereby improving the accuracy of signal loss detection.

[0041] For example, the conversion module 10 includes a transimpedance amplifier (TIA) 101, a first resistor R1, and a second resistor R2. The input of the transimpedance amplifier 101 is connected to the output of the photodetector. The transimpedance amplifier 101 includes an RSSI (Received Signal Strength Indication) pin, which is used to mirror the current of the photodetector. That is, regardless of the current flowing through the photodetector, the RSSI pin will replicate this current at a certain ratio. This ratio can be 1:1 (i.e., the current output by the RSSI pin is the same as the current in the photodetector) or 4:1 (i.e., the current output by the RSSI pin is one-quarter of the current in the photodetector). One end of the series connection between the first resistor R1 and the second resistor R2 is connected to a first power supply, and the other end is grounded. The connection node between the first resistor R1 and the second resistor R2 is connected to the output of the transimpedance amplifier 101, so that the voltage output by the transimpedance amplifier 101 is superimposed with the bias voltage provided by the first power supply to obtain the current voltage. The transimpedance amplifier 101 is used to convert the current output by the photodetector into a voltage.

[0042] Specifically, the first resistor R1 is a pull-up resistor connected to the first power supply to provide a preset bias voltage. The first resistor R1 works in conjunction with the second resistor R2 to form a preset bias voltage through the first power supply (e.g., the MCU's reference voltage can be selected as the first power supply). The purpose of setting this bias voltage is to compensate for the offset voltage of comparator 201, ensuring that comparator 201 can flip at the correct threshold point, thereby improving the accuracy of optical signal loss detection. The second resistor R2 is a sampling resistor. When the current output from the photodetector flows through the second resistor R2, a voltage drop proportional to the current is generated across it. The value of the second resistor R2 needs to be selected to ensure that, under the expected optical signal intensity, the generated voltage drop accurately reflects the signal strength, and, after adding the bias voltage provided by the first resistor R1, can be effectively compared with the signal loss dynamic threshold input to comparator 201.

[0043] In some embodiments, the conversion module 10 includes a first node ①, a second node ②, and a third node ③. The conversion module 10 also includes a first capacitor C1, which has a first terminal and a second terminal. The first terminal of the first capacitor C1 is connected to the first node ①. The connection node between the first resistor R1 and the second resistor R2 serves as the second node ②, connected to the first node ①. The third node ③ is connected to the third resistor R3 of the detection module 20 and the analog-to-digital converter (ADC) of the control module 30, respectively.

[0044] Specifically, the first capacitor C1 is a decoupling capacitor connected to the RSSI pin of the transimpedance amplifier 101. The function of the first capacitor C1 is to ensure the stability of the sampling voltage of the RSSI pin, preventing any power supply noise or voltage fluctuations from affecting the RSSI pin reading, thereby ensuring the accuracy of signal strength measurement.

[0045] In some embodiments, the detection module 20 includes a fourth node ④, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The comparator 201 has a positive input (+), a negative input (-), and an output. The third resistor R3 has a first terminal and a second terminal; the first terminal of the third resistor R3 is connected to the third node ③, and the second terminal of the third resistor R3 is connected to the negative input (-) of the comparator 201. The fourth resistor R4 has a first terminal and a second terminal; the first terminal of the fourth resistor R4 is connected to the output of the digital-to-analog converter (DAC), which outputs a signal loss dynamic threshold; the second terminal of the fourth resistor R4 is connected to the positive input (+) of the comparator 201 via the fourth node ④. The fifth resistor R5 has a first terminal and a second terminal; the first terminal of the fifth resistor R5 is connected to the fourth node ④, and the second terminal of the fifth resistor R5 is connected to the output of the comparator 201.

[0046] For example, comparator 201 also has a positive power supply terminal and a negative power supply terminal. The positive power supply terminal of comparator 201 is connected to a second power supply, and the negative power supply terminal is grounded. The positive power supply terminal is connected to the positive power supply voltage VCC, providing a positive operating voltage for the internal circuitry of the comparator. This voltage determines the maximum value of the comparator's output high level. For example, if the positive power supply voltage is 3.3V, then the high level of the comparator's output will be close to 3.3V. The negative power supply terminal is connected to the circuit's ground (GND) or negative power supply voltage (VEE). For example, in a single-supply system, the negative power supply terminal is directly connected to ground, while in a dual-supply system, it is connected to a negative voltage value, such as -5V. The negative power supply terminal provides a reference ground potential for the internal circuitry of comparator 201, ensuring that comparator 201 can correctly compare input signals and output the correct logic level.

[0047] Specifically, the third resistor R3 transmits the voltage signal output from the transimpedance amplifier 101 to the inverting input terminal (-) of the comparator 201 via the conversion module 10. Thus, the third resistor R3 acts as a signal transmitter, sending the current voltage to the comparator 201 for comparison. The fourth resistor R4 transmits the signal loss dynamic threshold from the digital-to-analog converter (DAC) output to the positive input terminal (+) of the comparator 201. This signal loss dynamic threshold is provided to the comparator 201 to determine whether the current input voltage reaches the voltage level required for signal loss. In other words, the fourth resistor R4 ensures that the signal loss dynamic threshold can be input to the comparator 201. The fifth resistor R5 connects the positive input terminal (+) and the output terminal of the comparator 201, forming a positive feedback loop. Positive feedback introduces hysteresis, making the output of the comparator 201 more stable near the flip point and preventing frequent output flipping due to small fluctuations in the current input voltage.

[0048] Furthermore, the fourth resistor R4 and the fifth resistor R5 can be used to configure the hysteresis voltage threshold of comparator 201. The hysteresis voltage threshold is designed to ensure that comparator 201 can stably respond to changes in the current voltage when the current voltage approaches the signal loss dynamic threshold, avoiding frequent output switching due to small fluctuations in the input current voltage signal. The formula for calculating the hysteresis voltage threshold is:

[0049] Vthreshold=(VCC-VEE)*R4 / (R4+R5);

[0050] Where Vthreshold represents the hysteresis voltage threshold, VCC represents the positive supply voltage of the comparator, VEE represents the negative supply voltage of the comparator, R4 represents the value of the fourth resistor, and R5 represents the value of the fifth resistor. This formula shows that the hysteresis voltage threshold equals the difference between the positive and negative supply voltages of the comparator, multiplied by the proportion of resistance of the fourth resistor in the series circuit consisting of the fourth and fifth resistors. By adjusting the values ​​of the fourth resistor R4 and the fifth resistor R5, the hysteresis voltage threshold can be flexibly set to meet specific system requirements. For example, the hysteresis voltage threshold can be set to approximately 15.7mV.

[0051] For example, the detection module 20 further includes a second capacitor C2. The second capacitor C2 has a first terminal and a second terminal. The first terminal of the second capacitor C2 is connected to a second power supply, and the second terminal of the second capacitor C2 is grounded. The second capacitor C2 is a decoupling capacitor, which is placed on the power supply line of the comparator 201. Its function is to stabilize the power supply voltage of the comparator 201 and prevent noise or voltage fluctuations on the power supply line from affecting the performance of the comparator 201.

[0052] In some embodiments, the control module (i.e., the Microcontroller Unit) 30 includes an analog-to-digital converter (ADC) 301, a digital-to-analog converter (DAC) 302, and an interrupt controller 303. The ADC 301 of the control module 30 is connected to a third node ③ and is used to convert the sampled current voltage analog signal into a digital signal. The DAC 302 is used to output a signal loss dynamic threshold. The interrupt controller is connected to the output of the comparator 201; when the comparator 201 outputs a signal loss indication signal, the interrupt controller 303 outputs an interrupt indication signal.

[0053] Specifically, the output of comparator 201 can be connected to the interrupt pin of the MCU. Once comparator 201 toggles, it can quickly trigger an interrupt in the MCU, and the interrupt controller 303 will output an interrupt indication signal. For example, when the current voltage value of the negative input (-) of comparator 201 is less than the signal loss dynamic threshold, comparator 201 outputs a high-level signal (e.g., 3.3V) to indicate a signal loss indication signal; otherwise, it outputs a low-level signal (e.g., 0V).

[0054] In other embodiments, please refer to Figure 2 , Figure 2 This is a flowchart of an optical module optical signal loss processing method provided in an embodiment of this application. This application also provides an optical module optical signal loss processing method, including:

[0055] S210, the conversion module converts the current output by the photodetector into voltage, and then adds a preset bias voltage to the converted voltage to obtain the current voltage.

[0056] S220, the detection module receives the current voltage.

[0057] S230, the detection module compares the current voltage with the magnitude of the signal loss dynamic threshold.

[0058] Among them, the dynamic threshold for signal loss is a temperature-related dynamic value, which is obtained by the control module based on calibration.

[0059] If the current voltage is below the signal loss dynamic threshold, then execute S240.

[0060] If the current voltage is not lower than the signal loss dynamic threshold, then return to execute S220.

[0061] S240, the detection module output signal is lost, indicating the signal is missing.

[0062] S250, the control module evaluates the input optical power based on the sampled current voltage and reports the evaluation results.

[0063] S260, the control module receives the signal loss indication signal and outputs the interrupt indication signal.

[0064] The following describes the calibration process for the dynamic threshold of signal loss.

[0065] Please refer to Figure 3 , Figure 3 This is a flowchart illustrating a signal loss threshold debugging method provided in one embodiment. A signal loss threshold debugging method includes:

[0066] S310, Input optical power value.

[0067] First, the ATS (Automatic Test System) inputs a specific optical power value, which is the signal loss threshold that the optical module needs to detect and report.

[0068] S320, adjust the signal loss threshold.

[0069] Next, the ATS adjusts the signal loss threshold according to a preset fixed step size. This means that the ATS will change the signal loss threshold by a certain step increment or decrement in order to find a suitable value so that the optical module can report a signal loss indication signal when the input optical power is lower than this threshold.

[0070] S330, check if a signal loss indication signal has been reported.

[0071] Then, the ATS checks whether the optical module has reported a signal loss indication signal according to the adjusted signal loss threshold.

[0072] If the optical module reports a signal loss indication signal, it means that the current signal loss threshold setting is correct, and the ATS will execute S340.

[0073] If the optical module does not report a signal loss indication signal, it means that the current signal loss threshold setting is incorrect. The ATS will then return to S320 and continue to adjust the threshold in fixed steps.

[0074] S340, write signal loss threshold.

[0075] Once the optical module correctly reports the signal loss indication signal, the ATS writes the final determined signal loss threshold into the optical module, and the optical module will then use this threshold to detect signal loss.

[0076] The entire process from S310 to S340 is an iterative adjustment and verification process, the purpose of which is to find and set a suitable signal loss threshold so that the optical module can accurately detect signal loss. This process is led by ATS.

[0077] Figure 3 The signal loss threshold debugging method shown is performed by the ATS (Automatic Transmission System). During debugging, the system needs to add a waiting time after each I2C (Inter-Integrated Circuit) command sent by the ATS. During debugging, the signal loss threshold is gradually adjusted from low to high. After each adjustment, the ATS checks the optical module status to determine if the conditions for reporting signal loss have been met. This process needs to be repeated until the optical module successfully reports a signal loss indication signal. However, this iterative debugging process results in a significant amount of time being spent on waiting for delays and determining a suitable signal loss threshold.

[0078] Furthermore, the signal loss threshold established above was not temperature-compensated. Without temperature compensation for the signal loss threshold, the trigger point (i.e., the threshold) for signal loss detection may shift at different operating temperatures (e.g., low temperature, room temperature, and high temperature). This shift is called "drift." It means that the optical module's sensitivity to optical signal intensity differs at different temperatures, causing the signal loss threshold set at one temperature to be inapplicable at another.

[0079] To improve the efficiency of debugging the signal loss threshold and to perform temperature compensation for the signal loss threshold, this application also provides a method for calibrating the basic signal loss threshold. Please refer to [reference needed]. Figure 4 , Figure 4This is a flowchart illustrating the calibration signal loss baseline threshold provided in an embodiment of this application. The method includes:

[0080] S410, the control module receives the signal loss debugging command issued by the ATS to instruct the execution of signal loss debugging operation.

[0081] S420 uses the input optical power currently received by the analog-to-digital converter of the control module as the initial value of signal loss for the digital-to-analog converter, and adjusts the initial value of signal loss to obtain the target value of signal loss.

[0082] Specifically, in the optical module's signal loss processing circuit, the threshold of the digital-to-analog converter (DAC) is essentially equal to the current value of the analog-to-digital converter (ADC). As long as the DAC's setpoint is greater than the ADC's actual measured value, a signal loss indication signal can be triggered. Therefore, the current ADC value can be directly used as the initial signal loss value for the DAC. Based on this, a suitable target signal loss value can usually be found with only one or two fine-tuning adjustments. However, to prevent fluctuations in the ADC's measured value from affecting the accuracy of the threshold, a value slightly higher than the current ADC value can be selected as the initial signal loss value for the DAC. This allows for faster setting of the target signal loss value, thus simplifying the debugging process.

[0083] The analog-to-digital converter (ADC) can receive and convert the current input optical power into a digital signal in real time. This digital signal is used as the initial value for signal loss in the ADC. Since the input optical power changes dynamically, the initial value for signal loss can also be adjusted accordingly. This dynamic adjustment capability allows the signal loss detection point to be flexibly set according to the actual optical power level.

[0084] S430: The dark current value fitted at the current temperature is calculated using a pre-calibrated model of the relationship between dark current and temperature. The dark current value is then subtracted from the target value of signal loss to obtain the basic threshold for signal loss.

[0085] Specifically, once the target value for signal loss is determined, it needs to be corrected. The purpose of this correction is to eliminate the influence of dark current on signal loss detection, ensuring the accuracy of the baseline signal loss threshold. Specifically, the target value for signal loss is subtracted from the fitted dark current value at the current temperature. The result is a "pure" baseline signal loss threshold that does not contain the influence of dark current. This pure baseline threshold reflects the condition that the signal loss indication signal will only be triggered when the light signal intensity falls below a certain level. Finally, this corrected baseline signal loss threshold is written into the register of the control module.

[0086] In this way, during normal operation of the optical module, the MCU reads the basic signal loss threshold from the register and adds it to the dark current value fitted at the current temperature to obtain a dynamic signal loss threshold. This dynamic signal loss threshold is adjusted in real time according to the magnitude of the dark current; the larger the dark current, the larger the dynamic signal loss threshold. This dynamic compensation mechanism ensures that the signal loss detection point remains stable under different temperature conditions, thereby improving the performance and reliability of the optical module in various environments.

[0087] In S410 to S430 above, S410 initiates the signal loss debugging process via ATS, ensuring the control module begins executing relevant debugging operations. S420 determines an initial signal loss value during the debugging process and further optimizes it to obtain the final target signal loss value. S430 calibrates the target signal loss value to eliminate the influence of dark current on signal loss detection in the optical module, thereby obtaining a "pure" basic signal loss threshold that does not contain the influence of dark current.

[0088] For example, S420 specifically includes:

[0089] S421, determine whether the detection module outputs a signal loss indication signal because the reported input optical power is lower than the initial value of signal loss.

[0090] If the detection module does not output a signal and the indication signal is lost, then execute S422;

[0091] If the detection module outputs a signal loss indication signal, then execute S423.

[0092] S422, gradually increase the initial value of signal loss to obtain the corresponding current value of signal loss.

[0093] S423, take the current value of signal loss as the target value of signal loss, which includes the fitted dark current value at the current temperature.

[0094] In S421 to S423 above, S421 checks whether the detection module has reported a signal loss indication signal because the input optical power is lower than the set initial signal loss value. If the detection module does not output a signal loss indication signal, it means that the current initial value is set too high; if the detection module has already output a signal loss indication signal, it means that the initial value is set too low or appropriate. S422 finds a suitable signal loss trigger point by increasing the threshold. S423 ensures that the obtained signal loss target value is based on the actual optical power detection and also considers the effect of temperature on dark current.

[0095] Please refer to Figure 5 , Figure 5This is a flowchart illustrating the relationship between calibrated dark current and temperature, provided in an embodiment of this application. This application also provides a dark current calibration method, including:

[0096] S510, under the first temperature condition, turns off the input optical power of the receiver and records the reading of the analog-to-digital converter at this time as the dark current reference at room temperature.

[0097] S520, under the second temperature condition, turns off the input optical power of the receiver and records the reading of the analog-to-digital converter at this time to obtain the dark current value at low temperature.

[0098] S530, under the third temperature condition, shuts off the input optical power of the receiver and records the reading of the analog-to-digital converter at this time to obtain the dark current value at high temperature.

[0099] S540 performs multiple fitting operations on the analog-to-digital converter readings corresponding to the dark current obtained under the first, second, and third temperature conditions and the corresponding temperatures to obtain a model of the relationship between dark current and temperature.

[0100] The first temperature, the second temperature, and the third temperature are different.

[0101] For example, the first temperature refers to normal temperature, such as between approximately 20°C and 25°C; the second temperature refers to low temperature, such as below 0°C; and the third temperature refers to high temperature, such as above 40°C to 50°C. The specific temperature values ​​for the first, second, and third temperatures can be determined based on the actual situation.

[0102] In steps S510 to S540 above, S510, S520, and S530 respectively turn off the input optical power of the receiver and record the readings of the analog-to-digital converter under normal temperature, low temperature, and high temperature conditions, and the execution order is not limited. Through these steps, the dark current value at different temperatures can be obtained. S540 obtains a mathematical model by repeatedly fitting the dark current value obtained at different temperatures with the corresponding temperature. This model describes how the dark current changes with temperature, and represents the fitting results of the dark current value at different temperatures.

[0103] The purpose of the obtained model of the relationship between dark current and temperature is to predict the dark current value at the current temperature when the ambient temperature changes in practical applications, and to correct the basic threshold of signal loss accordingly, so as to ensure that the optical module can accurately detect signal loss under different temperature conditions, thereby improving the stability and reliability of the optical module.

[0104] Please refer to Figure 6 , Figure 6 This is a flowchart of the calculation of the dynamic threshold for signal loss provided in an embodiment of this application. Figure 6The following illustrates the process in a practical application where the comparator outputs a signal loss indication signal based on a dynamic signal loss threshold:

[0105] S610, read the previously calibrated basic threshold for signal loss:

[0106] In this step, the MCU reads the pre-calibrated baseline signal loss threshold held in a register. The baseline signal loss threshold represents the ideal signal loss threshold without the influence of dark current.

[0107] S620, calculates the dark current value at the current temperature.

[0108] In this step, the MCU uses a pre-established model of the relationship between dark current and temperature to calculate an estimated value of dark current based on the current ambient temperature, and then converts it into a digital signal using an analog-to-digital converter.

[0109] S630 uses the sum of the basic signal loss threshold and the dark current value at the current temperature as the dynamic threshold for signal loss.

[0110] In this step, the MCU adds the basic signal loss threshold read in step S610 to the dark current value calculated in step S620 to obtain a dynamic signal loss threshold that takes into account the influence of dark current. This dynamic signal loss threshold reflects that, at the current temperature, the detection module will only trigger the signal loss indication signal when the light signal intensity is below a certain level.

[0111] S640 determines whether the current voltage received by the comparator is less than the signal loss dynamic threshold.

[0112] In this step, the MCU compares the analog-to-digital converter reading (i.e., the actual received optical signal strength) with the signal loss dynamic threshold calculated in S630. If the analog-to-digital converter reading is less than the signal loss dynamic threshold, it means that the optical signal strength has fallen below the preset threshold, and S650 is executed; otherwise, the MCU repeats this judgment step until the analog-to-digital converter reading is less than the signal loss dynamic threshold.

[0113] S650, the comparator output signal lost the indication signal, and triggered the MCU to output an interrupt indication signal.

[0114] If the condition in S640 is met (i.e., the reading of the analog-to-digital converter is less than the signal loss dynamic threshold), the comparator will output a signal loss indication signal. This signal loss indication signal will trigger the MCU's interrupt mechanism and output an interrupt indication signal through the interrupt controller to notify the system that a signal loss event has occurred.

[0115] In S610 to S640 above, it is ensured that the optical module can accurately detect signal loss under different temperature conditions, and compensate for the influence of dark current by adjusting the dynamic threshold of signal loss in real time, thereby improving the stability and reliability of the optical module.

[0116] In summary, this application provides an optical module optical signal loss processing circuit and method, which achieves microsecond-level fast response, flexible setting of initial signal loss value, effective compensation for drift caused by dark current, setting bias voltage to reduce the requirements on operational amplifier performance, and simplifies the calibration process of the basic threshold for signal loss. This improves the speed, accuracy, and flexibility of signal loss detection, while reducing costs and simplifying the operation process, thus contributing to the improvement of the overall performance and reliability of the optical module.

[0117] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An optical module optical signal loss processing circuit, characterized by, The circuit includes: The conversion module is used to convert the current output by the photodetector into voltage, and then add a preset bias voltage to the converted voltage to obtain the current voltage; The detection module is used to compare the current voltage with the signal loss dynamic threshold. If the current voltage is lower than the signal loss dynamic threshold, a signal loss indication signal is output. The signal loss dynamic threshold is a dynamic value, which includes the calibrated signal loss base threshold and the dark current value fitted at the current temperature. The signal loss dynamic threshold is obtained by adding the signal loss base threshold and the dark current value fitted at the current temperature. The control module is used to output an interruption indication signal based on the received signal loss indication signal; and to obtain the signal loss dynamic threshold based on calibration and the current temperature.

2. The optical module optical signal loss processing circuit according to claim 1, characterized by, The conversion module includes a transimpedance amplifier, a first resistor, and a second resistor. The transimpedance amplifier is used to convert the current output by the photodetector into a voltage. One end of the first resistor and the second resistor connected in series is connected to a first power supply, and the other end is grounded. The connection node between the first resistor and the second resistor is connected to the output terminal of the transimpedance amplifier, so that the voltage output by the transimpedance amplifier is superimposed with the bias voltage provided by the first power supply to obtain the current voltage.

3. The optical module optical signal loss processing circuit according to claim 2, characterized in that, The conversion module includes a first node, a second node, and a third node. The conversion module also includes a first capacitor with a first terminal and a second terminal. The first terminal of the first capacitor is connected to the first node. The connection node between the first resistor and the second resistor serves as the second node and is connected to the first node. The third node is connected to the detection module and the control module, respectively.

4. The optical module optical signal loss processing circuit according to claim 3, characterized in that, The detection module includes a fourth node, a comparator, a third resistor, a fourth resistor, and a fifth resistor; the comparator has a positive input terminal, a negative input terminal, and an output terminal; the third resistor has a first terminal and a second terminal, the first terminal of the third resistor is connected to the third node, and the second terminal of the third resistor is connected to the negative input terminal of the comparator; the fourth resistor has a first terminal and a second terminal, the first terminal of the fourth resistor is connected to the output terminal of the signal loss dynamic threshold, and the second terminal of the fourth resistor is connected to the positive input terminal of the comparator through the fourth node; the fifth resistor has a first terminal and a second terminal, the first terminal of the fifth resistor is connected to the fourth node, and the second terminal of the fifth resistor is connected to the output terminal of the comparator.

5. The optical module optical signal loss processing circuit according to claim 4, characterized in that, The detection module further includes a second capacitor, and the comparator also has a positive power supply terminal and a negative power supply terminal; the positive power supply terminal of the comparator is connected to a second power supply, and the negative power supply terminal is grounded; the second capacitor has a first terminal and a second terminal, the first terminal of the second capacitor is connected to the second power supply, and the second terminal of the second capacitor is grounded.

6. The optical module optical signal loss processing circuit according to claim 5, characterized in that, The control module is used to evaluate the input optical power based on the sampled current voltage and report the evaluation result. It includes an analog-to-digital converter, a digital-to-analog converter, and an interrupt controller. The analog-to-digital converter is connected to the third node and is used to convert the sampled current voltage analog signal into a digital signal. The digital-to-analog converter is used to output the signal loss dynamic threshold. The interrupt controller is connected to the output of the comparator. When the comparator outputs the signal loss indication signal, the interrupt controller outputs an interrupt indication signal.

7. The optical module optical signal loss processing circuit according to claim 4, characterized in that, The fourth resistor and the fifth resistor are used to configure the hysteresis voltage threshold of the comparator. The hysteresis voltage threshold is equal to the difference between the positive power supply voltage and the negative power supply voltage of the comparator, multiplied by the proportion of the resistance of the fourth resistor in the series circuit composed of the fourth resistor and the fifth resistor.

8. A method for handling optical signal loss in an optical module, characterized in that, The method includes: The current output by the photodetector is converted into voltage, and a preset bias voltage is added to the converted voltage to obtain the current voltage; The current voltage is compared with the signal loss dynamic threshold. If the current voltage is lower than the signal loss dynamic threshold, a signal loss indication signal is output. The signal loss dynamic threshold is a dynamic value, obtained by calibration and in combination with the current temperature. The signal loss dynamic threshold includes the calibrated signal loss base threshold and the dark current value fitted at the current temperature. The signal loss dynamic threshold is obtained by adding the signal loss base threshold and the dark current value fitted at the current temperature. Based on the received signal loss indication signal, an interrupt indication signal is output.

9. The optical module optical signal loss processing method according to claim 8, characterized in that, The steps for calibrating the basic threshold for signal loss include: The control module receives a signal loss debugging command from the automatic testing system to instruct the execution of a signal loss debugging operation. The control module includes an analog-to-digital converter and a digital-to-analog converter. The input optical power currently received by the analog-to-digital converter is used as the initial value of signal loss for the digital-to-analog converter, and the initial value of signal loss is adjusted to obtain the target value of signal loss. The fitted dark current value at the current temperature is calculated using a pre-calibrated model of the relationship between dark current and temperature. The dark current value is then subtracted from the target value of signal loss to obtain the basic threshold for signal loss.

10. The optical module optical signal loss processing method according to claim 9, characterized in that, The step of adjusting the initial value of signal loss to obtain the target value of signal loss includes: Determine whether the detection module outputs a signal loss indication signal because the reported input optical power is lower than the initial value of the signal loss; If the detection module does not output the signal loss indication signal, the initial value of the signal loss is gradually increased to obtain the corresponding current value of the signal loss. Once the detection module outputs the signal loss indication signal, the current signal loss value is taken as the signal loss target value, which includes the dark current value fitted at the current temperature.

11. The optical module optical signal loss processing method according to claim 9, characterized in that, The steps for calibrating the model of the relationship between dark current and temperature include: Under the first temperature condition, the input optical power of the receiver is turned off, and the reading of the analog-to-digital converter at this time is recorded as the dark current reference at room temperature; Under the second temperature condition, the input optical power of the receiver is turned off, and the reading of the analog-to-digital converter is recorded at this time to obtain the dark current value at low temperature; Under the third temperature condition, the input optical power of the receiver is turned off, and the reading of the analog-to-digital converter is recorded at this time to obtain the dark current value at high temperature; The analog-to-digital converter readings corresponding to the dark current obtained at the first temperature, the second temperature, and the third temperature are fitted multiple times with the corresponding temperatures to obtain a model of the relationship between the dark current and the temperature. The first temperature, the second temperature, and the third temperature are different.

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