Coherent optical module optical power calibration method and device, coherent optical module and medium

Abstract

The application provides a coherent optical module optical power calibration method and device, a coherent optical module and a medium, and relates to the technical field of optical communication.In the transmitting end, a responsivity lookup table is formed based on the responsivity of each transmitting light path under different working conditions, and the target sampling voltage corresponding to each transmitting light path is calculated in combination with the dark light voltage and the target value of the transmitting optical power, the gain of the feedback adjustment driver is adjusted, the power accuracy can be ensured, the modulation signals on each transmitting light path can be kept balanced, the joint calibration of the power and the signal quality is realized.In the receiving end, the corresponding relationship between the gain control voltage average value and the received optical power is established, the reference received optical power is obtained, and the accurate actual received optical power can be obtained in combination with the received optical power error under different working conditions in the power error lookup table; the method does not need to additionally configure a photoelectric detector on each received light path, and the chip volume and the design complexity are reduced.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and more specifically, to a method, apparatus, coherent optical module, and medium for calibrating optical power of a coherent optical module. Background Technology

[0002] With the rapid development of coherent optical communication technology, complex high-order modulation formats such as DP-16QAM (dual-polarization 16th-order quadrature amplitude modulation) are widely used in optical modules to carry more bits of information in a single symbol. The transmitter of a coherent optical module uses an In-Phase / Quadrature (IQ) Mach-Zehnder modulator to generate complex modulation signals, while the receiver uses coherent reception technology to mix the signal light with the local oscillator light generated by a local laser, thereby recovering the amplitude, phase, and polarization state information of the optical signal. These coherent optical modules support C-band tunable wavelengths, allowing for arbitrary wavelength configuration on the ITU-T G694 standard channel grid, driving the development of metropolitan area and data center interconnection networks towards longer distances and higher densities.

[0003] In the manufacturing and use of coherent optical modules, accurate power calibration is a key technical step to ensure reliable operation and interoperability. The transmitted optical power must be stabilized within an optimal range to ensure sufficient link budget without damaging the receiver at the other end. The receiver also needs to accurately sense the input optical power so that the digital signal processor (DSP) can adjust gain and equalization parameters. Power calibration is typically not a one-time factory setting but requires dynamic adjustment based on temperature. The coherent optical module needs to monitor its internal temperature in real time and adjust the transmitted optical power or interpret the received optical power readings according to a preset calibration curve (Look-Up Table, LUT). Digital Diagnostic Monitoring (DDM) and the Common Management Interface Specification (CMIS) provide standardized interfaces for storing and accessing calibration data.

[0004] Existing calibration methods typically perform this on the production line, writing unique calibration coefficients for each coherent optical module into an electrically erasable programmable read-only memory (EEPROM). During runtime, the firmware uses these coefficients to convert the raw analog-to-digital converter (ADC) readings into accurate physical quantities (dBm). Due to the inherent discreteness in manufacturing processes, each coherent optical module must be individually calibrated to ensure that the output specifications of all modules conform to a unified standard (such as ITU-T G.698.2), enabling interoperability between modules from different manufacturers.

[0005] However, existing calibration methods have certain drawbacks: at the transmitting end, they typically rely solely on the photodetector built into the main path to monitor the total output optical power, lacking a mechanism for detecting and feeding back the output optical signals on each arm of the modulator (corresponding to multiple transmitting optical paths), making it difficult to guarantee the accuracy of the transmitted optical power. At the receiving end, additional photodetectors are usually required on each receiving optical path, which significantly increases the chip size and complexity. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a coherent optical module optical power calibration method, apparatus, coherent optical module and medium to solve the problems of low accuracy, large chip size and high complexity of existing calibration methods.

[0007] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0008] In a first aspect, the present invention provides a method for calibrating the optical power of a coherent optical module, including a transmit optical power calibration step and / or a receive optical power calibration step.

[0009] The emitted optical power calibration step includes:

[0010] Based on the current operating conditions of the coherent optical module and the responsivity lookup table, the target responsivity of each emission optical path of the coherent optical module under the current operating conditions is obtained; the responsivity lookup table records the responsivity of each emission optical path of the coherent optical module under different operating conditions.

[0011] Obtain the dark light voltage of each of the aforementioned emission optical paths under the current operating conditions;

[0012] Calculate the target sampling voltage corresponding to the photodetector of each of the aforementioned optical paths based on the target responsivity, dark light voltage, and target value of the emitted light power.

[0013] The gain of the driver of each of the transmitting optical paths is adjusted according to the current sampling voltage and the target sampling voltage of the photodetector of each transmitting optical path, so that the current sampling voltage is consistent with the target sampling voltage;

[0014] The received optical power calibration step includes:

[0015] Based on the current operating conditions of the coherent optical module and the power error lookup table, the target received optical power error of the coherent optical module under the current operating conditions is obtained; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions.

[0016] Obtain the average real-time gain control voltage of each receiving optical path output by the transimpedance amplifier of the coherent optical module;

[0017] According to the real-time gain control voltage average value and the received optical power lookup table, the reference received optical power corresponding to the real-time gain control voltage average value is obtained; the received optical power lookup table records the correspondence between the gain control voltage average value and the received optical power under preset operating conditions.

[0018] The actual received optical power of the coherent optical module is obtained based on the error between the reference received optical power and the received optical power.

[0019] In an optional implementation, the operating conditions include operating temperature and operating wavelength; obtaining the target responsivity of each emission path of the coherent optical module under the current operating conditions according to the current operating conditions and responsivity lookup table of the coherent optical module includes:

[0020] The first and second operating temperatures corresponding to the current operating temperature of the coherent optical module, and the first and second operating wavelengths corresponding to the current operating wavelength of the coherent optical module, are determined from multiple operating temperatures and multiple operating wavelengths recorded in the responsivity lookup table. The first responsivity, the second responsivity, the third responsivity, and the fourth responsivity of each transmitting optical path at the first operating temperature and the first operating wavelength are obtained. The first and second operating temperatures are adjacent, and the current operating temperature is between the first and second operating temperatures. The first and second operating wavelengths are adjacent, and the current operating wavelength is between the first and second operating wavelengths.

[0021] For each of the aforementioned optical transmission paths, based on the first operating temperature, the second operating temperature, the current operating temperature, the first responsivity, the second responsivity, the third responsivity, and the fourth responsivity corresponding to the optical transmission path, a first reference responsivity of the optical transmission path at the current operating temperature and the first operating wavelength, and a second reference responsivity at the current operating temperature and the second operating wavelength are calculated.

[0022] Based on the first operating wavelength, the second operating wavelength, the current operating wavelength, the first reference responsivity, and the second reference responsivity, the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength is calculated.

[0023] In an optional implementation, the step of calculating a first reference responsivity of the transmitting optical path at the current operating temperature and the first operating wavelength, and a second reference responsivity at the current operating temperature and the second operating wavelength, based on the first operating temperature, the second operating temperature, the current operating temperature, the first responsivity, the second responsivity, the third responsivity, and the fourth responsivity corresponding to the transmitting optical path, includes:

[0024] Calculate the first temperature difference between the current operating temperature and the first operating temperature, and the second temperature difference between the second operating temperature and the first operating temperature;

[0025] Calculate the first ratio of the first temperature difference to the second temperature difference;

[0026] Calculate the first response difference between the third response and the first response;

[0027] Multiply the first ratio by the first responsivity difference and add it to the first responsivity to obtain the first reference responsivity of the emitted optical path at the current operating temperature and the first operating wavelength;

[0028] Calculate the second response difference between the fourth response and the second response;

[0029] Multiply the first ratio by the second responsivity difference and add it to the second responsivity to obtain the second reference responsivity of the emitted optical path at the current operating temperature and the second operating wavelength.

[0030] In an optional implementation, calculating the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength based on the first operating wavelength, the second operating wavelength, the current operating wavelength, the first reference responsivity, and the second reference responsivity includes:

[0031] Calculate the first wavelength difference between the current operating wavelength and the first operating wavelength, and the second wavelength difference between the second operating wavelength and the first operating wavelength;

[0032] Calculate the second ratio of the first wavelength difference to the second wavelength difference;

[0033] Calculate the reference response difference between the second reference response and the first reference response;

[0034] Multiplying the second ratio by the difference between the reference responsivity and adding it to the first reference responsivity yields the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength.

[0035] In an optional implementation, the step of calculating the target sampling voltage corresponding to the photodetector of each of the emitted optical paths based on the target responsivity, dark light voltage, and target emitted light power of each of the emitted optical paths includes:

[0036] The theoretical sampling voltage is calculated based on the target responsivity of the transmitted optical path, the target value of the transmitted optical power, and the preset sampling resistor; the theoretical sampling voltage is the voltage generated by light.

[0037] The theoretical sampling voltage is added to the dark light voltage to obtain the target sampling voltage corresponding to the photodetector in the emission optical path.

[0038] In an optional implementation, the operating conditions include operating temperature and operating wavelength; obtaining the target received optical power error of the coherent optical module under the current operating conditions based on the current operating conditions of the coherent optical module and a power error lookup table includes:

[0039] The third and fourth operating temperatures corresponding to the current operating temperature of the coherent optical module, and the third and fourth operating wavelengths corresponding to the current operating wavelength of the coherent optical module, are determined from multiple operating temperatures and multiple operating wavelengths recorded in the power error lookup table. The first power error, the second power error, the third power error, and the fourth power error of the coherent optical module at the third operating temperature and the third operating wavelength are obtained. The third and fourth operating temperatures are adjacent, and the current operating temperature is between the third and fourth operating temperatures. Similarly, the third and fourth operating wavelengths are adjacent, and the current operating wavelength is between the third and fourth operating wavelengths.

[0040] Based on the third operating temperature, the fourth operating temperature, the current operating temperature, the first power error, the second power error, the third power error, and the fourth power error, calculate the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength, and the second reference power error at the current operating temperature and the fourth operating wavelength;

[0041] Based on the third operating wavelength, the fourth operating wavelength, the current operating wavelength, the first reference power error, and the second reference power error, the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength is calculated.

[0042] In an optional implementation, the step of calculating the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength, and the second reference power error at the current operating temperature and the fourth operating wavelength, based on the third operating temperature, the fourth operating temperature, the current operating temperature, the first power error, the second power error, the third power error, and the fourth power error, includes:

[0043] Calculate the third temperature difference between the current operating temperature and the third operating temperature, and the fourth temperature difference between the fourth operating temperature and the third operating temperature;

[0044] Calculate the third ratio of the third temperature difference to the fourth temperature difference;

[0045] Calculate the first power error difference between the third power error and the first power error;

[0046] Multiplying the third ratio by the first power error difference and then adding it to the first power error, we obtain the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength.

[0047] Calculate the second power error difference between the fourth power error and the second power error;

[0048] Multiplying the third ratio by the second power error difference and then adding it to the second power error yields the second reference power error of the coherent optical module at the current operating temperature and the fourth operating wavelength.

[0049] In an optional implementation, calculating the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength based on the third operating wavelength, the fourth operating wavelength, the current operating wavelength, the first reference power error, and the second reference power error includes:

[0050] Calculate the third wavelength difference between the current operating wavelength and the third operating wavelength, and the fourth wavelength difference between the fourth operating wavelength and the third operating wavelength;

[0051] Calculate the fourth ratio of the third wavelength difference to the fourth wavelength difference;

[0052] Calculate the reference power error difference between the second reference power error and the first reference power error;

[0053] Multiplying the fourth ratio by the difference in reference power error and then adding it to the first reference power error yields the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength.

[0054] In an optional implementation, obtaining the reference received optical power corresponding to the average real-time gain control voltage based on the lookup table of the average real-time gain control voltage and the received optical power includes:

[0055] The first average gain control voltage and the second average gain control voltage corresponding to the real-time average gain control voltage are determined from multiple average gain control voltage values ​​recorded in the received optical power lookup table, and the first received optical power corresponding to the first average gain control voltage and the second received optical power corresponding to the second average gain control voltage are obtained; the first average gain control voltage and the second average gain control voltage are adjacent and the real-time average gain control voltage is between the first average gain control voltage and the second average gain control voltage;

[0056] Calculate the first voltage difference between the average real-time gain control voltage and the average first gain control voltage, and the second voltage difference between the average first gain control voltage and the average second gain control voltage;

[0057] Calculate the fifth ratio of the first voltage difference to the second voltage difference;

[0058] Calculate the difference in received optical power between the first received optical power and the second received optical power;

[0059] Multiplying the fifth ratio by the difference in received optical power and then adding it to the first received optical power yields the reference received optical power corresponding to the average real-time gain control voltage.

[0060] In a second aspect, the present invention provides a coherent optical module optical power calibration device, including a transmit optical power calibration module and / or a receive optical power calibration module;

[0061] The transmitted optical power calibration module includes:

[0062] The responsivity acquisition unit is used to acquire the target responsivity of each emission optical path of the coherent optical module under the current operating conditions based on the current operating conditions of the coherent optical module and a responsivity lookup table; the responsivity lookup table records the responsivity of each emission optical path of the coherent optical module under different operating conditions.

[0063] Dark light voltage acquisition unit, used to acquire the dark light voltage of each of the emitted optical paths under the current operating conditions;

[0064] The target sampling voltage calculation unit is used to calculate the target sampling voltage corresponding to the photodetector of each of the emission optical paths based on the target responsivity, dark light voltage and target value of emission light power of each of the emission optical paths;

[0065] The transmit optical power control unit is used to adjust the gain of the driver of each transmit optical path according to the current sampling voltage and the target sampling voltage of the photodetector of each transmit optical path, so that the current sampling voltage is consistent with the target sampling voltage;

[0066] The received optical power calibration module includes:

[0067] The optical power error acquisition unit is used to acquire the target received optical power error of the coherent optical module under the current operating conditions based on the current operating conditions of the coherent optical module and a power error lookup table; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions.

[0068] The voltage average acquisition unit is used to acquire the real-time gain control voltage average of each receiving optical path output by the transimpedance amplifier of the coherent optical module.

[0069] The received optical power calculation unit is used to obtain the reference received optical power corresponding to the average real-time gain control voltage according to the average real-time gain control voltage and the received optical power lookup table; the received optical power lookup table records the correspondence between the average gain control voltage and the received optical power under preset operating conditions; and obtain the actual received optical power of the coherent optical module according to the error between the reference received optical power and the received optical power.

[0070] Thirdly, the present invention provides a coherent optical module, including a processor, wherein the processor executes a computer program to implement the steps of the coherent optical module optical power calibration method as described in any of the foregoing embodiments.

[0071] Fourthly, the present invention provides a computer-readable storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the coherent optical module optical power calibration method as described in any of the foregoing embodiments.

[0072] The coherent optical module optical power calibration method, apparatus, coherent optical module, and medium provided in this invention, at the transmitting end, form a responsivity lookup table based on the responsivity of each transmitting optical path under different operating conditions, thereby obtaining the target responsivity of each transmitting optical path under various operating conditions. Combined with the dark light voltage and target transmitted optical power value of each transmitting optical path under these operating conditions, the target sampling voltage corresponding to the photodetector of each transmitting optical path can be obtained. Then, based on the current sampling voltage and the target sampling voltage, the gain of the driver of each transmitting optical path is adjusted, ensuring both power accuracy and maintaining the balance of the modulation signal on each transmitting optical path, achieving joint calibration of power and signal quality. At the receiving end, a power error lookup table is formed based on the received optical power error of the coherent optical module under different operating conditions, allowing the acquisition of the target received optical power error of the coherent optical module under various operating conditions. Based on the correspondence between the average gain control voltage and the received optical power, the reference received optical power corresponding to the average real-time gain control voltage can be obtained. Combined with the corresponding target received optical power error, the actual received optical power can be obtained. This method does not require additional photodetectors on each receiving optical path, reducing chip size and design complexity.

[0073] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0074] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0075] Figure 1 This invention provides a schematic flowchart of a coherent optical module optical power calibration method according to an embodiment of the present invention.

[0076] Figure 2 A system architecture diagram applicable to embodiments of the present invention is shown;

[0077] Figure 3 The diagram shows the structural block diagram of the transmitter in the coherent optical module;

[0078] Figure 4 A functional block diagram of a coherent optical module optical power calibration device provided in an embodiment of the present invention is shown.

[0079] Icons: 400 - Coherent optical module optical power calibration device; 410 - Transmit optical power calibration module; 420 - Receive optical power calibration module; 411 - Responsivity acquisition unit; 412 - Dark light voltage acquisition unit; 413 - Target sampling voltage calculation unit; 414 - Transmit optical power control unit; 421 - Optical power error acquisition unit; 422 - Voltage average acquisition unit; 423 - Receive optical power calculation unit. Detailed Implementation

[0080] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0081] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0082] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0083] In existing technologies, transmitter power calibration typically involves detecting and reporting optical signals using a photodetector integrated into the main circuit under different temperature and wavelength conditions, while simultaneously recording the actual output optical power. After all calibration points are recorded, a lookup table is formed and written to the calibration register. Receiver power calibration, on the other hand, requires detecting and reporting multiple received optical signals using a photodetector integrated into the optical path of the receiver chip under different temperature and wavelength conditions, calculating the offset under each condition, forming a lookup table, and writing it to the calibration register.

[0084] However, existing transmitter calibration methods lack a feedback mechanism for the output optical signal on each arm of the modulator, making it impossible to dynamically adjust the driver gain and thus difficult to achieve joint calibration of power and signal quality. Receiver calibration methods require integrating photodetectors on each arm of the receiver, increasing chip size and complexity. Furthermore, existing methods require transceiver calibration for multiple wavelengths, resulting in low debugging efficiency.

[0085] Based on this, this invention proposes a method, apparatus, coherent optical module, and medium for calibrating the optical power of a coherent optical module. At the transmitting end, a responsivity lookup table is formed based on the responsivity of each transmitting optical path under different operating conditions. This allows the acquisition of the target responsivity of each transmitting optical path under various operating conditions. Combined with the dark light voltage and target transmitted optical power value of each transmitting optical path under these conditions, the target sampling voltage corresponding to the photodetector of each transmitting optical path can be obtained. Then, the gain of the driver for each transmitting optical path is adjusted based on the current sampling voltage and the target sampling voltage, ensuring both power accuracy and maintaining the balance of the modulation signals on each transmitting optical path, achieving joint calibration of power and signal quality. At the receiving end, a power error lookup table is formed based on the received optical power error of the coherent optical module under different operating conditions. This allows the acquisition of the target received optical power error of the coherent optical module under various operating conditions. Based on the correspondence between the average gain control voltage and the received optical power, the reference received optical power corresponding to the average real-time gain control voltage can be obtained. Combined with the corresponding target received optical power error, the actual received optical power can be obtained. This method does not require additional photodetectors on each receiving optical path, reducing chip size and design complexity.

[0086] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0087] Please refer to Figure 1 This is a schematic flowchart illustrating a coherent optical module optical power calibration method provided in an embodiment of the present invention. It should be noted that the coherent optical module optical power calibration method of the present invention does not rely on... Figure 1 The specific order described below is a limitation. It should be understood that in other embodiments, the order of some steps in the coherent optical module optical power calibration method of the present invention can be interchanged according to actual needs, or some steps can be omitted or deleted. The executing entity of this coherent optical module optical power calibration method can be a coherent optical module. The following will describe... Figure 1 The specific process shown will be explained in detail.

[0088] In this embodiment, the coherent optical module optical power calibration method includes a transmit optical power calibration step S1 and / or a receive optical power calibration step S2. The transmit optical power calibration step S1 mainly includes steps S101 to S104, and the receive optical power calibration step S2 mainly includes steps S201 to S204.

[0089] The following is a detailed explanation of steps S101 to S104.

[0090] Step S101: Based on the current operating conditions of the coherent optical module and the responsivity lookup table, obtain the target responsivity of each transmitting optical path of the coherent optical module under the current operating conditions; the responsivity lookup table records the responsivity of each transmitting optical path of the coherent optical module under different operating conditions.

[0091] In this embodiment, by testing each transmitting optical path of the coherent optical module under multiple operating conditions, the responsivity of each transmitting optical path of the coherent optical module under different operating conditions is obtained, forming a responsivity lookup table. During the operation of the coherent optical module, the responsivity lookup table is searched according to the current operating conditions of the coherent optical module, and the target responsivity of each transmitting optical path of the coherent optical module under the current operating conditions can be obtained based on the searched responsivity data.

[0092] Step S102: Obtain the dark light voltage of each emitting optical path under the current operating conditions.

[0093] In this embodiment, dark light voltage refers to the voltage generated by the photodetectors on each transmitting optical path under no-light conditions due to the thermal excitation effect of the semiconductor material itself and circuit noise. For each transmitting optical path, dark light voltage under different operating conditions can be collected, and then the corresponding dark light voltage calculation formula can be obtained by fitting. During the operation of the coherent optical module, based on the dark light voltage calculation formula corresponding to each transmitting optical path and the current operating conditions, the dark light voltage of that transmitting optical path under the current operating conditions can be calculated.

[0094] In one implementation, the operating conditions of the coherent optical module mainly include operating temperature and operating wavelength, while the dark light voltage is primarily temperature-dependent. Therefore, in this embodiment, multiple sets of dark light voltage data at different temperatures can be collected for each transmitting optical path. An exponential fitting is then performed with temperature as the independent variable to obtain an exponential function model of the dark light voltage change with temperature (i.e., the dark light voltage calculation formula). In this way, the dark light voltage corresponding to each transmitting optical path under any temperature condition can be calculated.

[0095] Step S103: Calculate the target sampling voltage corresponding to the photodetector of each transmitting optical path based on the target responsivity, dark light voltage and target value of the transmitted light power of each transmitting optical path.

[0096] In this embodiment, the dark light voltage is considered when calculating the target sampling voltage, which can eliminate the influence of dark current and ensure calibration accuracy.

[0097] Step S104: Adjust the gain of the driver of each transmitting optical path according to the current sampling voltage and target sampling voltage of the photodetector of each transmitting optical path so that the current sampling voltage is consistent with the target sampling voltage.

[0098] In this embodiment, by continuously comparing the current sampling voltage and the target sampling voltage of each transmitting optical path, the gain of the driver of each transmitting optical path is dynamically adjusted based on the error between the two until the current sampling voltage matches the target sampling voltage. This closed-loop feedback control method for each transmitting optical path effectively ensures the accuracy of the transmitted optical power and keeps the modulation signals on each transmitting optical path balanced, achieving joint calibration of power and signal quality.

[0099] Next, the contents of steps S201 to S204 will be explained in detail.

[0100] Step S201: Based on the current operating conditions of the coherent optical module and the power error lookup table, obtain the target received optical power error of the coherent optical module under the current operating conditions; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions.

[0101] In this embodiment, the received optical power error of the coherent optical module under multiple different operating conditions can be measured in advance to form a power error lookup table. During the operation of the coherent optical module, the power error lookup table is consulted according to the current operating conditions of the coherent optical module. Based on the retrieved received optical power error data, the target received optical power error of the coherent optical module under the current operating conditions can be obtained.

[0102] Step S202: Obtain the average real-time gain control voltage of each receiving optical path output by the transimpedance amplifier of the coherent optical module.

[0103] In this embodiment, the average real-time gain control voltage can be obtained by calculating the average value of the real-time gain control voltage of each receiving optical path based on the output of the transimpedance amplifier.

[0104] Step S203: Obtain the reference received optical power corresponding to the average real-time gain control voltage according to the lookup table of average real-time gain control voltage and received optical power; the lookup table of received optical power records the correspondence between the average gain control voltage and received optical power under preset operating conditions.

[0105] In this embodiment, the average gain control voltage of the coherent optical module at different received optical powers can be recorded under preset operating conditions. A received optical power lookup table is formed based on the correspondence between multiple sets of recorded average gain control voltages and received optical powers. During the operation of the coherent optical module, the received optical power lookup table is consulted based on the acquired real-time average gain control voltage. The reference received optical power corresponding to the real-time average gain control voltage can be obtained based on the found received optical power data.

[0106] Step S204: Obtain the actual received optical power of the coherent optical module based on the reference received optical power and the received optical power error.

[0107] In this embodiment, the actual received optical power of the coherent optical module can be obtained by correcting the reference received optical power based on the received optical power error.

[0108] As can be seen, the coherent optical module optical power calibration method provided in this embodiment of the invention, at the transmitting end, forms a responsivity lookup table based on the responsivity of each transmitting optical path under different operating conditions, thereby obtaining the target responsivity of each transmitting optical path under various operating conditions. Combined with the dark light voltage and target transmitted optical power value of each transmitting optical path under these operating conditions, the target sampling voltage corresponding to the photodetector of each transmitting optical path can be obtained. Then, based on the current sampling voltage and the target sampling voltage, the gain of the driver of each transmitting optical path is adjusted, ensuring both power accuracy and maintaining the balance of the modulation signal on each transmitting optical path, achieving joint calibration of power and signal quality. At the receiving end, a power error lookup table is formed based on the received optical power error of the coherent optical module under different operating conditions, thereby obtaining the target received optical power error of the coherent optical module under various operating conditions. Based on the correspondence between the average gain control voltage and the received optical power, the reference received optical power corresponding to the average real-time gain control voltage can be obtained. Combined with the corresponding target received optical power error, the actual received optical power can be obtained. This method does not require additional photodetectors on each receiving optical path, reducing chip size and design complexity.

[0109] In practical applications, theoretically, coherent optical modules can be tested under numerous temperature and wavelength conditions on the production line, generating responsivity lookup tables, power error lookup tables, and received optical power lookup tables that essentially cover the entire temperature and wavelength range. However, this approach is inefficient, significantly reducing production efficiency. Therefore, in this embodiment, during production testing, only a small number of temperature and wavelength points need to be selected within a preset temperature range (e.g., -5℃ to 75℃) and a preset wavelength range (e.g., 191.3THz to 196.1THz) to complete basic data acquisition and construct the responsivity lookup table, power error lookup table, and received optical power lookup table. During actual power calibration, power calibration under arbitrary temperature and wavelength conditions can be achieved based on a linear interpolation algorithm. This method significantly reduces the number of calibration points in production testing, lowers testing time and cost, while still ensuring calibration accuracy.

[0110] In one embodiment, step S101 specifically includes:

[0111] The first and second operating temperatures corresponding to the current operating temperature of the coherent optical module, and the first and second operating wavelengths corresponding to the current operating wavelength of the coherent optical module, are determined from multiple operating temperatures and multiple operating wavelengths recorded in the responsivity lookup table. The first responsivity, the second responsivity, the third responsivity, and the fourth responsivity of each transmitting optical path at the first operating temperature and the first operating wavelength are obtained. The first and second operating temperatures are adjacent, and the current operating temperature is between the first and second operating temperatures. The operating wavelength and the second operating wavelength are adjacent, and the current operating wavelength is between the first operating wavelength and the second operating wavelength. For each transmitting optical path, based on the first operating temperature, the second operating temperature, the current operating temperature, and the first, second, third, and fourth responsivity corresponding to the transmitting optical path, the first reference responsivity of the transmitting optical path at the current operating temperature and the first operating wavelength, and the second reference responsivity at the current operating temperature and the second operating wavelength are calculated. Based on the first operating wavelength, the second operating wavelength, the current operating wavelength, the first reference responsivity, and the second reference responsivity, the target responsivity of the transmitting optical path at the current operating temperature and the current operating wavelength is calculated.

[0112] In this embodiment, when the coherent optical module operates at a specific operating temperature and wavelength, the two operating temperatures closest to and adjacent to the current operating temperature of the coherent optical module are first determined from multiple operating temperatures and wavelengths recorded in the responsivity lookup table. These two temperatures are the first and second operating temperatures, where the first operating temperature ≤ the current operating temperature ≤ the second operating temperature. Simultaneously, the two operating wavelengths closest to and adjacent to the current operating wavelength of the coherent optical module are determined. These two wavelengths are the first and second operating wavelengths, where the first operating wavelength ≤ the current operating wavelength ≤ the second operating wavelength. Subsequently, the first responsivity, the second responsivity, the third responsivity, and the fourth responsivity of each transmitting optical path under the first operating temperature and first operating wavelength conditions are obtained.

[0113] For each transmitting optical path, firstly, linear interpolation along the temperature dimension is performed on the first, second, third, and fourth responsivity to calculate the first reference responsivity of each transmitting optical path under the current operating temperature and first operating wavelength conditions, and the second reference responsivity under the current operating temperature and second operating wavelength conditions. Next, based on the obtained first and second reference responsivity, linear interpolation along the wavelength dimension is performed to finally obtain the target responsivity of each transmitting optical path under the current operating temperature and current operating wavelength conditions.

[0114] In one implementation, the above-described linear interpolation operation on the temperature dimension for the first, second, third, and fourth responsivity may specifically include:

[0115] Calculate the first temperature difference between the current operating temperature and the first operating temperature, and the second temperature difference between the second operating temperature and the first operating temperature; calculate the first ratio of the first temperature difference to the second temperature difference; calculate the first responsivity difference between the third responsivity and the first responsivity; multiply the first ratio by the first responsivity difference and add it to the first responsivity to obtain the first reference responsivity of the emitted optical path at the current operating temperature and the first operating wavelength; calculate the second responsivity difference between the fourth responsivity and the second responsivity; multiply the first ratio by the second responsivity difference and add it to the second responsivity to obtain the second reference responsivity of the emitted optical path at the current operating temperature and the second operating wavelength.

[0116] In this embodiment, the first ratio represents the positional relationship between the current operating temperature and the first and second operating temperatures. A linear interpolation operation along the temperature dimension is performed using this first ratio, the first responsivity, and the third responsivity to obtain the first reference influence. This first reference responsivity can be understood as an estimate of the responsivity of the emitted optical path under the current operating temperature and the first operating wavelength conditions. Similarly, a linear interpolation operation along the temperature dimension is performed using this first ratio, the second responsivity, and the fourth responsivity to obtain the second reference responsivity. This second reference responsivity can also be understood as an estimate of the responsivity of the emitted optical path under the current operating temperature and the second operating wavelength conditions.

[0117] In one implementation, based on the obtained first and second reference responsivity, a linear interpolation operation is performed along the wavelength dimension, specifically including:

[0118] Calculate the first wavelength difference between the current operating wavelength and the first operating wavelength, and the second wavelength difference between the second operating wavelength and the first operating wavelength; calculate the second ratio of the first wavelength difference to the second wavelength difference; calculate the reference responsivity difference between the second reference responsivity and the first reference responsivity; multiply the second ratio by the reference responsivity difference and add it to the first reference responsivity to obtain the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength.

[0119] In this embodiment, the second ratio represents the positional relationship between the current operating wavelength and the first and second operating wavelengths. By combining the second ratio, the first reference responsivity, and the second reference responsivity, a linear interpolation operation is performed in the wavelength dimension to finally obtain the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength.

[0120] As can be seen, the coherent optical module optical power calibration method provided in this embodiment of the invention does not require testing all possible temperature and wavelength conditions to construct a responsivity lookup table for the power calibration of the transmitter. It can select only a limited number of temperatures and wavelengths for testing. When actually calibrating the transmitted optical power of the coherent optical module, the target responsivity under any temperature and wavelength conditions can be obtained through two linear interpolation operations in the temperature and wavelength dimensions, effectively avoiding the production time consumption caused by intensive calibration of the entire temperature range and the entire wavelength range.

[0121] In one embodiment, step S103 specifically includes:

[0122] Based on the target responsivity of the transmitting optical path, the target value of the transmitted optical power, and the preset sampling resistor, the theoretical sampling voltage is calculated; the theoretical sampling voltage is the voltage generated by light; the theoretical sampling voltage is added to the dark light voltage to obtain the target sampling voltage corresponding to the photodetector of the transmitting optical path.

[0123] It is understood that in this embodiment, the theoretical sampling voltage without the influence of dark current is first calculated based on the target responsivity, the target value of the emitted light power, and the preset sampling resistor. However, in reality, it will be affected by dark current, that is, there is dark light voltage. Therefore, by adding the theoretical sampling voltage and the dark light voltage, the target sampling voltage corresponding to the photodetector of each emitted light path can be accurately obtained.

[0124] The following is an exemplary description of the construction process of the responsivity lookup table involved in the optical power calibration of the transmitter.

[0125] by Figure 2 and Figure 3 For example, for transmitter optical power calibration, the transmitter of the coherent optical module includes four transmit optical paths (XI / XQ / YI / YQ), each corresponding to a driver (Driver_XI, Driver_XQ, Driver_YI, Driver_YQ) and an MZM (Mach-Zehnder Modulator) (MZM_XI, MZM_XQ, MZM_YI, MZM_YQ). Each transmit optical path also has a corresponding photodetector (TX_MPD_XI, TX_MPD_XQ, TX_MPD_YI, TX_MPD_YQ) for voltage sampling. An ITLA (Integrated Tunable Laser Assembly) is a wavelength-tunable light source that provides optical signals to the transmitter, and these signals can also be used as local oscillation light for mixing at the receiver. The responsivity of each transmitting optical path was tested at four operating temperatures (-5℃, 25℃, 50℃, and 75℃) and seven operating wavelengths (191.3THz, 192.2THz, 192.95THz, 193.85THz, 194.6THz, 195.5THz, and 196.1THz). A responsivity lookup table was then created, enabling emission power calibration of each transmitting optical path across the entire temperature range (-5℃ to 75℃) and the entire wavelength range (191.3THz to 196.1THz). The specific process is as follows:

[0126] First, under the conditions of operating temperature -5℃ and operating wavelength 191.3THz, only the XI signal is turned on, while the XQ / YI / YQ signals are all turned off. Record the optical power meter reading XI-P11 / dBm and the MPD (Monitor Photodetector) sampling voltage XI-M11 / V of the XI channel (obtained through the MCU inside the coherent optical module). Repeat the above operation, turning on only one signal each time to complete the data acquisition of the XQ / YI / YQ channels respectively, and record them as XQ-P11 / dBm, YI-P11 / dBm, YQ-P11 / dBm, XQ-M11 / V, YI-M11 / V, YQ-M11 / V.

[0127] The second step involves maintaining a constant temperature of -5℃ and switching the operating wavelengths to 192.2THz, 192.95THz, 193.85THz, 194.6THz, 195.5THz, and 196.1THz respectively. Repeat the first step, recording the optical power meter readings and MPD sampling voltages at each operating wavelength, denoted as XI-P1x / dBm, XQ-P1x / dBm, YI-P1x / dBm, YQ-P1x / dBm, XI-M1x / V, XQ-M1x / V, YI-M1x / V, and YQ-M1x / V respectively. Here, x = 1, 2, 3, 4, 5, 6, and 7 correspond to the seven wavelengths: 191.3THz, 192.2THz, 192.95THz, 193.85THz, 194.6THz, 195.5THz, and 196.1THz.

[0128] The third step is to keep the temperature constant at -5℃, turn off all four signals, and record the MPD sampling voltages XI-D1 / V, XQ-D1 / V, YI-D1 / V, and YQ-D1 / V of the four channels respectively. This data is used for subsequent low-light fitting to eliminate the influence of low light and ensure calibration accuracy.

[0129] Fourth step: Set the temperature to 25℃, 50℃, and 75℃ respectively. Following the steps in the first, second, and third steps above, record the optical power meter readings and sampling voltages at each temperature and wavelength, denoted as XI-Pyx / dBm, XQ-Pyx / dBm, YI-Pyx / dBm, YQ-Pyx / dBm, XI-Myx / V, XQ-Myx / V, YI-Myx / V, YQ-Myx / V, XI-Dy / V, XQ-Dy / V, YI-Dy / V, YQ-Dy / V respectively. Here, y=1, 2, 3, and 4 correspond to -5℃, 25℃, 50℃, and 75℃ respectively. This completes all data acquisition.

[0130] The fifth step is low-light fitting. Taking the XI channel as an example, the MPD sampling voltages XI-D1, XI-D2, XI-D3, and XI-D4 at four temperatures (-5℃, 25℃, 50℃, and 75℃) are subjected to exponential fitting with temperature as the independent variable to obtain the coefficients a1 and the exponent b1. That is, the sampling voltage y1 corresponding to any temperature x1 (-5℃≤x1≤75℃) can be expressed as: y1=a1*e b1*x1 Similarly, the exponential fitting formulas for XQ, YI, and YQ (i.e., the dark light voltage calculation formula mentioned above) can be obtained, expressed as y2=a2*e b2 *x2 y3=a3*e b3*x3 y4=a4*e b4*x4 .

[0131] Step 6, taking the XI path at -5℃ and 191.3THz as an example, calculate the MPD responsivity (the ratio of photocurrent to incident light power) based on XI-P11, XI-M11, and XI-D1: Res_XI11=((XI-M11)-(XI-D1)) / 100 / (10 (XI -P11 / 10) ), the unit is uA / mW, where "10" in the formula (XI-P11 / 10) "This converts dBm to mW, and 100 represents the sampling resistor value in kΩ. Similarly, the responsivity of the four channels XI, XQ, YI, and YQ under all test temperatures and wavelengths can be calculated, denoted as Res_XIyx, Res_XQyx, Res_YIyx, and Res_YQyx, respectively. Here, x = 1, 2, 3, 4, 5, 6, 7 correspond to seven wavelengths: 191.3 THz, 192.2 THz, 192.95 THz, 193.85 THz, 194.6 THz, 195.5 THz, and 196.1 THz, respectively, and y = 1, 2, 3, 4 correspond to -5℃, 25℃, 50℃, and 75℃, respectively. This responsivity data is then compiled into a responsivity lookup table and stored in the coherent optical module. Thus, during actual operation of the coherent optical module, the responsivity under any operating temperature and wavelength condition can be calculated using the responsivity lookup table.

[0132] The following example illustrates the process of obtaining the target responsivity of each transmit optical path and controlling the transmit optical power during the operation of a coherent optical module. Assuming the coherent optical module operates at 30℃ and a wavelength of 193.7THz, the responsivity Res_XI_30℃_193.7THz of path XI can be obtained as follows:

[0133] 1) Since 25℃ < 30℃ < 50℃ and 192.95THz < 193.7THz < 193.85THz, based on 25℃, 50℃, 192.95THz, and 193.85THz, four corresponding responsivity values ​​can be obtained from the responsivity lookup table, namely Res_XI23, Res_XI24, Res_XI33, and Res_XI34;

[0134] 2) Based on the temperature dimension, perform linear interpolation to obtain the first reference responsivity Ref_Res_XI_30℃_192.95THz=Res_XI23+(30-25) / (50-25)*(Res_XI33-Res_XI 23) and the second reference responsivity Ref_Res_XI_30℃_193.85THz=Res_XI24+(30-25) / (50-25)*(Res_XI34-Res_XI24);

[0135] 3) Perform linear interpolation based on the wavelength dimension to obtain the final target responsivity Res_XI_30℃_193.7THz = Ref_Res_XI_30℃_192.95THz + (193.7 - 192.95) / (193.85 - 192.95) * (Ref_Res_XI_30℃_193.85THz - Ref_Res_XI_30℃_192.95THz).

[0136] The determination methods for the remaining operating temperature and wavelength conditions, as well as the target responsivity of the other three channels, are similar to the above process and will not be repeated here.

[0137] When controlling the transmitted optical power, taking the XI path as an example, assuming the coherent optical module operates at wavelengths of r℃ (-5≤r≤75) and sTHz (191.3≤s≤196.1), the target transmitted optical power of the XI path is tdBm, and the target responsivity is Res_XI_r℃_sTHz. Then, based on the dark light voltage calculation formula for the XI path, y1=a1*e b1*x1 The dark voltage corresponding to the XI path at r℃ can be obtained as a1*e b1*r The target sampling voltage XI-M-Target corresponding to the photodetector of the XI channel can be expressed as: XI-M-Target = Res_XI_r℃_sTHz * (10 (t / 10) )*100+a1*e b1*r 100 is the preset sampling resistor value, in kΩ.

[0138] After calculating the target sampling voltage XI-M-Target corresponding to the photodetector of path XI, the gain of the driver of path XI is adjusted based on the feedback between the current sampling voltage and the target sampling voltage of the photodetector of path XI, so that the current sampling voltage is consistent with the target sampling voltage. The transmit power control process of the other three paths is similar to that of path XI, and will not be described in detail here.

[0139] In one embodiment, step S201 specifically includes:

[0140] From the multiple operating temperatures and wavelengths recorded in the power error lookup table, determine the third and fourth operating temperatures corresponding to the current operating temperature of the coherent optical module, and the third and fourth operating wavelengths corresponding to the current operating wavelength of the coherent optical module. Then, obtain the first power error, the second power error, the third power error, and the fourth power error of the coherent optical module at the third operating temperature and third wavelength; the third and fourth operating temperatures are adjacent, and the current operating temperature is between the third and fourth operating temperatures. The third and fourth operating wavelengths are adjacent, and the current operating wavelength is between the third and fourth operating wavelengths. Based on the third operating temperature, the fourth operating temperature, the current operating temperature, the first power error, the second power error, the third power error, and the fourth power error, the first reference power error and the second reference power error of the coherent optical module at the current operating temperature and the third operating wavelength are calculated. Based on the third operating wavelength, the fourth operating wavelength, the current operating wavelength, the first reference power error, and the second reference power error, the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength is calculated.

[0141] In this embodiment, when the coherent optical module operates at a specific operating temperature and wavelength, the two operating temperatures closest to and adjacent to the current operating temperature of the coherent optical module, namely the third operating temperature and the fourth operating temperature, are first determined from multiple operating temperatures and wavelengths recorded in the power error lookup table; wherein the third operating temperature ≤ the current operating temperature ≤ the fourth operating temperature. Simultaneously, the two operating wavelengths closest to and adjacent to the current operating wavelength of the coherent optical module, namely the third operating wavelength and the fourth operating wavelength, are determined; wherein the third operating wavelength ≤ the current operating wavelength ≤ the fourth operating wavelength. Subsequently, the first power error of the coherent optical module under the third operating temperature and third operating wavelength conditions, the second power error under the third operating temperature and fourth operating wavelength conditions, the third power error under the fourth operating temperature and third operating wavelength conditions, and the fourth power error under the fourth operating temperature and fourth operating wavelength conditions are obtained.

[0142] After obtaining the first, second, third, and fourth power errors, linear interpolation along the temperature dimension is first performed on these errors to calculate the first reference power error and the second reference power error of the coherent optical module at the current operating temperature and third operating wavelength. Next, based on the obtained first and second reference power errors, linear interpolation along the wavelength dimension is performed to finally obtain the target received optical power error of the coherent optical module at the current operating temperature and current operating wavelength.

[0143] In one embodiment, the above-mentioned linear interpolation operation on the temperature dimension for the first power error, the second power error, the third power error, and the fourth power error may specifically include:

[0144] Calculate the third temperature difference between the current operating temperature and the third operating temperature, and the fourth temperature difference between the fourth operating temperature and the third operating temperature; calculate the third ratio of the third temperature difference to the fourth temperature difference; calculate the first power error difference between the third power error and the first power error; multiply the third ratio by the first power error difference and add it to the first power error to obtain the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength; calculate the second power error difference between the fourth power error and the second power error; multiply the third ratio by the second power error difference and add it to the second power error to obtain the second reference power error of the coherent optical module at the current operating temperature and the fourth operating wavelength.

[0145] In this embodiment, the third ratio represents the positional relationship between the current operating temperature and the third and fourth operating temperatures. A linear interpolation operation along the temperature dimension is performed using this third ratio, the first power error, and the third power error to obtain the first reference power error. This first reference power error can be understood as an estimated power error of the coherent optical module at the current operating temperature and the third operating wavelength. Similarly, a linear interpolation operation along the temperature dimension is performed using this third ratio, the second power error, and the fourth power error to obtain the second reference power error. This second reference power error can also be understood as an estimated power error of the coherent optical module at the current operating temperature and the fourth operating wavelength.

[0146] In one embodiment, based on the obtained first and second reference power errors, linear interpolation calculations are performed along the wavelength dimension, specifically including:

[0147] Calculate the third wavelength difference between the current operating wavelength and the third operating wavelength, and the fourth wavelength difference between the fourth operating wavelength and the third operating wavelength; calculate the fourth ratio of the third wavelength difference to the fourth wavelength difference; calculate the reference power error difference between the second reference power error and the first reference power error; multiply the fourth ratio by the reference power error difference and add it to the first reference power error to obtain the target received optical power error of the coherent optical module at the current operating temperature and current operating wavelength.

[0148] In this embodiment, the fourth ratio represents the positional relationship between the current operating wavelength and the third and fourth operating wavelengths. By combining the fourth ratio, the first reference power error, and the second reference power error, a linear interpolation operation is performed in the wavelength dimension to finally obtain the target received optical power error of the coherent optical module at the current operating temperature and current operating wavelength.

[0149] As can be seen, the coherent optical module optical power calibration method provided in this embodiment of the invention does not require testing all possible temperature and wavelength conditions to construct a power error lookup table for power calibration at the receiving end. It can select only a limited number of temperatures and wavelengths for testing. In actual coherent optical module receiving optical power calibration, the target receiving optical power error under any temperature and wavelength conditions can be obtained through two linear interpolation operations in the temperature and wavelength dimensions, effectively avoiding the production time consumption caused by intensive calibration of the entire temperature range and the entire wavelength range.

[0150] In one embodiment, step S203 specifically includes:

[0151] From the multiple gain control voltage averages recorded in the received optical power lookup table, determine the first and second average gain control voltages corresponding to the real-time gain control voltage average, and obtain the first received optical power corresponding to the first average gain control voltage and the second received optical power corresponding to the second average gain control voltage. The first and second average gain control voltages are adjacent, and the real-time gain control voltage average is between the first and second average gain control voltages. Calculate the first voltage difference between the real-time gain control voltage average and the first average gain control voltage, and the second voltage difference between the first and second average gain control voltages. Calculate the fifth ratio of the first voltage difference to the second voltage difference. Calculate the received optical power difference between the first and second received optical powers. Multiply the fifth ratio by the received optical power difference and add it to the first received optical power to obtain the reference received optical power corresponding to the real-time gain control voltage average.

[0152] In this embodiment, from the multiple average gain control voltage values ​​recorded in the received optical power lookup table, the two average gain control voltage values ​​that are closest to and adjacent to the average real-time gain control voltage value can be determined, namely the first average gain control voltage value and the second average gain control voltage value, wherein the first average gain control voltage value ≤ the average real-time gain control voltage value ≤ the second average gain control voltage value; then, the first received optical power corresponding to the first average gain control voltage value and the second received optical power corresponding to the second average gain control voltage value are obtained.

[0153] In this embodiment, the fifth ratio represents the positional relationship between the average real-time gain control voltage and the average first and second gain control voltages. By combining the fifth ratio, the first received optical power, and the second received optical power, a linear interpolation operation is performed to obtain the reference received optical power corresponding to the average real-time gain control voltage.

[0154] The following section provides a detailed explanation of the power error lookup table and the construction process of the received optical power lookup table involved in the receiver optical power calibration.

[0155] Continue to refer to Figure 2 For receiving optical power calibration, an external light source can be set to provide an optical signal. After the optical power is controlled by an adjustable optical attenuator, the signal is input to the receiving end of the coherent optical module. The input optical signal and the local oscillator light provided by ITLA are first mixed by a mixer (a 90° optical mixer is used in this embodiment), then converted into a current signal by a photodetector, and then converted into a voltage signal by a transimpedance amplifier. A received optical power lookup table is formed based on the correspondence between the average value of the four GC (Gain Control) voltages (RX_GC_XI, RX_GC_XQ, RX_GC_YI, RX_GC_YQ) output from the transimpedance amplifier and the received optical power of the coherent optical module. A power error lookup table is formed based on the received optical power errors of the coherent optical module at four temperatures (-5℃, 25℃, 50℃, 75℃) and seven wavelengths (191.3THz, 192.2THz, 192.95THz, 193.85THz, 194.6THz, 195.5THz, 196.1THz). During actual operation of the coherent optical module, the actual received optical power reported can be determined based on this received optical power lookup table and the power error lookup table. The specific process is as follows:

[0156] The first step involves adjusting the received optical power of the coherent optical module using an adjustable optical attenuator at a temperature of 25℃ and a wavelength of 193.85THz. The average values ​​of the four GC voltages (RX_GC_1, RX_GC_-3, ..., RX_GC_-27) are recorded when the received optical power is 1dBm, -1dBm, -3dBm, ..., -23dBm, -25dBm, -27dBm (note that the smaller the received optical power, the larger RX_GC). These 15 pairs of data are used as a reference to construct a received optical power lookup table. Under any operating temperature and wavelength conditions, the RX_GC acquired in real-time within the coherent optical module can linearly correspond to a reference received optical power (RX_POWER). For example, if the average real-time gain control voltage RX_GC_X collected by the coherent optical module at a certain moment is between RX_GC_-3 and RX_GC_-5, then using optical power values ​​of -3dBm and -5dBm for linear interpolation, the corresponding reference received optical power RX_POWER_X can be expressed as: RX_POWER_X = 10 * log 10 (10 (-3 / 10) +(RX_GC_X-RX_GC_-3) / (RX_GC_-3-RX_GC_-5)*((10 (-3 / 10) -(10 (-5 / 10) It is understandable that in the above formula, "10" means... (-3 / 10) +(RX_GC_X-RX_GC_-3) / (RX_GC_-3-RX_GC_-5)*((10 (-3 / 10) -(10 (-5 / 10) The result is a value in mW, then processed by "10*log 10 ()” is converted to a value in dBm.

[0157] The second step involves maintaining the actual received optical power of the coherent optical module at -11 dBm. The average value of the four GC voltages is recorded at four temperatures (-5℃, 25℃, 50℃, and 75℃) and seven wavelengths (191.3 THz, 192.2 THz, 192.95 THz, 193.85 THz, 194.6 THz, 195.5 THz, and 196.1 THz), denoted as RX_GC_yx. The reference received optical power, denoted as RX_POWER, is then obtained from the received optical power lookup table. _yx, where x = 1, 2, 3, 4, 5, 6, 7 correspond to seven wavelengths: 191.3THz, 192.2THz, 192.95THz, 193.85THz, 194.6THz, 195.5THz, and 196.1THz, respectively, and y = 1, 2, 3, 4 correspond to four temperatures: -5℃, 25℃, 50℃, and 75℃, respectively. The difference between RX_POWER_yx and -11dBm, RX_POWER_Err_yx, is filled into the power error lookup table. Thus, during actual operation of the coherent optical module, the received optical power error under any operating temperature and wavelength conditions can be calculated using the power error lookup table, thereby determining the final reported actual received optical power.

[0158] The following example illustrates the process of determining the reported actual received optical power during the operation of a coherent optical module. Assuming the coherent optical module operates at 30℃ and a wavelength of 193.7 THz, the corresponding target received optical power error can be obtained as follows:

[0159] 1) Since 25℃ < 30℃ < 50℃ and 192.95THz < 193.7THz < 193.85THz, based on 25℃, 50℃, 192.95THz, and 193.85THz, the corresponding four received optical power errors can be obtained from the power error lookup table, namely RX_POWER_Err_23, RX_POWER_Err_24, RX_POWER_Err_33, and RX_POWER_Err_34;

[0160] 2) Perform linear interpolation based on the temperature dimension to obtain the first reference power error Ref_RX_POWER_Err_30℃_192.95THz=RX_POWER_Err_23+(30-25) / (50-25)*(RX_POWER_Err_33-RX_POWER_Err_23) and the second reference power error Ref_RX_POWER_Err_30℃_193.85THz=RX_POWER_Err_24+(30-25) / (50-25)*(RX_POWER_Err_34-RX_POWER_Err_24);

[0161] 3) Perform linear interpolation based on the wavelength dimension to obtain the final target received optical power error RX_POWER_Err_30℃_193.7THz = Ref_RX_POWER_Err_30℃_192.95THz + (193.7-192.95) / (193.85-192.95)*(Ref_RX_POWER_Err_30℃_193.85THz-Ref_RX_POWER_Err_30℃_192.95THz).

[0162] Assuming the average real-time gain control voltage collected by the coherent optical module at a certain moment is RX_GC_X_30℃_193.7THz, the corresponding reference received optical power RX_POWER_30℃_193.7THz is obtained by looking up the received optical power lookup table and performing linear interpolation. Then, based on the reference received optical power RX_POWER_30℃_193.7THz and the target received optical power error RX_POWER_Err_30℃_193.7THz under the conditions of 30℃ and 193.7THz wavelength, the final determined actual received optical power RX_DDM_30℃_193.7THz can be expressed as: RX_DDM_30℃_193.7THz = RX_POWER_30℃_193.7THz - RX_POWER_Err_30℃_193.7THz.

[0163] To perform the corresponding steps in the above embodiments and various possible methods, one implementation of the coherent optical module optical power calibration device is given below. Please refer to... Figure 4 This is a functional block diagram of a coherent optical module optical power calibration device 400 provided in an embodiment of the present invention. It should be noted that the basic principle and technical effects of the coherent optical module optical power calibration device 400 provided in this embodiment are the same as those in the above embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the above embodiments. The coherent optical module optical power calibration device 400 includes a transmit optical power calibration module 410 and / or a receive optical power calibration module 420.

[0164] The transmit optical power calibration module 410 includes a responsivity acquisition unit 411, a dark light voltage acquisition unit 412, a target sampling voltage calculation unit 413, and a transmit optical power control unit 414.

[0165] The responsivity acquisition unit 411 is used to acquire the target responsivity of each transmission optical path of the coherent optical module under the current operating conditions according to the current operating conditions of the coherent optical module and the responsivity lookup table; the responsivity lookup table records the responsivity of each transmission optical path of the coherent optical module under different operating conditions.

[0166] It is understood that the response acquisition unit 411 can perform the above step S101.

[0167] The dark light voltage acquisition unit 412 is used to acquire the dark light voltage of each emitting optical path under the current operating conditions.

[0168] It is understood that the dark light voltage acquisition unit 412 can perform the above step S102.

[0169] The target sampling voltage calculation unit 413 is used to calculate the target sampling voltage corresponding to the photodetector of each transmitting optical path based on the target responsivity, dark light voltage and target value of the transmitted light power of each transmitting optical path.

[0170] It is understood that the target sampling voltage calculation unit 413 can perform the above step S103.

[0171] The transmit optical power control unit 414 is used to adjust the gain of the driver of each transmit optical path according to the current sampling voltage and the target sampling voltage of the photodetector of each transmit optical path, so that the current sampling voltage is consistent with the target sampling voltage.

[0172] It is understood that the transmit optical power control unit 414 can perform the above step S104.

[0173] Continue to refer to Figure 4 The received optical power calibration module 420 includes an optical power error acquisition unit 421, a voltage average acquisition unit 422, and a received optical power calculation unit 423.

[0174] The optical power error acquisition unit 421 is used to acquire the target received optical power error of the coherent optical module under the current operating conditions according to the current operating conditions of the coherent optical module and the power error lookup table; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions.

[0175] It is understood that the optical power error acquisition unit 421 can perform the above step S201.

[0176] The voltage average acquisition unit 422 is used to acquire the real-time gain control voltage average of each receiving optical path output by the transimpedance amplifier of the coherent optical module.

[0177] It is understood that the voltage average acquisition unit 422 can perform the above step S202.

[0178] The received optical power calculation unit 423 is used to obtain the reference received optical power corresponding to the average real-time gain control voltage based on the average real-time gain control voltage and the received optical power lookup table; the received optical power lookup table records the correspondence between the average gain control voltage and the received optical power under preset operating conditions; and the actual received optical power of the coherent optical module is obtained based on the reference received optical power and the received optical power error.

[0179] It is understood that the received optical power calculation unit 423 can perform the above steps S203 and S204.

[0180] Optionally, embodiments of the present invention also provide a coherent optical module, which includes a processor that executes a computer program to implement the optical power calibration method for the coherent optical module disclosed in the above embodiments.

[0181] Optionally, embodiments of the present invention also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the coherent optical module optical power calibration method disclosed in the above embodiments.

[0182] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0183] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0184] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0185] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the optical power of a coherent optical module, characterized in that, The coherent optical module optical power calibration method includes a received optical power calibration step; Alternatively, the coherent optical module optical power calibration method includes a transmit optical power calibration step and a receive optical power calibration step; The emitted optical power calibration step includes: Based on the current operating conditions of the coherent optical module and the responsivity lookup table, the target responsivity of each emission optical path of the coherent optical module under the current operating conditions is obtained; the responsivity lookup table records the responsivity of each emission optical path of the coherent optical module under different operating conditions. Obtain the dark light voltage of each of the aforementioned emission optical paths under the current operating conditions; Calculate the target sampling voltage corresponding to the photodetector of each of the aforementioned optical paths based on the target responsivity, dark light voltage, and target value of the emitted light power. The gain of the driver of each of the transmitting optical paths is adjusted according to the current sampling voltage and the target sampling voltage of the photodetector of each transmitting optical path, so that the current sampling voltage is consistent with the target sampling voltage; The received optical power calibration step includes: Based on the current operating conditions of the coherent optical module and the power error lookup table, the target received optical power error of the coherent optical module under the current operating conditions is obtained; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions. Obtain the average real-time gain control voltage of each receiving optical path output by the transimpedance amplifier of the coherent optical module; According to the real-time gain control voltage average value and the received optical power lookup table, the reference received optical power corresponding to the real-time gain control voltage average value is obtained; the received optical power lookup table records the correspondence between the gain control voltage average value and the received optical power under preset operating conditions. The actual received optical power of the coherent optical module is obtained based on the error between the reference received optical power and the received optical power.

2. The coherent optical module optical power calibration method according to claim 1, characterized in that, The operating conditions include operating temperature and operating wavelength; obtaining the target responsivity of each emission path of the coherent optical module under the current operating conditions based on the current operating conditions and a responsivity lookup table includes: The first and second operating temperatures corresponding to the current operating temperature of the coherent optical module, and the first and second operating wavelengths corresponding to the current operating wavelength of the coherent optical module, are determined from multiple operating temperatures and multiple operating wavelengths recorded in the responsivity lookup table. The first responsivity, the second responsivity, the third responsivity, and the fourth responsivity of each transmitting optical path at the first operating temperature and the first operating wavelength are obtained. The first and second operating temperatures are adjacent, and the current operating temperature is between the first and second operating temperatures. The first and second operating wavelengths are adjacent, and the current operating wavelength is between the first and second operating wavelengths. For each of the aforementioned optical transmission paths, based on the first operating temperature, the second operating temperature, the current operating temperature, the first responsivity, the second responsivity, the third responsivity, and the fourth responsivity corresponding to the optical transmission path, a first reference responsivity of the optical transmission path at the current operating temperature and the first operating wavelength, and a second reference responsivity at the current operating temperature and the second operating wavelength are calculated. Based on the first operating wavelength, the second operating wavelength, the current operating wavelength, the first reference responsivity, and the second reference responsivity, the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength is calculated.

3. The coherent optical module optical power calibration method according to claim 2, characterized in that, The step of calculating a first reference responsivity of the transmitting optical path at the current operating temperature and the first operating wavelength, and a second reference responsivity at the current operating temperature and the second operating wavelength, based on the first operating temperature, the second operating temperature, the current operating temperature, the first responsivity, the second responsivity, the third responsivity, and the fourth responsivity corresponding to the transmitting optical path, includes: Calculate the first temperature difference between the current operating temperature and the first operating temperature, and the second temperature difference between the second operating temperature and the first operating temperature; Calculate the first ratio of the first temperature difference to the second temperature difference; Calculate the first response difference between the third response and the first response; Multiply the first ratio by the first responsivity difference and add the result to the first responsivity to obtain the first reference responsivity of the emitted optical path at the current operating temperature and the first operating wavelength. Calculate the second response difference between the fourth response and the second response; Multiply the first ratio by the second responsivity difference and add it to the second responsivity to obtain the second reference responsivity of the emitted optical path at the current operating temperature and the second operating wavelength.

4. The coherent optical module optical power calibration method according to claim 2, characterized in that, The step of calculating the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength based on the first operating wavelength, the second operating wavelength, the current operating wavelength, the first reference responsivity, and the second reference responsivity includes: Calculate the first wavelength difference between the current operating wavelength and the first operating wavelength, and the second wavelength difference between the second operating wavelength and the first operating wavelength; Calculate the second ratio of the first wavelength difference to the second wavelength difference; Calculate the reference response difference between the second reference response and the first reference response; Multiply the second ratio by the difference between the reference responsivity and add it to the first reference responsivity to obtain the target responsivity of the emitted optical path at the current operating temperature and the current operating wavelength.

5. The method for calibrating the optical power of a coherent optical module according to claim 1, characterized in that, The calculation of the target sampling voltage corresponding to the photodetector of each of the emitted optical paths based on the target responsivity, dark light voltage, and target emitted light power of each emitted optical path includes: The theoretical sampling voltage is calculated based on the target responsivity of the transmitted optical path, the target value of the transmitted optical power, and the preset sampling resistor; the theoretical sampling voltage is the voltage generated by light. The theoretical sampling voltage is added to the dark light voltage to obtain the target sampling voltage corresponding to the photodetector in the emission optical path.

6. The method for calibrating the optical power of a coherent optical module according to claim 1, characterized in that, The operating conditions include operating temperature and operating wavelength; obtaining the target received optical power error of the coherent optical module under the current operating conditions based on the current operating conditions and power error lookup table includes: The third and fourth operating temperatures corresponding to the current operating temperature of the coherent optical module, and the third and fourth operating wavelengths corresponding to the current operating wavelength of the coherent optical module, are determined from multiple operating temperatures and multiple operating wavelengths recorded in the power error lookup table. The first power error, the second power error, the third power error, and the fourth power error of the coherent optical module at the third operating temperature and the third operating wavelength are obtained. The third and fourth operating temperatures are adjacent, and the current operating temperature is between the third and fourth operating temperatures. Similarly, the third and fourth operating wavelengths are adjacent, and the current operating wavelength is between the third and fourth operating wavelengths. Based on the third operating temperature, the fourth operating temperature, the current operating temperature, the first power error, the second power error, the third power error, and the fourth power error, calculate the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength, and the second reference power error at the current operating temperature and the fourth operating wavelength; Based on the third operating wavelength, the fourth operating wavelength, the current operating wavelength, the first reference power error, and the second reference power error, the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength is calculated.

7. The coherent optical module optical power calibration method according to claim 6, characterized in that, The calculation of the first reference power error and the second reference power error of the coherent optical module at the current operating temperature and the third operating wavelength, based on the third operating temperature, the fourth operating temperature, the current operating temperature, the first power error, the second power error, the third power error, and the fourth power error, includes: Calculate the third temperature difference between the current operating temperature and the third operating temperature, and the fourth temperature difference between the fourth operating temperature and the third operating temperature; Calculate the third ratio of the third temperature difference to the fourth temperature difference; Calculate the first power error difference between the third power error and the first power error; Multiplying the third ratio by the first power error difference and then adding it to the first power error yields the first reference power error of the coherent optical module at the current operating temperature and the third operating wavelength. Calculate the second power error difference between the fourth power error and the second power error; Multiplying the third ratio by the second power error difference and then adding it to the second power error yields the second reference power error of the coherent optical module at the current operating temperature and the fourth operating wavelength.

8. The method for calibrating the optical power of a coherent optical module according to claim 6, characterized in that, The calculation of the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength based on the third operating wavelength, the fourth operating wavelength, the current operating wavelength, the first reference power error, and the second reference power error includes: Calculate the third wavelength difference between the current operating wavelength and the third operating wavelength, and the fourth wavelength difference between the fourth operating wavelength and the third operating wavelength; Calculate the fourth ratio of the third wavelength difference to the fourth wavelength difference; Calculate the reference power error difference between the second reference power error and the first reference power error; Multiplying the fourth ratio by the difference in reference power error and then adding it to the first reference power error yields the target received optical power error of the coherent optical module at the current operating temperature and the current operating wavelength.

9. The method for calibrating the optical power of a coherent optical module according to claim 1, characterized in that, The step of obtaining the reference received optical power corresponding to the average real-time gain control voltage based on the lookup table of the average real-time gain control voltage and the received optical power includes: The first average gain control voltage and the second average gain control voltage corresponding to the real-time average gain control voltage are determined from multiple average gain control voltage values ​​recorded in the received optical power lookup table, and the first received optical power corresponding to the first average gain control voltage and the second received optical power corresponding to the second average gain control voltage are obtained; the first average gain control voltage and the second average gain control voltage are adjacent and the real-time average gain control voltage is between the first average gain control voltage and the second average gain control voltage; Calculate the first voltage difference between the average real-time gain control voltage and the average first gain control voltage, and the second voltage difference between the average first gain control voltage and the average second gain control voltage; Calculate the fifth ratio of the first voltage difference to the second voltage difference; Calculate the difference in received optical power between the first received optical power and the second received optical power; Multiplying the fifth ratio by the difference in received optical power and then adding it to the first received optical power yields the reference received optical power corresponding to the average real-time gain control voltage.

10. A coherent optical module optical power calibration device, characterized in that, The coherent optical module optical power calibration device includes a receiving optical power calibration module; or, the coherent optical module optical power calibration device includes a transmitting optical power calibration module and a receiving optical power calibration module. The transmitted optical power calibration module includes: The responsivity acquisition unit is used to acquire the target responsivity of each emission optical path of the coherent optical module under the current operating conditions based on the current operating conditions of the coherent optical module and a responsivity lookup table; the responsivity lookup table records the responsivity of each emission optical path of the coherent optical module under different operating conditions. A dark light voltage acquisition unit is used to acquire the dark light voltage of each of the emitted optical paths under the current operating conditions; The target sampling voltage calculation unit is used to calculate the target sampling voltage corresponding to the photodetector of each of the emission optical paths based on the target responsivity, dark light voltage and target value of emission light power of each of the emission optical paths; The transmit optical power control unit is used to adjust the gain of the driver of each transmit optical path according to the current sampling voltage and the target sampling voltage of the photodetector of each transmit optical path, so that the current sampling voltage is consistent with the target sampling voltage; The received optical power calibration module includes: The optical power error acquisition unit is used to acquire the target received optical power error of the coherent optical module under the current operating conditions based on the current operating conditions of the coherent optical module and a power error lookup table; the power error lookup table records the received optical power error of the coherent optical module under different operating conditions. The voltage average acquisition unit is used to acquire the real-time gain control voltage average of each receiving optical path output by the transimpedance amplifier of the coherent optical module. The received optical power calculation unit is used to obtain the reference received optical power corresponding to the average real-time gain control voltage according to the average real-time gain control voltage and the received optical power lookup table; the received optical power lookup table records the correspondence between the average gain control voltage and the received optical power under preset operating conditions; and obtain the actual received optical power of the coherent optical module according to the error between the reference received optical power and the received optical power.

11. A coherent optical module, characterized in that, The system includes a processor that executes a computer program to implement the steps of the coherent optical module optical power calibration method as described in any one of claims 1-9.

12. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the steps of the coherent optical module optical power calibration method as described in any one of claims 1-9.

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