Control method for solving abnormal temperature control of laser TEC

Abstract

The application solves the control method of abnormal TEC temperature control of laser, and the steps include: defining the controlled mode of laser temperature in the whole temperature working range of optical module: the ambient temperature is between-20°C and +60°C, the TEC is closed, and the laser temperature is in adaptive state; the ambient temperature is lower than-20°C, the TEC starts to heat the laser to keep warm, and the laser temperature is in controlled state; the ambient temperature is higher than +60°C, the TEC starts to cool the laser to control temperature, and the laser temperature is in controlled state; setting the trigger condition of TEC control action: introducing the temperature TMCU reported by the main chip of optical module as the software monitoring quantity, which is used as the total criterion of starting or stopping of TEC temperature control circuit; after determining the TEC trigger criterion, defining the controlled quantity TLD setting value: TEC start-stop decision: after starting the TEC, the laser temperature T LD Setting value decision.

Description

Technical Field

[0001] This invention relates to laser control technology, specifically, a control method for solving abnormal TEC (thermal control) of lasers. Background Technology

[0002] In M-band optical communication scenarios, 10G coarse wavelength division multiplexing (CWDM) optical modules are widely used. CWDM distributes all wavelengths in 20nm intervals, such as 1531nm, 1551nm, 1571nm, and 1591nm. To prevent interference between different center wavelengths during multiplexing and demultiplexing, which could lead to excessive insertion loss and transmission errors, the CWDM optical module technical specification requires that each wavelength of the CWDM series optical modules must have a temperature drift of <±6.5nm at its center wavelength across the entire temperature range.

[0003] Therefore, in engineering practice, the internal circuitry of coarse wavelength division multiplexing (CWDM) optical modules typically employs a TEC control circuit to regulate the laser temperature T. LD Control is performed based on the laser temperature T. LD The pattern of a 0.9~1nm shift in the center wavelength λ for every 10-degree change can be estimated by controlling the laser temperature T within the industrial ambient temperature range of -40 to 85°C. LD If the temperature is 25°C ± 40°C, the center wavelength temperature drift of the optical module can be < ± 4nm. This meets the technical specification requirement of < ± 6.5nm, while also allowing for engineering margins.

[0004] In practical engineering applications of laser temperature control, laser temperature control typically involves taking the laser temperature T as an example. LD As a method of direct negative feedback control of the monitored quantity, when the laser temperature T is monitored... LD When the temperature exceeds the threshold temperature, TEC control is activated to control the laser to cool or heat, causing the laser temperature to adjust in the opposite direction to approach the threshold temperature.

[0005] However, in engineering practice, it has been found that this negative feedback direct control method has a systematic defect: taking the controlled variable itself as the trigger condition will cause the trigger condition to cycle repeatedly between being met and not being met, which will lead to the TEC temperature control circuit repeatedly starting and stopping, and the total current Icc of the optical module repeatedly jumping, thus bringing the risk of temperature control circuit failure and the risk of repeated jumps in the total current and total power of the optical transmission equipment.

[0006] Meanwhile, because the TEC control circuit is repeatedly started and stopped, the laser temperature can only be controlled to change cyclically within a certain temperature range in this negative feedback direct control method, and it can never be stabilized within 1°C. Therefore, the quality of the emission eye diagram is also unstable, which brings data transmission risks.

[0007] Therefore, a control method for solving abnormal TEC temperature control in lasers is provided to address the above-mentioned problems. Summary of the Invention

[0008] The purpose of this invention is to provide a control method for solving abnormal TEC temperature control in lasers, thereby addressing the issue of laser temperature T... LD The negative feedback direct control method avoids the engineering risks associated with it; it avoids the circuit failure risk caused by repeated start-stop of the TEC temperature control circuit and the risk of repeated fluctuations in the total current and total power of the optical transmission equipment, as well as the data transmission risks caused by laser temperature instability and emission eye diagram instability. This ensures the stability of the CWDM optical module transmission equipment and the stability of data transmission.

[0009] The present invention achieves the above objectives through the following technical solutions: A control method for resolving abnormal TEC temperature control in lasers, comprising the following steps: 1) Define the controlled mode of laser temperature within the full operating temperature range of the optical module: With the ambient temperature between -20°C and +60°C, TEC is off, and the laser temperature is in an adaptive state. When the ambient temperature is below -20°C, the TEC (Transmission Control Unit) is activated to heat and maintain the temperature of the laser, keeping the laser temperature under control. When the ambient temperature is above +60°C, the TEC is activated to cool and control the laser temperature, and the laser temperature is under control. 2) Set the trigger conditions for TEC control actions: The temperature TMCU reported by the main chip of the optical module is introduced as a software monitoring quantity and serves as the overall criterion for starting or stopping the TEC temperature control circuit. 3) After the TEC trigger criterion is determined, define the TLD setting value of the controlled variable: After TEC starts, it first reads the laser temperature TLD to determine whether the TLD falls within the laser's operating temperature range, in order to distinguish whether the laser is in a full-temperature operating scenario or an extreme high and low temperature storage and startup scenario. 4) Decision regarding TEC start / stop: Host computer settings T MCU-H = +60°C, the lower-level machine detects when T MCU TEC starts at +60°C; Host computer settings T MCU-L = -10°C, the lower-level machine detects when T MCU < -10°C, TEC starts; 5) After TEC is started, the laser temperature T LD Determination of setting value: The host computer sets the laser operating temperature range T.LD-H = +65°C, T LD-L = -15°C; Lower-level computer detects laser temperature T LD If -15°C < T LD < +65°C will lock T LD Current temperature value.

[0010] Furthermore, the TMCU participates in the trigger decision and can provide real-time feedback on the internal temperature of the optical module, whose temperature changes are largely unaffected by the TEC control status.

[0011] Furthermore, the TMCU participates in the trigger decision, and the change trend of the TMCU is highly consistent with the change trend of the laser temperature TLD under the adaptive state, making it a highly reliable reference.

[0012] Furthermore, the TMCU's participation in triggering the laser temperature decision requires the intervention of controlled thresholds TLD-H and TLD-L, which have a flexible range of about 10 degrees, just enough to accommodate a temperature difference of about 5 to 10 degrees between the TMCU and the laser temperature TLD in the adaptive state.

[0013] Furthermore, in step 3), if the current temperature of the laser falls within the laser's operating temperature range, then the laser is determined to be operating in a full-temperature environment. The laser temperature TLD read back is then locked; while controlling the TLD, the laser temperature difference between the adaptive and controlled states of the TLD is minimized, thus achieving temperature control locking of the laser without temperature difference. Minimize the impact on the laser's operating state; The issue of setting the TLD (Total Temperature Limit) value of the laser in the high-temperature and low-temperature ranges under the full-temperature operating scenario of CWDM optical modules has been resolved.

[0014] Furthermore, in step 3), if the current temperature of the laser falls outside the laser's operating temperature range, then the laser is determined to be in an extreme high and low temperature storage startup scenario. By setting the laser temperature TLD to a fixed target value TLD-SET-H and TLD-SET-L, the TEC circuit is immediately activated when the laser temperature TLD is detected to be too high or too low during the extreme high and low temperature cold and hot start-up scenarios. This adjusts the laser temperature TLD to within the laser operating temperature range, preventing the laser temperature from being locked outside the laser operating temperature range and causing abnormal operation of the optical module. The issue of laser temperature TLD setting value under extreme high and low temperature storage startup scenarios of CWDM optical modules has been resolved.

[0015] Furthermore, in step 4), the lower-level machine detects the high-temperature cooling process, and T MCU When the temperature is below +50°C, TEC stops, and the lower-level machine has a built-in 10°C buffer. The lower-level machine detected the low-temperature heating process, and T MCU When the temperature is above 0°C, TEC stops, and the lower-level machine has a built-in 10°C buffer.

[0016] Furthermore, in step 5), the lower-level machine detects the laser temperature T. LD If T LD If the temperature is less than -15°C, then T will be set automatically. LD =-15°C, TEC starts heating up to bring the laser temperature T LD It rapidly approaches the -15°C setpoint; Lower-level computer detects laser temperature T LD If T LD If the temperature exceeds +65°C, then T will be automatically set. LD = +65°C, TEC starts cooling, bringing the laser temperature T LD It rapidly approaches the +65°C setting.

[0017] Compared with existing technologies, this invention eliminates the engineering risks associated with direct negative feedback control of laser temperature, while achieving stable laser temperature control that covers both full-temperature operating scenarios and high / low temperature storage power-on scenarios. It also provides more reliable wavelength drift control for CWDM optical modules; furthermore, it achieves low power consumption, energy efficiency, and reliability during normal operation, reducing the pressure on system power supply and heat dissipation. Attached Figure Description

[0018] Figure 1 This is the control logic diagram of the present invention. Detailed Implementation

[0019] Traditional CWDM optical modules employ a simple negative feedback direct control method in their internal laser temperature control software. The design concept is as follows: Take the laser temperature T... LD As a monitored quantity, the TLD is controlled to a fixed temperature point for temperature control design.

[0020] Software-defined laser high temperature threshold temperature T LD-H and laser cryogenic threshold temperature T LD-L During the module's operation, when T is detected... LD > T LD-H When this occurs, the TEC circuit is controlled to cool the laser. When T is detected... LD < T LD-L When the temperature is high, the TEC circuit is controlled to heat the laser. LD-L < TLD < T LD-H When T is in the off state, the TEC circuit is in the stopped state. LD The module adapts to the ambient temperature.

[0021] Examples of potential problems arising from negative feedback direct control methods: Let the high temperature threshold temperature T of the laser be... LD-H = +60°C, the equipment starts up and heats up.

[0022] After working for 5 minutes, T LD = +59°C, TEC circuit stops, ICC=140mA, ambient heat accumulates; After working for 6 minutes, T LD = +61°C, TEC circuit starts, ICC=180mA, ambient heat accumulates; After working for 7 minutes, T LD = +59°C, TEC circuit stops, ICC=140mA, ambient heat accumulates; Because the laser temperature T LD Above T LD-H and below T LD-H This cycle repeats itself, causing the module state to remain in a dead loop within steps 1-3 above. The TEC circuit repeatedly starts and stops, the laser temperature fluctuates unstablely between 59 and 61°C, and the total module current repeatedly jumps between 140mA and 180A. The laser emission eye diagram on the DCA repeatedly jumps with the start and stop of the TEC circuit (eye diagram baseline and eye diagram morphology jump), making it unstable. Most importantly, except for significant changes in ambient temperature, this abnormal state of repeated jumping cannot be corrected.

[0023] The root cause of these anomalies lies in the fact that traditional software algorithms use the laser temperature T... LD This simple negative feedback control method, where the trigger condition acts as both the control trigger and the controlled object, causes the trigger condition to cycle infinitely between being met and not met. This results in the TEC circuit repeatedly starting and stopping, leading to a series of anomalies and potential problems.

[0024] Example:

[0025] To address the aforementioned problems, this embodiment demonstrates a control method for resolving abnormal TEC temperature control in lasers, as detailed in the following document. Figure 1 The steps include: 1) Define the controlled mode of laser temperature within the full operating temperature range of the optical module: With the ambient temperature between -20°C and +60°C, TEC is off, and the laser temperature is in an adaptive state. When the ambient temperature is below -20°C, the TEC (Transmission Control Unit) is activated to heat and maintain the temperature of the laser, keeping the laser temperature under control. When the ambient temperature is above +60°C, the TEC is activated to cool and control the laser temperature, and the laser temperature is under control. 2) Set the trigger conditions for TEC control actions: The temperature TMCU reported by the main chip of the optical module is introduced as a software monitoring quantity and serves as the overall criterion for starting or stopping the TEC temperature control circuit. 3) After the TEC trigger criterion is determined, define the TLD setting value of the controlled variable: After TEC starts, it first reads the laser temperature TLD to determine whether the TLD falls within the laser's operating temperature range, in order to distinguish whether the laser is in a full-temperature operating scenario or an extreme high and low temperature storage startup scenario.

[0026] T MCU It participates in triggering the decision and can provide real-time feedback on the internal temperature of the optical module, and its temperature changes are basically unaffected by the TEC control status.

[0027] T MCU Participating in triggering the judgment, T MCU The changing trend of laser temperature T under adaptive state LD The trends are highly consistent and provide strong reference value.

[0028] T MCU The laser temperature involved in triggering the decision needs to be subject to a controlled threshold T. LD-H and T LD-L The design itself has about 10 degrees of flexibility, which is just enough to accommodate a T-shirt. MCU Laser temperature T under adaptive state LD The temperature difference is about 5 to 10 degrees.

[0029] In step 3), if the current temperature of the laser falls within the laser's operating temperature range, then the laser is determined to be operating in a full-temperature environment. The laser temperature T read back LD Immediately locked; after controlling T LD At the same time, it minimized T LD The temperature difference of the laser in adaptive and controlled states enables temperature control locking of the laser without temperature difference. Minimize the impact on the laser's operating state; Solved the problem of laser temperature T in both high-temperature and low-temperature ranges under the full-temperature operating scenario of CWDM optical modules. LD The issue is with setting values.

[0030] In step 3), if the current temperature of the laser falls outside the laser's operating temperature range, then the laser is determined to be in an extreme high and low temperature storage startup scenario. By setting the laser temperature TLD to a fixed target value TLD-SET-H and TLD-SET-L, the TEC circuit is immediately activated when the laser temperature TLD is detected to be too high or too low during the extreme high and low temperature cold and hot start-up scenarios. This adjusts the laser temperature TLD to within the laser operating temperature range, preventing the laser temperature from being locked outside the laser operating temperature range and causing abnormal operation of the optical module. The issue of laser temperature TLD setting value under extreme high and low temperature storage startup scenarios of CWDM optical modules has been resolved.

[0031] The decision-making mechanism and action logic for TEC start-stop: Host computer settings T MCU-H = +60°C, the lower-level machine detects when T MCU TEC starts at +60°C; Host computer settings T MCU-L = -10°C, the lower-level machine detects when T MCU < -10°C, TEC starts; The lower-level machine detected the high-temperature cooling process, and T MCU When the temperature is below +50°C, TEC stops, and the lower-level machine has a built-in 10°C buffer. The lower-level machine detected the low-temperature heating process, and T MCU When the temperature is above 0°C, TEC stops, and the lower-level machine has a built-in 10°C buffer. After TEC is started, the laser temperature T LD The decision-making mechanism and action logic for setting values: The host computer sets the laser operating temperature range T. LD-H = +65°C, T LD-L = -15°C; Lower-level computer detects laser temperature T LD If -15°C < T LD < +65°C will lock T LD Current temperature value; Lower-level computer detects laser temperature T LD If T LD If the temperature is less than -15°C, then T will be set automatically. LD = -15°C, TEC starts heating up to bring the laser temperature T LD It rapidly approaches the -15°C setpoint; Lower-level computer detects laser temperature T LD If TLD If the temperature exceeds +65°C, then T will be automatically set. LD = +65°C, TEC starts cooling, bringing the laser temperature T LD It rapidly approaches the +65°C setting.

[0032] Compared with existing technologies, this invention eliminates the engineering risks associated with direct negative feedback control of laser temperature, while achieving stable laser temperature control that covers both full-temperature operating scenarios and high / low temperature storage power-on scenarios. It also provides more reliable wavelength drift control for CWDM optical modules; furthermore, it achieves low power consumption, energy efficiency, and reliability during normal operation, reducing the pressure on system power supply and heat dissipation.

[0033] The above are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and all such modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A control method for resolving abnormal TEC temperature control in lasers, characterized by: steps include: 1) Define the controlled mode of laser temperature within the full operating temperature range of the optical module: With the ambient temperature between -20°C and +60°C, TEC is off, and the laser temperature is in an adaptive state. When the ambient temperature is below -20°C, the TEC (Transmission Control Unit) is activated to heat and maintain the temperature of the laser, keeping the laser temperature under control. When the ambient temperature is above +60°C, the TEC is activated to cool and control the laser temperature, and the laser temperature is under control. 2) Set the trigger conditions for TEC control actions: The temperature TMCU reported by the main chip of the optical module is introduced as a software monitoring quantity and serves as the overall criterion for starting or stopping the TEC temperature control circuit. 3) After the TEC trigger criterion is determined, define the TLD setting value of the controlled variable: After TEC starts, it first reads the laser temperature TLD to determine whether the TLD falls within the laser's operating temperature range, in order to distinguish whether the laser is in a full-temperature operating scenario or an extreme high and low temperature storage and startup scenario. 4) Decision regarding TEC start / stop: Host computer settings T MCU-H = +60°C, the lower-level machine detects when T MCU TEC starts at +60°C; Host computer settings T MCU-L = -10°C, the lower-level machine detects when T MCU < -10°C, TEC starts; 5) After TEC is started, the laser temperature T LD Determination of setting value: The host computer sets the laser operating temperature range T. LD-H = +65°C, T LD-L = -15°C; Lower-level computer detects laser temperature T LD If -15°C < T LD < +65°C will lock T LD Current temperature value.

2. The control method for solving abnormal TEC temperature control in lasers according to claim 1, characterized in that: The TMCU participates in the trigger decision and can provide real-time feedback on the internal temperature of the optical module. Its temperature changes are basically unaffected by the TEC control status.

3. The control method for solving abnormal TEC temperature control in lasers according to claim 1, characterized in that: TMCU participates in the trigger decision, and the trend of TMCU change is highly consistent with the trend of laser temperature TLD change in adaptive state, which is highly reliable.

4. The control method for solving abnormal TEC temperature control in lasers according to claim 1, characterized in that: The TMCU's participation in triggering the laser temperature decision requires the intervention of controlled thresholds TLD-H and TLD-L. The settings themselves have a flexibility of about 10 degrees, which can just accommodate a temperature difference of about 5 to 10 degrees between the TMCU and the laser temperature TLD in the adaptive state.

5. A control method for solving abnormal TEC temperature control in lasers according to any one of claims 1-4, characterized in that: In step 3), if the current temperature of the laser falls within the laser's operating temperature range, then the laser is determined to be operating in a full-temperature environment. The laser temperature TLD read back is then locked; while controlling the TLD, the laser temperature difference between the adaptive and controlled states of the TLD is minimized, thus achieving temperature control locking of the laser without temperature difference. Minimize the impact on the laser's operating state; The issue of setting the TLD (Total Temperature Limit) value of the laser in the high-temperature and low-temperature ranges under the full-temperature operating scenario of CWDM optical modules has been resolved.

6. The control method for solving abnormal TEC temperature control in lasers according to claim 5, characterized in that: In step 3), if the current temperature of the laser falls outside the laser's operating temperature range, then the laser is determined to be in an extreme high and low temperature storage startup scenario. By setting the laser temperature TLD to a fixed target value TLD-SET-H and TLD-SET-L, the TEC circuit is immediately activated when the laser temperature TLD is detected to be too high or too low during the extreme high and low temperature cold and hot start-up scenarios. This adjusts the laser temperature TLD to within the laser operating temperature range, preventing the laser temperature from being locked outside the laser operating temperature range and causing abnormal operation of the optical module. The issue of laser temperature TLD setting value under extreme high and low temperature storage startup scenarios of CWDM optical modules has been resolved.

7. A control method for solving abnormal TEC temperature control in lasers according to claim 6, characterized in that: In step 4), the lower-level machine detects the high-temperature cooling process, and T MCU When the temperature is below +50°C, TEC stops, and the lower-level machine has a built-in 10°C buffer. The lower-level machine detected the low-temperature heating process, and T MCU When the temperature is above 0°C, TEC stops, and the lower-level machine has a built-in 10°C buffer.

8. A control method for solving abnormal TEC temperature control in lasers according to claim 7, characterized in that: In step 5), the lower-level machine detects the laser temperature T. LD If T LD If the temperature is less than -15°C, then T will be set automatically. LD = -15°C, TEC starts heating up to bring the laser temperature T LD It rapidly approaches the -15°C setpoint; Lower-level computer detects laser temperature T LD If T LD If the temperature exceeds +65°C, then T will be automatically set. LD = +65°C, TEC starts cooling, bringing the laser temperature T LD It rapidly approaches the +65°C setpoint.

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