Optical wavelength adjustable communication module based on temperature control tuning

Abstract

The invention discloses an optical wavelength-adjustable communication module based on temperature control tuning, which belongs to the technical field of optical communication and comprises a main control unit, a laser driving module, a semiconductor refrigeration module, a laser and a modulation signal unit. The main control unit is electrically connected with the laser driving module and the semiconductor refrigeration module and is used for outputting a control instruction and receiving state feedback; the laser driving module is electrically connected with the laser and used for driving the laser to a specified light-emitting state; the semiconductor refrigeration module is thermally coupled with the laser and used for accurately regulating the working temperature of the laser; and the modulation signal unit loads the radio frequency modulation signal to the laser to realize optical signal transmission.

Description

TECHNICAL FIELD

[0001] The application relates to a tunable optical wavelength communication module based on temperature control tuning, and belongs to the technical field of optical communication. BACKGROUND

[0002] At present, with the rapid development of optical communication technology, the performance of a tunable optical wavelength communication module, which is a core component in an optical fiber communication network, a data center interconnection and an optical sensing system, directly determines the transmission capacity, rate and reliability of a communication system. With the wide application of 5G communication, cloud computing and big data technology, the demand for bandwidth of a communication network increases exponentially, which requires the communication module to have flexible and adjustable wavelength characteristics to realize wavelength multiplexing, dynamic channel allocation and rapid fault repair, and therefore, tunable optical wavelength technology has become a key means to improve the resource utilization rate of a communication system.

[0003] The tuning methods of the existing tunable optical wavelength communication module mainly include mechanical tuning, electrical tuning and temperature control tuning. The mechanical tuning adjusts the wavelength by changing the physical position of an optical element, but has defects such as slow response speed (usually greater than 100 ms), complex structure and being easily affected by vibration, and is difficult to meet the needs of high-speed dynamic communication scenarios. The electrical tuning adjusts the wavelength by using the electro-optic effect of a semiconductor material, and has problems such as narrow tuning range (usually less than 3 nm) and wavelength stability being significantly affected by voltage fluctuations, and is prone to performance drift after long-term use.

[0004] Temperature control tuning has become one of the mainstream technologies due to its simple structure and wide tuning range, but still has many technical bottlenecks in practical application. Firstly, the temperature control precision is insufficient. Traditional temperature control modules mostly use ordinary temperature sensors and analog control circuits, and the temperature detection precision can only reach ±0.1℃, resulting in poor wavelength stability of a laser output (usually greater than ±0.5nm), which cannot meet the channel isolation requirements of a high-density wavelength division multiplexing system. Secondly, the thermal coupling efficiency is low. The connection between the existing TEC and the laser mostly adopts the pasting method of heat-conducting glue, and the thermal resistance is generally greater than 1℃ / W, which causes serious heat conduction lag, and the wavelength tuning response time is too long (more than 20 ms), affecting the dynamic channel adjustment efficiency. Thirdly, there is a lack of effective wavelength feedback calibration mechanism. Under the conditions of environmental temperature change or long-term work, the laser wavelength is prone to cumulative deviation, and needs to be calibrated manually regularly, which is high in maintenance cost. Fourthly, the stability of the laser drive circuit is insufficient. The fluctuation of the drive current easily leads to unstable output power, and further introduces communication signal noise. Fifthly, the tuning step cannot meet the high-precision demand. The minimum adjustment step of most existing modules is greater than 0.1nm, which is difficult to realize fine channel division. SUMMARY

[0005] The application aims to provide a tunable optical wavelength communication module based on temperature control tuning to solve the problems in the background technology.

[0006] In order to achieve the above object, the present application adopts the following technical solutions:

[0007] Compared with the prior art, the present application provides a design of a tunable wavelength communication module based on temperature control tuning, which comprises a main control unit, a laser driver module, a semiconductor refrigeration module, a laser and a modulation signal unit. The main control unit is electrically connected with the laser driver module and the semiconductor refrigeration module respectively, and is used for outputting control instructions and receiving state feedback. The laser driver module is electrically connected with the laser, and is used for driving the laser to a specified light-emitting state. The semiconductor refrigeration module is thermally coupled with the laser, and is used for accurately regulating the working temperature of the laser. The modulation signal unit loads a radio frequency modulation signal to the laser to realize optical signal transmission.

[0008] Through the above technical solutions, the main control unit as the core control component outputs control instructions and sends them to the laser driver module and the semiconductor refrigeration module respectively, and simultaneously receives the working state information fed back by the two modules. The laser driver module is controlled by the main control unit to drive the laser to enter a specified light-emitting state. The semiconductor refrigeration module forms a thermal coupling relationship with the laser, and can accurately regulate the working temperature of the laser. The modulation signal unit loads a radio frequency modulation signal to the laser, so that the laser outputs an optical signal carrying information, thereby realizing the transmission of the optical signal.

[0009] The units cooperate with each other to build a complete working system of the tunable wavelength communication module based on temperature control tuning, which not only realizes the effective transmission of the optical signal, but also lays a foundation for the subsequent accurate tuning of the wavelength, and guarantees the basic function realization of the communication module.

[0010] Further, the semiconductor refrigeration module comprises a semiconductor temperature control device TEC and a temperature control module. The semiconductor temperature control device TEC is directly thermally coupled with the laser, and the temperature control module is electrically connected with the semiconductor temperature control device TEC and the main control unit respectively, and is used for receiving the target temperature instruction of the main control unit and driving the semiconductor temperature control device TEC to adjust the temperature of the laser, so as to realize the tuning of the output wavelength of the laser through the temperature change.

[0011] Through the above technical solutions, after the temperature control module in the semiconductor refrigeration module receives the target temperature instruction sent by the main control unit, it drives the semiconductor temperature control device TEC directly thermally coupled with the laser to work. The temperature of the laser is adjusted through the temperature change of the semiconductor temperature control device TEC, and then the tuning of the output wavelength of the laser is realized by utilizing the characteristic of the temperature change of the laser.

[0012] The internal structure and working process of the semiconductor refrigeration module are determined, the temperature regulation is used to realize the controllable tuning of the laser output wavelength, the accuracy and reliability of the wavelength tuning are improved, and the communication quality of the communication module is improved.

[0013] Further, the semiconductor temperature control device TEC and the laser are directly bonded by eutectic welding or thermal compression welding; the eutectic welding uses gold-tin solder, the bonding layer has a thickness of 5-10 μm, and the thermal resistance is ≤0.5 ℃ / W.

[0014] By the above technical solution, the semiconductor temperature control device TEC and the laser are directly bonded by eutectic welding or thermal compression welding, gold-tin solder is used in the eutectic welding process, the bonding layer has a thickness of 5-10 μm, and the thermal resistance between the two is ≤0.5 ℃ / W, so as to ensure good heat conduction effect between the TEC and the laser.

[0015] By the optimized bonding mode and precise parameter control, efficient thermal coupling between the TEC and the laser is realized, the thermal resistance is greatly reduced, the response speed of temperature regulation is accelerated, and the temperature regulation accuracy is improved, thereby providing a solid heat conduction guarantee for accurate tuning of the laser wavelength.

[0016] Further, the temperature control module integrates a high-precision temperature sensor and a PID control circuit; the temperature sensor is a PT100 or NTC thermistor, and the temperature detection accuracy is ≤0.01 ℃; the PID control circuit is realized by a 32-bit MCU, the temperature control accuracy is ±0.1 ℃, and the corresponding laser output wavelength stability is ±0.1 nm.

[0017] By the above technical solution, the high-precision temperature sensor integrated in the temperature control module is a PT100 or NTC thermistor, which detects the temperature of the laser in real time, and the temperature detection accuracy is ≤0.01 ℃; the PID control circuit realized by the 32-bit MCU compares and analyzes the detected temperature and the target temperature, and regulates the semiconductor temperature control device TEC, so that the temperature control accuracy is ±0.1 ℃, thereby ensuring that the laser output wavelength stability is ±0.1 nm.

[0018] The high-precision temperature sensor and the advanced PID control circuit are used to realize high-precision control of the temperature of the laser, significantly improve the stability of the laser output wavelength, reduce the influence of wavelength fluctuation on communication, and improve the communication quality and reliability of the communication module.

[0019] Further, the wavelength feedback calibration system comprises a standard filter and a photoelectric detector; the standard filter receives the laser output optical signal, and the photoelectric detector converts the filtered optical signal into an electrical signal and feeds it back to the main control unit for correcting the temperature control parameters.

[0020] Through the technical scheme, the etalon filter in the wavelength feedback calibration system receives the optical signal output by the laser and performs filtering processing, the photodetector converts the filtered optical signal into an electrical signal, and then feeds back the electrical signal to the master control unit, and the master control unit corrects the temperature control parameter according to the feedback signal to optimize the output wavelength of the laser.

[0021] Through the real-time monitoring and feedback correction mechanism of the wavelength feedback calibration system, the deviation that may occur in the temperature regulation process is effectively compensated, the tuning accuracy and long-term stability of the output wavelength of the laser are further improved, and the anti-interference ability of the communication module is enhanced.

[0022] Further, the semiconductor temperature control device TEC is a micro-TEC with a size of 2mm*2mm-5mm*5mm, a working voltage of 3-5V, and a maximum refrigeration power of ≥2W; the laser is a DFB laser or a DBR laser, and the temperature sensitivity of the output wavelength is 0.1nm / ℃, the working temperature range is 10-50℃, and the corresponding wavelength tuning range is ≥5nm.

[0023] Through the technical scheme, the micro-TEC with a size of 2mm*2mm-5mm*5mm, a working voltage of 3-5V, and a maximum refrigeration power of ≥2W provides temperature regulation for the laser (DFB laser or DBR laser); since the temperature sensitivity of the output wavelength of the laser is 0.1nm / ℃, within the working temperature range of 10-50℃, a wavelength tuning range of ≥5nm can be achieved.

[0024] The specific parameter range of the TEC and the laser is specified to ensure the matching and cooperative working ability of the two in performance, to ensure that the communication module can work stably within a wide wavelength tuning range, and to meet the diversified demand for wavelength in different communication scenarios.

[0025] Further, the laser drive module includes a constant current source circuit and a state monitoring circuit; the constant current source circuit outputs a stable driving current of 50-200mA to control the output power of the laser; and the state monitoring circuit collects the working current, voltage and junction temperature signals of the laser in real time and feeds them back to the master control unit.

[0026] Through the technical scheme, the constant current source circuit of the laser drive module outputs a stable driving current of 50-200mA to control the output power of the laser; and the state monitoring circuit collects the working current, voltage and junction temperature signals of the laser in real time and feeds them back to the master control unit, providing a basis for the regulation of the master control unit.

[0027] The constant current source circuit ensures the stability of the laser output power, and avoids the influence of power fluctuation on the communication signal; and the state monitoring circuit realizes real-time monitoring of the working state of the laser, so that the main control unit can timely discover and handle abnormal conditions, and the reliability and safety of the communication module are improved.

[0028] Further, the modulation signal unit supports direct modulation of radio frequency signals, the modulation frequency range is 100MHz-10GHz, and the modulation depth is greater than or equal to 90%; the wavelength tuning response time is less than or equal to 5ms, and continuous wavelength interval adjustment is supported, and the minimum adjustment step is less than or equal to 0.05nm.

[0029] Through the above technical scheme, the modulation signal unit supports direct modulation of radio frequency signals in the frequency range of 100MHz-10GHz, and the modulation depth is greater than or equal to 90%; at the same time, the wavelength tuning response time of the module is less than or equal to 5ms, and continuous wavelength interval adjustment is supported, and the minimum adjustment step is less than or equal to 0.05nm, which can quickly and accurately realize wavelength adjustment.

[0030] The wide modulation frequency range and high modulation depth improve the modulation performance of the optical signal, ensuring the quality and efficiency of signal transmission; the fast wavelength tuning response time and small adjustment step enhance the flexibility and accuracy of wavelength adjustment, so that the communication module can better adapt to different communication demands and environmental changes.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] Excellent tuning performance: response time less than or equal to 5ms, wavelength adjustment step less than or equal to 0.05nm, supporting continuous wavelength coverage greater than or equal to 5nm, temperature in the range of 10-50℃, meeting the dynamic optical network reconstruction requirements;

[0033] High precision and stability: temperature control precision ±0.1℃, corresponding wavelength stability ±0.1nm, time length 24 hours, short-term precision after feedback calibration by etalon reaches ±0.02nm, suitable for DWDM system;

[0034] High reliability: no mechanical moving parts, semiconductor temperature control device TEC and laser eutectic welding bonding reliability >1000 times of thermal cycle, temperature in the range of -40℃ to +85℃, MTBF >100,000 hours;

[0035] High integration: COB packaging is adopted, and the module size is less than or equal to 10mm*10mm*3mm, which is 40% smaller than the volume of the traditional external temperature control scheme;

[0036] Significant cost advantage: based on mature semiconductor temperature control device TEC and DFB laser process, batch production cost is reduced compared with MEMS tuning scheme and current tuning scheme;

[0037] Good compatibility: support 100MHz-10GHz RF direct modulation, can directly replace the traditional fixed wavelength optical module, without modifying the existing transmission system. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, brief descriptions will be given below of the drawings needed in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained according to the structures shown in the drawings without creative labor for those skilled in the art.

[0039] Fig. 1 The module structure of the present application is shown in the figure.

[0040] Fig. 2 The wavelength characteristic curve of the present application is shown in the figure.

[0041] Fig. 3 The wavelength tuning control flowchart of the present application is shown in the figure. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0043] Please refer to Figs. 1-3 The present application provides a technical solution:

[0044] A tunable optical wavelength communication module based on temperature control tuning, comprising a master control unit, which adopts an ARM Cortex-M4 architecture 32-bit MCU, with a main frequency ≥ 80MHz, and a built-in temperature and wavelength mapping table with a precision of 0.01℃ / 0.001nm; through an I 2 C or SPI interface, it communicates with the laser driver module and the temperature control module, realizes instruction issuing and data acquisition; supports the host computer to send target wavelength instruction resolution 0.01nm through RS232 or Ethernet interface.

[0045] The laser driver module includes a constant current source submodule and a monitoring submodule: the constant current source adopts a low dropout linear regulator LDO design, with an output current of 50-200mA continuously adjustable, and a current ripple ≤10μA; the monitoring submodule integrates a current sensor with a precision of ±1mA, a voltage sensor with a precision of ±5mV, and a junction temperature sampling circuit, which feeds back the laser working state to the master control unit in real time.

[0046] Semiconductor refrigeration module, semiconductor temperature control device TEC: select bismuth telluride-based micro-TEC, size 3mm*3mm*0.5mm, temperature difference range-40℃ to +85℃, maximum refrigeration power 2.5W@25℃, thermal response time≤2ms;

[0047] The temperature control module is composed of PT100 temperature sensor, measurement range-50℃ to +150℃, accuracy ±0.01℃, PID control circuit; the PID parameters are dynamically optimized by the main control unit, the temperature control accuracy is ±0.1℃, and the regulation bandwidth is ≥1kHz.

[0048] The laser adopts InP-based distributed feedback DFB laser or distributed Bragg reflection DBR laser, the working wavelength range is 1525-1565nm, the C band, the threshold current is ≤20mA, the output power is ≥10mW; the wavelength temperature sensitivity is 0.1nm / ℃, the single-mode output, and the side mode suppression ratio SMSR is ≥40dB.

[0049] Wavelength feedback calibration system, integrated standard filter, free spectral range 100GHz, transmission peak half-width≤0.1nm, with high-sensitivity photodetector, responsivity≥0.8A / W@1550nm; the laser output light is incident to the standard filter after 10% light splitting, the detector converts the transmitted light intensity signal into an electric signal, the signal-to-noise ratio is ≥50dB, and the electric signal is fed back to the main control unit for wavelength deviation correction, and the correction accuracy is ±0.02nm.

[0050] Modulation signal unit, adopts a direct modulation mode, and the radio frequency signal 100MHz-10GHz is loaded to the positive electrode of the laser through an impedance matching circuit 50Ω, the modulation bandwidth is ≥10GHz, the extinction ratio is ≥8dB, and the eye diagram jitter is ≤5ps.

[0051] The present application realizes accurate wavelength tuning through closed-loop temperature control, and the specific process is as follows:

[0052] Initialization: after the main control unit is powered on, the pre-stored temperature-wavelength mapping table is read, the laser driver module starts the laser to the initial light-emitting state, 25℃, 1550nm;

[0053] Instruction receiving: the main control unit receives the target wavelength instruction of the upper computer, such as 1551.2nm, calculates the corresponding target temperature through table lookup, 25℃+(1551.2-1550) / 0.1=37℃;

[0054] Temperature adjustment: the main control unit sends the target temperature 37℃ to the temperature control module, the temperature control module drives the TEC to adjust the temperature of the laser through heat conduction, and the PT100 collects the junction temperature of the laser in real time and feeds back;

[0055] Wavelength calibration: standard filter detects the wavelength of laser output light, photodetector outputs light intensity signal to the host unit, calculates the deviation of actual wavelength and target wavelength, such as deviation +0.03nm;

[0056] Closed-loop correction: the host unit adjusts the target temperature according to the deviation, and the temperature control module adjusts the TEC again until the actual wavelength is stable within the target value ±0.1nm, and the target temperature is 37℃+0.03 / 0.1=37.3℃;

[0057] State maintenance: the host unit continuously monitors the laser temperature, current, power and wavelength deviation, dynamically corrects the temperature control amount every 10ms, and ensures long-term stability.

[0058] In this embodiment, the C-band DFB laser temperature control and tuning module,

[0059] Laser selection: InP-based DFB laser, model XXX-DFB-1550, 25℃ center wavelength 1550.0557nm, threshold current 15mA, output power 15mW, SMSR 45dB;

[0060] TEC selection: 3mm×3mm Bi2Te3-based TEC, model XXX-TEC-3305, working voltage 3.3V, maximum current 1.5A, thermal resistance 0.4℃ / W;

[0061] Bonding process: gold-tin eutectic bonding, bonding temperature 300℃, pressure 50g, bonding layer thickness 8μm, thermal resistance test value 0.35℃ / W;

[0062] Temperature control system: PT100 sensor is attached to the laser substrate, 32-bit MCU realizes PID control, proportional coefficient Kp=5.0, integral coefficient Ki=0.1, differential coefficient Kd=0.05;

[0063] Wavelength feedback: standard free spectral range 100GHz, detector responsivity 0.85A / W, feedback sampling frequency 1kHz;

[0064] Performance test results:

[0065] Tuning range: 1548-1553nm, corresponding temperature 5℃-45℃;

[0066] Tuning response time: 3.2ms, from 1550nm to 1553nm;

[0067] Wavelength stability: ±0.05nm, 24 hours, temperature fluctuation ±2℃;

[0068] Modulation performance: 10GHz signal modulation, eye diagram extinction ratio 8.5dB, jitter 4.2ps;

[0069] Environmental adaptability: after high and low temperature test of -40℃ to +85℃, the performance index has no obvious drift.

[0070] As shown in the temperature-wavelength characteristic curve diagram. Fig. 2

[0071] When the temperature is 10℃, the wavelength is 1548.39;

[0072] When the temperature is 15℃, the wavelength is 1548.96;

[0073] When the temperature is 20℃, the wavelength is 1549.50;

[0074] When the temperature is 25℃, the wavelength is 1550.06;

[0075] When the temperature is 30℃, the wavelength is 1550.61;

[0076] When the temperature is 35℃, the wavelength is 1551.17;

[0077] When the temperature is 40℃, the wavelength is 1551.72;

[0078] When the temperature is 45℃, the wavelength is 1552.28;

[0079] When the temperature is 50℃, the wavelength is 1552.83.

[0080] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of the present application being defined by the appended claims and their equivalents.​

Claims

1. A communication module with tunable optical wavelength based on temperature control tuning, characterized in that, include: The system comprises a main control unit, a laser driver module, a semiconductor cooling module, a laser, and a modulation signal unit. The main control unit is electrically connected to both the laser driver module and the semiconductor cooling module, and is used to output control commands and receive status feedback. The laser driver module is electrically connected to the laser and is used to drive the laser to a specified emission state. The semiconductor cooling module is thermally coupled to the laser and is used to precisely control the laser's operating temperature. The modulation signal unit loads an radio frequency modulation signal onto the laser to achieve optical signal transmission.

2. The communication module according to claim 1, characterized in that, The semiconductor cooling module includes a semiconductor temperature controller (TEC) and a temperature control module. The TEC is directly thermally coupled to the laser. The temperature control module is electrically connected to the TEC and the main control unit, respectively, and is used to receive the target temperature command from the main control unit and drive the TEC to adjust the laser temperature, thereby achieving the tuning of the laser output wavelength through temperature changes.

3. The communication module according to claim 2, characterized in that, The semiconductor temperature control device (TEC) and the laser are directly bonded by eutectic bonding or thermostatic bonding; the eutectic bonding uses gold-tin solder, the bonding layer thickness is 5-10 μm, and the thermal resistance is ≤0.5℃ / W.

4. The communication module according to claim 1, characterized in that, The temperature control module integrates a high-precision temperature sensor and a PID control circuit; the temperature sensor is a PT100 or NTC thermistor with a temperature detection accuracy of ≤0.01℃; the PID control circuit is implemented through a 32-bit MCU, achieving a temperature control accuracy of ±0.1℃, corresponding to a laser output wavelength stability of ±0.1nm.

5. The communication module according to claim 1, characterized in that, It also includes a wavelength feedback calibration system, which consists of an etalon filter and a photodetector; the etalon filter receives the optical signal output by the laser, and the photodetector converts the filtered optical signal into an electrical signal and feeds it back to the main control unit for correcting the temperature control parameters.

6. The communication module according to claim 2, characterized in that, The semiconductor temperature control device (TEC) is a miniature TEC with dimensions of 2mm×2mm-5mm×5mm, an operating voltage of 3-5V, and a maximum cooling power of ≥2W; the laser is a DFB laser or a DBR laser with a temperature sensitivity of 0.1nm / ℃ for its output wavelength, an operating temperature range of 10-50℃, and a corresponding wavelength tuning range of ≥5nm.

7. The communication module according to claim 1, characterized in that, The laser driving module includes a constant current source circuit and a status monitoring circuit; the constant current source circuit outputs a stable driving current of 50-200mA to control the laser output power; the status monitoring circuit collects the laser's operating current, voltage, and junction temperature signals in real time and feeds them back to the main control unit.

8. The communication module according to claim 1, characterized in that, The modulation signal unit supports direct modulation of radio frequency signals, with a modulation frequency range of 100MHz-10GHz and a modulation depth of ≥90%; the wavelength tuning response time is ≤5ms, and it supports continuous wavelength interval adjustment with a minimum adjustment step size of ≤0.05nm.

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