High accuracy temperature control system of DBR laser based on ADN8834

For the extremely weak magnetic field measurement of atomic magnetometers, the precise and stable control of laser temperature is an essential work. Laser temperature instability can lead to laser wavelength fluctuations and drift, thus reducing the sensitivity of atomic magnetometers. In order to reduce the influence of laser temperature fluctuation on atomic magnetometer, a high precision DBR laser automatic temperature control system based on ADN8834 temperature control chip is designed and implemented. Firstly, a temperature feedback circuit is designed based on ADN8834 and a high precise A/D converter chip LTC2377, so that the analog voltage signal corresponding to the temperature is successfully collected and converted into a digital signal and sent to the FPGA. Then, the incremental digital PID algorithm is implemented in FPGA to automatically calculate the temperature control signal. Then, a D/A converter circuit is designed to convert the temperature control signal into an analog signal and transmit it to ADN8834. Finally, ADN8834 outputs heating or cooling signals to control the semiconductor thermoelectric cooler, so as to realize closed-loop temperature automatic control. The experimental results show that the temperature stability of the automatic temperature control system is +/- 0. 005 degrees C when the target temperature is set at 20, 25, 30 degrees C, and the stability of output wavelength is +/- 2 pm. This DBR laser automatic temperature control system has high temperature stability, convenient operation and flexible design, and basically meets the requirements of atomic magnetometer system for laser temperature control.