We propose a modeling methodology tailored to predicting the wavelength and power output from a distributed Bragg reflector laser for use in quantum measurements. The relationship between power, wavelength, current, and temperature is acquired with a genetic algorithm (GA). The function set and termination set for GA are determined from the physical mechanisms of laser current, temperature, and output performance. To verify the validity of the method, measured data are divided into a training group and a test group. The test results show that our models can accurately predict the value of power and wavelength at the given current and temperature, with the RMSE of 13.4 μW and 6.0 × 10 − 5 nm, respectively. This method can help enhance the output performance of a laser.
The thermal effect problem is one of the key research issues in the design of semiconductor laser structures. The heat flow generated in the laser tube has a significant influence on the inherent characteristics of the structure. Thermal modal finite element analysis is an important method to study the influence of thermal load on the intrinsic properties of the structure. It is of great significance for the material selection and structural design of the laser. Based on the mechanical performance and temperature load requirements, this paper aims at the miniaturization of the overall structure. The internal thermal load is analyzed and applied. Based on this, the structure and structural parameters of the semiconductor laser are optimized.
Distributed feedback laser is widely used as the pump beam and probe beam in atomic physical and quantum experiments. As the frequency stability is a vital characteristic to the laser diode in these experiments, a saturated absorption frequency stabilization method assisted with the function of current and frequency is proposed. The relationship between the current and frequency is acquired based on the genetic programming (GP) algorithm. To verify the feasibility of the method, the frequency stabilization system is comprised of two parts that are modeling the relation between the current and frequency by GP and processing the saturated absorption signal. The results of the frequency stabilization experiment proved that this method can not only narrow the frequency searching range near the atomic line center but also compensate for the phase delay between the saturated absorption peak and the zero crossing point of the differential error signal. The reduced phase delay increases the locking probability and makes the wavelength drift only 0.015 pm/h, which converted to frequency drift is 7 MHz/h after frequency locking on the Rb absorption line.