Development Of Driver For Semiconductor Laser Diode

Semiconductor laser diode with its outstanding features, in so many high-technology areas such as military, medical, industrial production, optical fiber communications is playing a pivotal role. The stability of the laser injection current and the operating temperature has a direct, significant impact on the output of laser diode, so it is of great importance to develop a high stability semiconductor laser driving source.This thesis analyzes the main factor that affected the stable output of laser diode and the required technical qualifications for the system have been determined and consequently, the driver system for semiconductor laser diode is designed based on the study of the principle and the characteristics of semiconductor laser diode.This driver system includes a current driver control section and a temperature control section. the current driver control section is based on the negative feedback principle, and according to the different amount of feedback, it is divided into two parts, automatic current control module and automatic power control module, which achieve the steady control of the injection current and output optical power of laser diode respectively. The temperature control section, which is also based on the closed-loop control theory, uses the control mode of proportion and integral, samplings the working temperature of the laser diode with a thermistor, controls the cooling and heating capacity of the thermoelectric cooler with the difference between the temperature set value and the sampling value as the control signal, and achieves the goal of automatic control of temperature.In addition, in order to prevent the potential safety hazard of the laser diode and the thermoelectric cooler during use, protection circuits such as ESD protection circuits, thermoelectric cooler protection circuit, current-limiting circuit, switching circuit, alarm circuit, amplitude limiter circuit, slow startup circuit, etc. are designed.Finally, the performance tests of this drive power system for semiconductor laser diode studied are done. The experimental results are proved that the 1 hour stability of the drive current control has reached 0.019%, the temperature control deviation has reached±0.01℃, all the technical qualifications have met the design requirements expected.