Semiconductor Laser Drive System

In this thesis, the principles and operating characteristics of the semiconductor laser work a more detailed analysis, and, accordingly analyze and summarize the resulting electrical parameters, we can use the laser constant current drive system solutions right. The system is driven by a constant current module, and temperature control module can provide a maximum of 1000 mA drive current, and also supplies the drive current for the laser TEC temperature stabilized at 25 ?, in order to ensure the stability of the laser.Highlights of this paper is to design a laser constant current drive circuit, and its main components are: control module and the steady flow module. First by STM32F103 microcontroller target current setting, and then through the digital-analog conversion of the output signal of LM2678 step-down voltage regulator output current, and then sampled by the feedback network samples the output current feedback to the LM2678, the formation of a voltage control loop road, while the output current by analog to digital converter feedback to the microcontroller, and incremental PID control algorithm to adjust the output current which in turn form a further control loop in the microcontroller. Under the combined effect of two control loops have been very stable drive current.Temperature control module uses automatic temperature control principle. Temperature control module circuit using ADN8830 temperature control as the main chip and power tubes H-bridge driver circuit, heating or cooling state jointly controlled thermoelectric cooler(TEC), thereby forming a solid-state automatic temperature control system, thereby lasers work to achieve automatic temperature control.In this paper, eventually developed a laser drive system, with 8V ~ 40 V wide input range, the maximum output of 1000 mA, adaptive voltage to a load, the output voltage of up to 5V. Temperature control portion may be better in the long laser temperature stable at 25 ?. Finally, the system drives the semiconductor laser as the pump laser test ASE runtime showed a good performance.