Research On Wide Pulse Width Modulating Technology For Laser Diode Driver

For the high power laser diode driving system, the characteristic of the outputcurrent is of great importance factors. With the continuous development of laser diode,it is becoming higher and higher to the requirement of the driving system. For thetraditional high power laser diode driver, the pulse width of output current are in asmall adjustment, and current overshoot will happen. In this paper, the high powerlaser driver technology which based on the principle of the differential amplifiercircuit is studied and the experimented. The temperature control system of laser diodehas carried on the design and optimization. The main content and innovation of thispaper is as follows:1. Put forward the design scheme of wide pulse width modulation technology forlaser drive system, including both of the driving system and temperature controlsystem. The laser diode driver that using differential amplifier circuit technology has awider current pulse width adjustment than other driving model, to meet the demandand various technical standard of laser diode driver.2. Through the researches on the static working point and small signal model ofdriving circuit, using the method of half circuit technology and open circuit timeconstant technology, we made a concrete analysis on the overall transfer function, thestep response characteristics and high frequency bandwidth of the circuit. Reduce theimpact of the influence of main influencing factors, optimize the step response andfrequency response characteristics, increase the adjustable range of output currentpulse width and frequency, and eliminate the phenomenon of current overshoot. Thesystem has very high level of reliability and security.3. Through the researches on sampling circuit of temperature signal, we improvedthe precision of temperature sampling. Optimize the temperature control programbased on PID automatic control theory. Improved the precision of constanttemperature degree of laser diode temperature control system.4. Set the experimental platform for measuring output power characteristics oflaser diode driver and measuring the stability of the temperature control system.Analyses and calculate the experimental data, the precision of output current value， the adjustment of output current pulse width. Calculate the stability of the temperaturecontrol system.