Accurate controlling system for the output and frequency of laser diodes

The change of the output power and the frequency of the light source of an optical fiber interferometer seriously affects the output of the interferometer.In order to get high output accuracy and stability from the optical fiber interferometer,the operation amplifier with high S/N,and a semiconductor cooler were used.A laser power driving system was designed.Through theoretical and experimental analysis,it was proved to provide laser diode(LD) with high stability and,high temperature controlling precision of ±0.01℃.The cooling driving current could reach 800mA.At the same time,it provides current control with high stability and constant control over output power,which assures the precision of the controlled wavelength to be ±0.1nm.The maximum LD driving current reaches 180mA,and the output curren stability could be kept among 10-4~10-5.The experimental data indicate the method is not only simple,but also highly accurate and stable in terms of temperature control.The application maintains the output wavelength of the laser diode at a constant level and assures the measure accuracy in optical fiber interferometer sensors(OFIS) and optical communication.