Driver circuit of semiconductor laser for interferometry

The design of a driver circuit for high-stability semiconductor laser is introduced. Its output current can be continuously adjusted from zero to two hundred milliamperes and its stability reaches 1.5×10-5. The variation of the output current is less than 1μA when its operation time is longer than 12h. The modulation of frequency and intensity of optical wave in the laser interferometry can be achieved by the modulated current (100kHz～300kHz) input, whose modulation depth is continuously adjustable from zero to one hundred milliampere. By applying the grating external cavity semiconductor laser and the auxiliary temperature-control current driven by the driver current to the interferometry, the laser output with stable power and single wavelength was obtained to eliminate the mode hopping phenomenon of lasers and to realize the longdistance measurement for small vibration.