Narrow Pulse Of High Current Laser Diode Driver System

Since the first laser came to the world in 1962, great changes of semiconductor laser have taken place. Semiconductor Laser is considered as one of the greatest inventions in the 21 century for it has promoted the rapid development of the other science and technology. The injection semiconductor laser, whose output can be modulated from its injected current, has become most popular because of its compactness, convenience of using, mature techniques and simple driver. Nowadays, the application of semiconductor devices has entered into big current era from its traditional small current filed. High-precision laser radars and 3D vision systems with millimeter resolution require high-power picoseconds optical pulses from laser diodes with direct current pumping in order to satisfy the requirements of low price, compactness and high reliability. But there is a definite distance between China and its counterparts in research fund about this subject. Oversea mature products have been commonly available for years. But the high prices seriously preclude the universal applications of such techniques. While in China, semiconductor laser drivers are mainly focused on low current about tens of mill ampere, which are used in optical fiber communication systems. The reports referring to large current and narrow pulses are quite few.This article analyses the operation principle of the semiconductor laser in detail. Based on its fundamental requirement under pulsed working way and avalanche principle, combined the system target, ZTX415 avalanche transistor is chosen as a switch and power transistor to put out narrow pulses with a width of 7 nanoseconds and pulse value of 10 amperes for the semiconductor lasers driver. An over frequency circuit and temperature controller are designed as well to make sure the system can run stably for a long time.The target of semiconductor laser driver attained: pulse rate rang 500Hz to 50 KHz;pulse width 5 ± 5ns;pulse current 10 ampere;pulse rising/falling time is less than 5 nanoseconds.