Patent ID: 6563848
Filing Date: 2003-05-13
Classification: H01S

Abstract:
A semiconductor laser drive device, comprising:a semiconductor laser that emits light; a detector that detects an amount of said light emitted by said semiconductor laser; a sample hold device, comprising: a comparator that compares a light radiation level command signal with a voltage signal related to an output current of said detector; a first switching device that selectively switches between a sampling mode, that samples a control current, and a holding mode, that holds said control current; and a capacitive device that stores an electrical charge; and a second switching device that selectively turns ON and OFF a current supplied to said semiconductor laser when said first switching device is switched to said holding mode, such that said current remains constant regardless of a change in temperature of said semiconductor laser due to said control current, representing a voltage output by said comparator, held by said capacitive device, wherein said first switching device and said second switching device are simultaneously switched when said first switching device and said second switching device are switched to said sampling mode.