| 摘要 |
PROBLEM TO BE SOLVED: To provide a laser drive circuit and a laser driving method capable of precisely controlling a bias current and modulation current, according to temperature change and the changes with time during output operation of signal light. SOLUTION: A laser drive circuit 1a comprises a drive current generator 2 for supplying a drive current Id to an LD18, and a control unit 5 which controls intensity of bias current Ibias and modulation current Imod based on a light quantity signal Dmon after receiving the light quantity signal Dmon which is based on an optical current Imon from a PD19. The control unit 5 acquires a change (first change) of average level of the light quantity signal Dmon relative to the changes in the bias current Ibias, and acquires a change (second change) of average level of the light quantity signal Dmon relative to the changes in the modulation current Imod. It increases/decreases the bias current Ibias and modulation current Imod, so that a ratio Ratio of the first and second changes approaches a first specified value refRatio. COPYRIGHT: (C)2008,JPO&INPIT
|
