SEMICONDUCTOR LASER DRIVING SYSTEM

摘要

PURPOSE:To stabilize light output easily and accurately by controlling the bias current and modulation current of a semiconductor laser which converts electric signal to optical signal for transmission in a signal processing circuit made of low speed circuit. CONSTITUTION:Electric signal from a signal generator 11 is input to a semiconductor laser driving circuit 12 which contains a control circuit for light output stabilization. The signal output from the driving circuit 12 is applied to a first semiconductor laser 16 to generate optical signal. A second semiconductor laser 17 is mounted on the same heat sink 15 as the semiconductor 16 and modulated by a signal from a low speed signal generator 13. The light emitted from the second semiconductor laser 17 is converted to electric signal by a photodetector 14 and input to the driving circuit 12. The peak value is detected by this low speed electric signal and the bias current of the first semiconductor laser 16 is feedback-controlled to keep the peak value constant.