| 摘要 |
PURPOSE:To compensate laser oscillation delay time by comparing the duration of the optical output from a laser with a reference value to control the pulse current or bias current of the laser to stabilize the optical output and further controlling the width of the input electric pulse signal. CONSTITUTION:A pulse input signal as a rectangular wave is converted through a waveform shaper 11 into a triangular wave, which is applied to a pulse duration control circuit 12. Then, the output from the circuit 12 is applied to a semiconductor laser driving circuit 13, the output of which drives the laser 14. The light output from the laser 14 is convertered through a photodiode 15 into an electric signal, which is compared by a comparator 16 to which reference value 1 is applied with the reference value 1 to alter the pulse current in the circuit 13. At this time a pulse duration setting circuit 17 is newly added between the comparator 16 and the circuit 12 to control the duration of the triangular wave produced from the circuit 12. In this manner, the light pulse may become stable against the ageing change and temperature change. |
