STABILIZED LIGHT SOURCE DEVICE

摘要

PURPOSE:To stabilize the intensity of an optical output by directly monitoring front light in output light from a semiconductor laser and controlling the intensity of the optical output. CONSTITUTION:A beam splitter 4 is arranged in the forward direction that output light (front light) from a semiconductor laser 1 is projected, and one part of incident light to the beam splitter 4 is branched and the branched light is received by a photodiode 5 for monitor. A light intensity signal corresponding to the quantity of light reception is generated by the photodiode 5 and the signal is outputted to an automatic output control circuit 3, and driving currents given to the semiconductor laser 1 are controlled automatically so that the light intensity signal is kept constant by the automatic output control circuit 3. A polarizer 6 is inserted on P-polarized branch, thus stabilizing the light intensity of the semiconductor laser 1 with high precision.