| 摘要 |
PURPOSE:To obtain an optical output with no frequency variation resulting from modulation by alternately arranging a period when the driving currents of a semiconductor laser are modulated and controlled, and a period when modulation is stopped or weakened. CONSTITUTION:A modulation control circuit 46, a half mirror 35a, an optical switch 48, a sweep circuit 64 and a sweep control circuit 64a are added. The modulation control circuit 46 stops or weakens a vibration signal fed to a drive circuit 34 from a signal source 38 only for a desired period. The optical switch 48 synchronizes beams obtained by branching output beams from a laser diode 11 by a half mirror, etc. with stoppage and control by the modulation control circuit 46 and passes them, thus acquiring wavelength stabilizing output beams. Accordingly, an optical output with no frequency variation resulting from modulation is obtained. |
