| 摘要 |
PURPOSE:To stabilize an intermediate frequency by providing a chemical semiconductor substrate, an active region of a semiconductor laser, an optical guide path, a local oscillator, an optical frequency shifter and a feedback circuit. CONSTITUTION:In the semiconductor laser used for a local oscillator, the active region 6 and an external resonator are integrated on the same substrate 1. The stimulated laser light from the active region 6 isled through the optical guide path, reflected in the reflector and fed back again to the active region 6 to obtain a laser stimulated light 13 of a narrow spectrum line width. The frequency of the laser stimulated light 13 is shifted so as to obtain a desired intermediate frequency by an optical frequency shifter 14 to obtain a local oscillating light 15. The fluctuation of the intermediate frequency is detected by a frequency discrimination circuit 22 and the low frequency component is fed back to the temperature of the semiconductor laser via a feedback circuit 21 and the high frequency component is fed back to the frequency shift quantity of the optical frequency shifter 14 and the drive current of the semiconductor laser. Thus, the intermediate frequency is made stable. |
