公开(公告)号：JPH01276786A

公开(公告)日：1989-11-07

申请号：JP5398089

申请日：1989-03-08

Applicant: CSELT CENTRO STUDI LAB TELECOM

Inventor： PIERO GANBINI

IPC: H01S5/068 ,  H01S5/0687 ,  H01S5/40 ,  H04B10/155

Abstract: PURPOSE: To enable compensation for a wide-range frequency oscillation by performing the light analysis of a light signal emitted from a laser, transforming the spectrum signal into an electric signal and finding the derivative of the electric signal to extract an error signal. CONSTITUTION: A light signal emitted from a laser 1 is supplied to a modulator 2 and a control device 100. A beam directed to the device 100 is given to a spectrum analyzing device. A distance between the mirrors of an interferometer 6 is corrected by an piezo-electric device 10 receiving the output of a tilt voltage generating device 11. A detector 12 transforms the output of the interferometer 6 into electric signal to supply it to a differential circuit 14. A comparator 15 detects the zero point of intersection of a derivative signal to transform 16 a detection signal into a pulse. A sample and hold circuit 17 accords a tilt signal from the generating device 11 to the zero point of intersection of the interferometer spectrum derivative to perform sampling. A sample from the circuit 17 is given to a differential amplifier 19 through a low-pass filter 18 and compared with a reference signal VR. An error signal outputted from the amplifier 19 compensates for the frequency change of the laser 1.