Patent ID: 6122087
Filing Date: 2000-09-19
Classification: H04B

Abstract:
An optical-frequency-stabilized light source comprising:a local light source for generating light of an arbitrary optical frequency;a first optical splitter for splitting output light from said local light source into two parts;an optical multiplexer for combining one of the outputs of said first optical splitter with reference pulsed light;a first optical detector for detecting, based on the output light from said optical multiplexer, a pulsed beat signal which is a superimposition of a difference in frequencies between the frequency of the light from said local light source and the frequency of the reference pulsed light;a rectifier for rectifying a beat signal detected by said first optical detector, and for generating a rectangular pulse;a time measuring circuit for measuring the time at which the rectangular pulse from said rectifier is obtained in synchronization with a repetition period of said reference pulsed light;a frequency measuring circuit for measuring a beat frequency based on said beat signal detected by said first optical detector;calculation means for calculating the frequency of the light from said local light source based on output signals from said time measuring circuit and said frequency measuring circuit, and outputting a control signal corresponding to a deviation from a predetermined target optical frequency;a second optical splitter for splitting the second output of said first optical splitter into two parts and outputting one part from an output terminal;optical frequency discriminating means for outputting, based on the second output of said second optical splitter, an electrical signal corresponding to the optical frequency thereof;a control circuit for controlling the frequency of said local light source such that the signal from said optical frequency discriminating means remains an electrical signal corresponding to the target optical frequency; andoptical frequency discrimination control means for outputting a correction signal to said optical frequency discriminating means for correcting the relationship between the optical frequency of the light input to said optical frequency discriminating means and the electrical signal output by said optical frequency discriminating means, based on a control signal output by said calculation means.