Optical frequency comb generator control device
A purpose of the present invention is to provide an optical frequency comb generator control device capable of obtaining a stable output by performing a control of a resonator length or a light source frequency such that a control point is located at a position where an optical frequency comb is generated most widely. A carrier frequency component of an optical frequency comb emitted from an optical resonator of an optical frequency comb generator as a transmitted light or a reflected light is attenuated by an optical filter, an optical frequency component extracted via the optical filter is received by a photodetector 6 to detect an optical intensity, and an optical resonant length of the optical resonator or a light source frequency of an incident light is feedback controlled by a resonance control unit by using a detection signal of the photodetector.
1 . A control device of an optical frequency comb generator comprising an optical modulator for performing an optical modulation of incident light in an optical resonator, the optical frequency comb generator control device comprising:
an optical filter for attenuating a carrier frequency component of an optical frequency comb emitted as a transmitted light or a reflected light from the optical resonator;
a photodetector for detecting an optical intensity by receiving an optical frequency component extracted from the optical frequency comb via the optical filter;
a resonance control unit to which a detection signal of the photodetector is supplied; and
a bottom position discriminator for discriminating a bottom position of a signal level of the detection signal of the photodetector,
wherein an optical intensity of the optical frequency comb in which the carrier frequency component is attenuated by the optical filter is detected by the photodetector, and an optical resonant length of the optical resonator or a light source frequency of the incident light is feedback controlled by the resonance control unit, and wherein the resonance control unit performs a feedback control with the bottom position of the signal level of the detection signal of the photodetector as a basis of a stabilization point, based on a discrimination output by the bottom position discriminator.
2 . The optical frequency comb generator control device according to claim 1 , wherein a plurality of modulation signals with different modulation frequencies are switched and supplied to the optical modulator.
3 . The optical frequency comb generator control device according to claim 1 , wherein the optical filter is a notch filter for attenuating the carrier frequency component of the optical frequency comb.
4 . The optical frequency comb generator control device according to claim 1 , wherein the optical filter is a high pass filter having a cutoff frequency near the carrier frequency component of the optical frequency comb.
5 . The optical frequency comb generator control device according to claim 1 , wherein the optical filter is a low pass filter having a cutoff frequency near the carrier frequency component of the optical frequency comb.
6 . The optical frequency comb generator control device according to claim 1 , wherein the optical filter is a band pass filter having one cutoff frequency near the carrier frequency component of the optical frequency comb.