Laser light generating apparatus and method

A laser light generating apparatus comprising:

• a laser light source for outputting laser light;
• a phase modulator and a signal generating unit for generating a modulating signal to be applied to the phase modulator;
• a plurality of resonators including a first resonator and a second resonator disposed in a stage succeeding the first resonator;
• a nonlinear optical element disposed in the first resonator;
• an optical path length varying means for changing length of an optical path of each of the resonators;
• an optical system disposed between the laser light source and the resonators and between two resonators for providing coupling between the laser light source and the resonators and between the two resonators;
• a photodetector for receiving light from each of the resonators;
• and
• a control circuit having a negative feedback configuration for obtaining an error signal from a detection signal obtained by the photodetector and the modulating signal and controlling the optical path length varying means by an FM sideband method using the error signal;
• wherein the laser light is inputted to the phase modulator, subjected to phase modulation, and then inputted to the first resonator, and light generated by the nonlinear optical element is inputted to the second resonator;
• and
• the light from each of the first resonator and the second resonator is detected by the photodetector, and the length of the optical path of each of the resonators is controlled on the basis of the error signal, whereby the plurality of resonators are or can be simultaneously held in a resonant state.