Patent ID: 8331409
Filing Date: 2012-12-11
Classification: H01S

Abstract:
1. A laser device for locking a target laser in frequency, comprising: an optical frequency reference device that produces an optical reference frequency of high precision and stability; a reference laser that is tunable in frequency and produces reference laser light that is locked in frequency relative to the optical reference frequency of the optical frequency reference device; an optical interferometer that includes two optical paths that optically interfere with each other and receive the reference laser light from the reference laser, and a tunable optical delay device in the two optical paths that is adjustable to tune an amount of optical delay produced by the tunable optical delay device; a delay control device that controls the tunable optical delay device to cause the tuning of the amount of optical delay produced by the tunable optical delay device; a first photodetector that is coupled to the optical interferometer to receive light of optical interference of the two optical paths based on received reference laser light from the reference laser, the first photodetector configured to convert the light of optical interference into a first detector signal; a first locking circuit that receives the first detector signal and controls the delay control device based on the received first detector signal to lock a relative delay between the two optical paths of the optical interferometer to the reference laser in frequency; a target laser that is tunable in frequency and produces target laser light at a target laser frequency, the target laser being coupled to the optical interferometer so that the target laser light is coupled into the two optical paths of the optical interferometer to cause optical interference of the target laser light in the two optical paths; a second photodetector that is coupled to the optical interferometer to receive light of optical interference of the two optical paths based on received target laser light from the target laser and produces a second detector signal; and a second locking circuit that controls the target laser to tune the target laser frequency based on the second detector signal in a way that locks the target laser to the optical interferometer in frequency without being locked to the optical reference frequency of the optical frequency reference device.