Patent ID: 6574251
Filing Date: 2003-06-03
Classification: H01S

Abstract:
A method of stabilizing the emission wavelength of a first optical source emitting coherent optical radiation at a first frequency, the method being performed with the assistance of a second optical source emitting coherent optical radiation at a second frequency substantially displaced from the first frequency and a two-photon absorber, the method comprising causing optical energy from the first and second sources at the first and second frequencies to be simultaneously incident on the two-photon absorber which responds to the incident optical energy at the first and second frequencies from the first and second sources to derive an electric beat signal having a beat frequency equal to the difference between (a) twice the frequency of one of the incident frequencies and (b) the frequency of the other incident frequency, and controlling the emission wavelength of the first optical source in response to a component of the beat frequency of the electric beat signal.