Frequency stabilized laser with electronic tunable external cavity

摘要

Method and arrangement for locking a laser to an external cavity that is electronically tunable to provide an optical source that is highly coherent and which is frequency stabilized over a variable frequency range. Preferably, an injection laser is tightly coupled to an external acousto-optic cavity having a reflective mirror on its back facet and carried on an electro-optic crystal substrate. A transducer is coupled to the external cavity and converts an electrical sinusoidal input signal into an acoustic wave which travels along the electro-optic crystal substrate to modulate the refractive index of the material along the optical waveguide. The periodicity of the refractive index along the waveguide is accordingly determined to be equal to one half wavelength of the acoustic frequency propagating in the waveguide which locks the laser at a particular optical frequency determined by the refractive index profile. The arrangement is particularly desirable for frequency division multiplexing applications.