Optical frequency control for DWDM networks using sum-frequency generation in multilayer waveguides

Future high bit-rate DWDM networks will require an ensemble of laser sources whose frequencies can be set accurately. Considering the excellent short-term wavelength stability of today's DFB semiconductor lasers, network frequency management could be accomplished through periodic measurement and correction of essentially free-running sources. We present experimental results on a novel technique for measuring and controlling the wavelength of a semiconductor laser using the non-linear properties of a multilayer waveguide. Using the described calibration procedure, absolute optical frequency control of a 1.3 μm DFB laser within better than 2 GHz is demonstrated. Our technique allows full flexibility in channel frequency assignment, is already compatible with projected DWDM network wavelength control requirements and lends itself to monolithic optical integration.