Wavelength monitoring of single-mode diode laser using guided-wave interferometer

A new technique for continuous monitoring of the output wavelength of single-mode diode lasers is reported. In this approach, a small portion of laser output is coupled into a all-single-mode fiber interferometer. Observation of interferometer outputs can be directly and uniquely related to the output wavelength and its temporal variation. In preliminary results we could trace the behavior of the output wavelength as a function of temperature with an accuracy of about 5 A.