Frequency stabilization of laser diodes at 0.83 μm using a fiberoptic coupler

Frequency stabilization of a fiber pigtailed laser diode discriminator is reported. The fiber coupler acts as a nearly-balanced-arm Michelson interferometer. The peak transmission signal is used for feedback control of the injection current of the laser diode. Because the sensing port can be isolated from the signal transmission port, the package design is very simple and can be implemented in an all-fiber fashion. The frequency fluctuation of a 0.83-μm test laser stabilized by this method is less than ±4 MHz. This scheme is applicable to longer-wavelength (1.2-1.6 μm) laser diodes; the stabilized lasers can be packaged easily