Frequency stabilization of a laser diode by means of an optical wedge etalon

A novel laser diode (LD) wavelength stabilization system based on an optical wedge interferometer is presented. The proposed system uses an interference pattern from an external wedge etalon to detect frequency changes via a differential photodetector. Based on the etalon photodetector output signal, the feedback electronic circuit controls the LD current so as to obtain the LD wavelength as close as possible to the value set as a reference. Theoretical basis, design of the prototype system and metrological feasibilities of the device are presented. The absence of wavelength modulation during frequency stabilization, simplicity and low cost are the main advantages of the proposed technique.