Frequency-controlled cw tunable GaAs laser

Abstract
A cw single‐mode tunable GaAs diode laser has been locked to an external passive cavity by making use of the dependence of the output frequency on the injection current. The resulting long‐term stability of the laser optical frequency was checked by reference to a microwave frequency standard, through the light‐shift effect in a cesium vapor. The laser frequency was found to track the drift of the cavity bandpass with residual variations less than 300 kHz rms. Servo‐controlled frequency scanning was achieved over 5 GHz.