Resonance amplifier model describing diode lasers coupled to short external resonators

A model of a regenerative resonance amplifier has been used to describe Fabry-Perot GaAs diode lasers coupled to short external resonators. The optical gain and the equivalent input of the resonance amplifier are controlled by means of appropriate rate equations. Homogeneous line-broadening and proportionality between gain and electron density have been assumed in this approach. The model was applied to a diode laser coupled to an external plane mirror placed at a variable distance from one diode mirror. A numerical evaluation of the coupling coefficient between laser and external cavity enables to predict the measured power output and mode selective properties of the coupled system. A similar analysis was done for diode lasers coupled to external hemispherical resonators. The model calculation confirms the previously demonstrated mode selective properties of the hemispherical configuration which permitted stable single mode operation.