Nonlinear Laser Noise and Coherence

Abstract

The effect of spontaneous emission noise on the coherence properties of a laser operating above thresbold is considered on the basis of a noise‐driven van der Pol oscillator model. The oscillator constants are derived from the theory of Lamb. The noise function is represented as a sequence of randomly phased, damped sine pulses with a Doppler spread of frequencies. The noise function is normalized on the basis of equilibrium considerations at positive temperatures. The nonlinear linewidth, intensity fluctuations, and intensity correlation function are derived.