SPECTRAL PROPERTIES OF AN INJECTED LASER

The theory in which the laser is interpreted as a nonlinear amplifier and filter is applied to the calculation of its spectral density in th e case of a homogeneous medium. The method is extended to an injected laser in which the source term includes both the spontaneous emission and the injected signal. Linewidth narrowing or widening, spectral amp lification or attenuation are described, using simple semiclassical fo rmulas.