Pulse Sharpening and Gain Saturation in Traveling-Wave Masers*

Abstract

A pair of coupled nonlinear differential equations is given which describes the reduction of gain in a traveling-wave maser due to high-power signals. Integrals in closed form are obtained for two cases of interest. The first applies to pulsed optical amplifiers where no replacement of stored energy occurs during a signal pulse. The result is a pulse sharpening phenomenon; i.e., the leading edge of an input pulse is amplified by the original full gain while later parts of the signal experience reduced gain. The second case is that of steady-state gain saturation in the presence of a continuous pumping process. The results describe the observed gain compression of microwave ruby traveling-wave masers.