Intensity noise of erbium-doped fiber laser based on full quantum theory

Abstract

Traditionally, by means of full quantum theory, we present the intensity noise transfer function of an Er-doped fiber laser, on the basis of which we analyze the spectrum of the intensity noise. Our theoretical results are in agreement with the existing experiment results. This model explains not only how the noise is produced, but also how the spontaneous emission and dipole fluctuations have an effect on the output noise, which cannot be explained via rate equation theory. We analyze the physical sources of various contributions to the noise spectrum as well. The simulation results show that the noise of the Er-doped fiber laser mainly consists of the vacuum noise resulting from the output coupling, dipole fluctuation noise, the pump source intensity noise, and the spontaneous emission from the upper level to the ground level, which provides the theoretical basis for noise suppression. Compared to the solid laser, the Er-doped fiber laser shows lower resonant relaxation oscillation frequency.