Measurement of spectra of and correlation between FM and AM noises in GaAlAs lasers

Abstract

The FM- and AM-noise spectra of a CSP-type GaAlAs laser, and the correlation between FM and AM noises, were measured in the frequency range below 100 kHz with the bias current as a parameter. The measured spectra consist of power-independent 1/f noise and power-dependent white-noise components. A strong correlation is observed between the FM and AM noises when the output power is small. This fact supports the theory developed by Henry, in which the amplitude-phase coupling causes the linewidth increase.