Power spectrum measurement of a modulated semiconductor laser using an interferometric self-homodyne technique: influence of quantum phase noise and field correlation

The amplitude-phase coupling effect introduces important dynamic line broadening in modulated semiconductor laser systems. The theory of a technique allowing measurement of the broadened spectrum using a single laser is presented. The quantum phase fluctuations of the lasing field are shown to be of great importance to the photocurrent spectrum of the mixed fields. Expressions for the photocurrent spectrum, which is shown to measure the optical field modulation power spectrum, are derived. Measurement results illustrating the theory are also presented