Theoretical and Experimental Study of a Semiconductor Resonant Cavity Linear Interferometric Intensity Modulator

The phase response of an injection locked semiconductor laser that is used as the phase modulator in a resonant cavity linear interferometric intensity modulator is studied in detail. It is shown that, signal-to-intermodulation ratio of such a modulator is affected by the injection ratio, linewidth enhancement factor of the semiconductor laser, residual amplitude modulation, depth of phase modulation, and linearity of the resonant cavity response. Experimental measurements of the signal-to-intermodulation ratio of this modulator using a semiconductor Fabry-Pérot laser as the resonant cavity are in good agreement with the theoretically predicted values.