Optimization of sideband modulation in optical-heterodyne-downmixed electro-optic sensing.

Enhancements of the modulation depth in an electro-optic sensing application, through optimization of the modulation sidebands in both an electro-optic modulator and a microcavity electro-optic probe, have been investigated. The principles and methods of optimizing the operational bias points for the devices are described from the point of view of both an electro-optic modulator and probe, and their different optimum characteristics for signal-modulation depth, due to their huge scale gap, are presented. We use an optical-heterodyne receiver employing a fast modulator along with the electro-optic sensing technique to achieve high-frequency microwave electric field mapping. The practical limitations to sensitivity enhancement, solutions for compensating distortion, and combined optimization conditions for both electro-optic modulation and sensing are presented by exploring the evolution of field-mapping distributions.