A Simplified Fabry–PÉrot Electrooptic-Modulation Sensor

A simplified electrooptic (EO)-sensing system that employs a wavelength-tunable laser diode and an EO-crystal microcavity is presented. A theoretical model simulating a Fabry-Perot-based Pockels-effect probe demonstrates that both the EO phase retardation and modulation-efficiency slope of the optical system can be resonantly enhanced. Consequently, it predicts that electric-field measurements are possible using a configuration that eliminates the polarizer, analyzer, and quarter-wave retarder of typical EO intensity modulators. An experimental verification of the concept is presented using thin, uncoated, LiTaO crystals, and an EO modulation signal that is 60 dB above the system noise floor obtained.