Lithium niobate microphotonic modulators

This work addresses the physics and engineering challenges which must be overcome to create a new class of small, light-weight, power-efficient, RF-photonic devices for use in indoor wireless communication applications. It is possible that opto-electronic solutions for indoor wireless systems may out-perform purely electronic versions. To achieve this goal, a new microphotonic mm-wave receiver architecture with direct electrical-to-optical conversion is presented. Central to such an architecture is the microphotonic optical modulator. This active optical component directly converts the received RF carrier frequency to an optical carrier frequency by interaction of optical and RF electric fields via the electro-optic effect. The modulator uses high- Q RF and microphotonic electro-optic resonators which are operated in simultaneous resonance. Fabrication of these new devices in the electro-optic material Lithium Niobate, and application of advanced RF coupling designs enable efficient interaction of RF and photonic electromagnetic fields. Simulations indicate that efficient modulation of an optical carrier at RF in the mm-wave range can be realized. Experimental results approaching 100% optical modulation at GHz frequencies in the RF, optical, and timedomain are presented. In addition, experiments demonstrating modulation of an optical carrier at RF in the mm-wave range are reported. This introduction of an active microphotonic modulator in an electro optic material creates an entirely new dimension to contemporary microresonator research that has never before been investigated.