Design and Fabrication of Highly Linear Electro-optic Modulators

ABSTRACT:Modulator linearity and efficiency, in addition to bandwidth, are important parameters in characterizing a modulator. In general, improving modulation efficiency is highly desirable since higher modulation efficiency allows lower RF signal to impose equivalent change in the optical beam whereas improved linearity increases the dynamic range available to analog signals conveyed and processed by optical means. The lowering of required input RF power reduces complexity of a system utilizing a modulator by eliminating RF amplifier stages, reduce heat dissipation, and enhance sensitivity; better linearity of modulation suppresses spurs and improves the fidelity of optical transmission and processing. At the same time, modulation efficiency or linearity improvements must not limit the operational frequency, or bandwidth, for the modulator to retain its utility in a given application.BENEFIT:The proposed research effort under this SBIR attains both substantially enhanced efficiency and linearity improvement while preserving the broad bandwidth of operation. It does so by exploiting heretofore unexplored phenomena in the dynamics of electro-optic modulation. As such, the modulators developed under this SBIR program will find application in optical communication and in the nascent field of RF photonics that places premium value on the improved linearity and extended dynamic range of the optical links, while preserving or extending the bandwidth. Such improvements of modulator characteristics may transform the field of RF photonics, which uses optical beams as a medium to convey and process RF signalsparticularly at high frequencies where optical fibers offer significant advantages over conventional RF waveguides in terms of size, weight, and loss.