DESIGN AND DEVELOPMENT OF A HIGH-SPEED ELECTROOPTIC A/D CONVERTER.

A detailed analysis of a high-speed electrooptic guided wave analog-to-digital (A/D) converter has been performed. It is concluded that the development of converters in the 4-6 bit 1-2-GS/s range should be feasible. Analyses are presented which detail the design considerations for the electrooptic modulator chip, the laser sampler, and the analog signal amplifier. A design plan is presented for a 6-bit 1-GS converter which utilizes an array of 6 LiTaO//3 interferometric waveguide modulators to perform the conversion and a frequency-doubled mode-locked Nd:YAG laser to perform the sampling of analog signals having 500-MHz bandwidths. Preliminary waveguide device results are also reported, including the successful demonstration of an interferometric modulator with a 17-dB (98-percent) extinction ratio.