Optical oversampled analog-to-digital conversion

Abstract

Previously,1 we introduced a new method of optical analog-to-digital conversion based on oversampling and error diffusion coding that offers the potential to extend resolution and conversion rates beyond that currently possible with other electronic or optical converters. In this new approach, the analog input signal is first optically sampled at a rate much greater than the Nyquist frequency and is then quantized by a modulator that incorporates one-bit quantizers and linear filters in a negative feedback architecture for the purpose of reducing in-band quantization noise. The output of the modulator is subsequently processed by a digital decimation filter, which removes the out-of-band noise and generates a high resolution digital approximation to the analog input signal at the signal's Nyquist rate. In this paper, we present experimental results from the first demonstration of an optical first-order noninterferometric modulator and discuss both spatial and temporal extensions of this optical error diffusion technique to multidimensional applications.