An optoelectronic thyristor-based analog-to-digital converter for parallel processing

Abstract

A single pixel optoelectronic analog-to-digital converter is described which is suitable for two-dimensional (2D) arrays as would be required for a digital optical signal processor. The conversion is based upon the use of an optoelectronic thyristor in the form of the double heterostructure optoelectronic switch as a comparator. Using the switch configured as a VCSEL and one field-effect transistor load device, the comparator delivers the binary output optically and, at the same time, provides an electrical output to combine with the input signal to determine the next lower order bit. The function is similar to the algorithmic electrical converter with several optoelectronic advantages. Resolution of 10 bits is expected at speeds of 100 MHz with scaled transistor technology. The compact size of the circuit and the algorithm suggest a viable approach for conversion of 2D data arrays in real time.