Demonstration of an optoelectronic 4-bit analog-to-digital converter usinga thyristor smart comparator

An optoelectronic analog-to-digital converter (ADC) approach with 4-bit ope ration is demonstrated based on the combination of HFETs and an optoelectro nic thyristor. The optoelectronic thyristor implements the comparator funct ion and generates both optical digital and electrical output. The basic com parator function is combined with HFET differential amplifiers to form a sm art comparator (SC) which becomes a building block that may be cascaded N t imes to form an N-bit ADC. In this paper, one SC is used in a feedback loop with the appropriate clocking to achieve 4-bit operation. When the optoele ctronic thyristor and the HFET amplifiers are fabricated as a monolithic in tegrated circuit, multi-GB/s operation is expected. (C) 2000 Elsevier Scien ce B.V. All rights reserved.