Optoelectronic thyristor-based photonic smart comparator for analog-to-digital conversion

A new photonic comparator approach to optoelectronic A/D conversion is demonstrated using an optoelectronic thyristor. The comparator has both digital optical output (since the thyristor itself is a laser in the "on" state) and electrical output that is analog or digital. The electrical output subtracts from the input and passes the result to the comparator input of the next lower order bit. High-speed operation is expected due to the elimination of stored charge in the thyristor structure. The thyristor characteristics are measured and the predicted comparator operation is verified using discrete devices at low frequencies.