Conductus, Inc.

Uttam Goshal

Yongming Zhang

Noshir B Dubash

Vsevolod Kaplounenko

A digital optical receiver and clock recovery circuit for use in detecting and retiming optical data transmitted at rates up to and exceeding 40 Gb/s. The receiver is made, in part, of superconducting Josephson junctions. The receiver includes an optical signal detector, an SFQ (single flux quantum) transition detector for converting the signal from the photodetector into a stream of single flux quantum signals, and a clock recovery circuit. The clock recovery circuit includes a superconducting ring oscillator in which an SFQ pulse rotates and provides a clock signal at an output of the oscillator. When a pulse from the stream of single flux quantum pulses arrives from the transition detector, two pulses are generated in the ring oscillator. One of the pulses eliminates the rotating SFQ pulse and the second pulse replaces the rotating SFQ pulse, thereby recovering the phase of the clock signal in one bit.

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Austin, TX, United States of America

Uttam Goshal