Robust optical control of an optical-amplifier-based flip-flop.

We demonstrate new optical techniques for externally controlling the latchable output power of a semiconductor-optical-amplifier-based flip-flop. Optical 'set' and 'reset' signals increase and decrease the re-fractive index, respectively, via cross-phase modulation (XPM). Set signals, which deplete the carrier density, have wavelengths between 1533 and 1568 nm, and powers as low as 22 microW. Reset is performed with carrier-generating 'positive' optical pulses at 1306 and 1466 nm, and minimum powers below 1 mW. These techniques are useful for digital optical-processing functions such as bit-length conversion, retiming, and demultiplexing.