A cascadable InGaAsP-InP optoelectronic smart pixel with low switching energy

We demonstrate for the first time a 1.3-μm wavelength optoelectronic InGaAsP-InP smart pixel switching circuit using monolithically integrated p-i-n photodiodes and heterojunction bipolar transistors, along with surface-mounted folded-cavity surface-emitting lasers. The circuit functions as a cascadable optical switch with an on/off ratio of 6, and a maximum optical input/output differential gain of 6. At a bit rate of 100 Mb/s, a record low switching energy of 30 fJ was observed while maintaining circuit gain and cascadability. This switching energy is the lowest reported to date for an optoelectronic smart pixel.