APL Photon. 3, 046101 (2018)

By harnessing photonic crystal waveguide technology, scientists in Japan have fabricated a miniature photodetector that is fast and highly responsive. The micrometre-scale device consists of an InP lateral p–n junction that features a waveguide and a buried InGaAsP absorbing region at the interface between the p and n regions. Experiments with 1.3 μm light indicate photodetection with a responsivity of 0.88 A W–1 while tests at 1.53 μm suggest a speed of operation of 40 Gbit s–1 at a forward bias of 0.2 V. In principle, the approach should make it feasible in the future to construct photoreceivers with a μm2 footprint that consume just 1 fJ per bit and do not need electrical amplifiers. Such devices could prove to be useful building blocks for densely integrated nanophotonics chips for applications in energy-efficient information processors and communications.