  Optical bistability provides a simple way to control light with light. We
demonstrate low-power thermo-optical bistability caused by the Joule heating
mechanism in a one-dimensional photonic crystal (PC) nanobeam resonator with a
moderate quality factor (Q ~ 8900) with an embedded reverse-biased pn-junction.
We show that the photocurrent induced by the linear absorption in this compact
resonator considerably reduces the threshold optical power. The proposed
approach substantially relaxes the requirements on the input optical power for
achieving optical bistability and provides a reliable way to stabilize the
bistable features of the device.
