All-optical bistable switching in an active InGaAs quantum-well waveguide

The authors have observed low-power optical bistability in an active strained InGaAs single-quantum-well waveguide which is biased with a quasi-constant current injection 20% below the threshold current. Although the output power measured after the output collecting lens is half of the peak input power measured before the input focusing lens, it is believed that this is mainly due to the inefficient coupling into a slab mode, and that optical switching occurs with net gain in the device. A channel waveguide with a similar active medium would operate with constant DC electrical bias and should provide significant overall gain.<>