Integration of a Resonant Tunnelling Diode and a Quantum Well Laser: Model and Experiment

A resonant tunnelling diode has been monolithically integrated with an optical communications laser (the RTD-LD) to form a simple optoelectronic integrated circuit (OEIC) that is a novel bistable device suitable for an optical communications system. The RTD-LD was based on a ridge-waveguide laser structure and was fabricated from an InAIGaAs/InP epi-wafer grown by molecular beam epitaxy; it emitted at around 1500 nm. Voltage controlled optical/electrical switching and bistability were observed during the characterisation of the RTD-LD -useful features for a fibre-optic communications laser. Optical and electrical simulations of the RTD-LD were carried out using the circuit simulation tool PSPICE. In addition, a discrete component version of the RTD-LD was constructed, which, along with the results of the simulations gave insight into the operating principles of the monolithically integrated RTD-LD.