Systems applications of vertical-cavity multi-quantum well optoelectronic modulators

A large portion of the 'optical computing' research over the last 10 years has been centered around vertical cavity optoelectronic modulators. These devices have several characteristics which make them desirable from a systems standpoint: low power dissipation, high speed, large contrast ratio, bandwidth, dense arrays, integration with silicon VLSI, and WDM capability. This thesis examines systems applications of these devices.;Early experiments using a configuration of two of these devices known as a symmetric self electro-optic effect device to perform threshold logic are discussed and compared with similar devices for Boolean logic. An application of these modulators to optical neural networks is discussed. Modulators are used as output devices and integrated with MESFET circuitry and GaAs photodetectors.;Next, I discuss a reflection/transmission modulator (or X-modulator), a very powerful device for optical computation, routing, and interconnection. The device is essentially a 3 input, 3 output conservative and reversible switch, an optoelectronic implementation of a Fredkin gate. The use of these devices for optical logic is exhibited. Using arrays of these modulators, reconfigurable switching, routing, and interconnection networks are constructed, including crossbar switches and field programmable gate arrays. Ongoing research is focussed on improving their characteristics and making them more flexible for systems applications. In particular, reduced operating voltages, optical control, and dual zone structures containing gain layers are investigated.;Next, a new technology offered by AT&T at a workshop given last summer which involves smart pixels based on quantum well modulators and detectors flip chip bonded on to silicon VLSI chips is described. This technology has already demonstrated 1000's of optical inputs and outputs on a single chip and thus achieving aggregate data rates approaching 1 Tb/s. This technology has been used here to implement 2 x 2 switches (similar to the X-gate above) and a 4 x 4 optical crossbar switch for comparison with similar structures implemented using X-modulators.;Lastly, phase characteristics of modulators are studied. Asymmetric coupled quantum wells and oscillator strength modulation are used to produce a device with zero phase change over an entire switching range. A study of device tradeoffs for zero chirp devices is presented.