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The identification of a chaotic emitter that consists of a semiconductor laser with an optical feedback is studied. The effect on the time-delay identification of the tunable parameters is studied and the difficult time-delay-identification scenarios have depended on the time-scales of the system dynamics as it undergoes a route to chaos.

The models of a GaInAs-AllnAs-based midinfrared quantum-cascade-lasers (QCLs) structure with optimized second-harmonic generation (SHG) capabilities are described using supersymmetric quantum mechanics (SUSYOM). The supersymmetric optimization process is an effective method to achieve higher nonlinearity of the lasing medium itself.

Photonic crystals waveguide (PCWs) obtained by introducing line defects in otherwise period 2-D PCs are explored with the aim of enhancing the typical poor and low-band-width transmission through tight bends. It is seen that the enhancement of power transmission ([nu] > 90%) across bandwidths of 95 nm, even without optimizing the corners is achieved with 30 degree PCW bends.

The process of 3-D simulations of terahertz spatiotemporal pulse shaping is examined. It is shown that 3-D simulation generates a more complete description than 2-D simulation by allowing for simulation of all parameters in a wider variety of structures.

The coherent control of excitons in quantum wells at high repetition rates is investigated. The aim was to pinpoint the practical constraints for application in high-bit-rate optical switching. A shaped optical gating pulse is used to control the areal density of excitons as well as the index of refraction at the signal frequency. The implementation of such a mechanism in 100-Gb/s optical systems is hampered by a tradeoff between optical pathlength and excitation density.

A theory that includes radiation dynamics and localized-exciton decay elucidates exciton-induced polaritons and intrinsic emissions in quantum wells, present in planar optical microcavities. Time-resolved photoluminescence spectroscopy measures the radiative decay and radiation dynamic parameters, related to the restricted and radiation modes of the optical field, and the relation between emission and temperature.

A theoretical proposal to explore the intrinsic exciton spontaneous emission (radiative lifetimes) in semiconductor quantum wires is discussed. Radiative destruction in low-dimensional systems varies with bulk, where recombination is necessarily dependent on phonons, impurities, defects, surfaces and interfaces. Radiative destruction of the order of 100 ps can be estimated. The influence of electromagnetic coupling in quantum-wire arrays was studied. It was concluded that excitons in quantum wells have greater intrinsic radiative decay periods than the excitons in quantum wires.