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The derivation of a novel closed form model for multiple-state quantum-dot semiconductor optical amplifiers (QD-SOAs) is discussed. Results suggest the simplicity and accuracy of the proposed model.

A simple, accurate and fast multilayer feedforward artificial neural network (ANN) model is developed for quantum-dot semiconductor optical amplifiers (QD-SOAs). The developed model has demonstrated excellent precisions and is used to create very interesting design curves for QD-SOAs.

An analysis for the inhomogeneous line broadening and the optical gain, which are derived from size fluctuation distribution, are studied. The effects of this on quantum dot density are also studied in detail.

An analysis of the gain characteristics of quantum-dot semiconductor optical amplifiers is reported and discussed.

The properties of InP-based microcavity light emitting diodes were studied for the effects of lateral optical confinement.

The indirect band-to-band absorption coefficient and electrooptic effect in SiGe-Si quantum well optical modulators were computed. The effect of the quantum well shape and the dimensions on the optical properties of the optical modulator was also analyzed. The shift of the electron wavefunction created significant changes in the absorption coefficient, the refractive index, and the linear optic coefficient. These changes show that the novel amplitude and phase modulators can be realized in this material system.

A model of the Light Amplifying Optical Switch (LAOS) based on a derived expression for the nonlinear current gain of the heterojunction phototransistor (HPT) provides input-output characteristics, static I-V curve and switching voltage. Study of I-V characteristics and the switching mechanism show that nonlinear current gain of the HPT and the early effect creates thyristor-like characteristics in LAOS.

A new physical model based on the determination of feedback current in light amplifying optical switch (LAOS) and the currents in heterojunction phototransistors (HPTs) helps measure the static I-V curve of LAOS. Solutions to the continuity equation in the HPT yield values for electrical and optical feedback current values. Feedback coefficients, recombination currents, early effect and collector to base doping ratio affect the negative resistance region in the I-V curve.

Examination of the influence of effective interface velocities on current gain and currents of passivated heterojunction bipolar transistors (HBT) shows that thermionic flux and effective interface velocities are determinants of the collector current and the space-charge region recombination current. The quasi-Fermi level discontinuity expression depends on the recombination current and the interface velocities. The expression for the current gain of the HBT agrees well with previously derived experimental values.

Gilbert-cell and photoreceiver circuits were designed for an integrated optical phase-locked, loop (OPLL) to generate stable channel offsets in dense wavelength-division multiplexing (DWDM). These circuits were fabricated using a p-i-n/heterojunction bipolar transistor layer structure. Various configurations of an OPLL employing Gilbert-cell phase detectors and photoreceiver circuits were tested, and wavelength separations from 1.0 to beyond 27.11 GHz were obtained. Index Terms - Dense wavelength-division multiplexing, integrated optoelectronics, laser stability, microwave bipolar integrated circuits, microwave photonics, monolithic-microwave integrated-circuit mixers, optical phase-locked loops, optoelectronic devices, OEIC's.