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Full-Text Articles in Engineering
Spectral And Spatial Quantum Efficiency Of Algaas/Gaas And Ingaas/Inp Pin Photodiodes, Steven Alan Tabor
Spectral And Spatial Quantum Efficiency Of Algaas/Gaas And Ingaas/Inp Pin Photodiodes, Steven Alan Tabor
Dissertations and Theses
This thesis reports a novel system capable of testing both the spectral responsivity and the spatial quantum efficiency uniformity of heterostructure photodiodes using optical fiber coupled radiation. Testing was performed to confirm device specifications. This study undertakes to quantify the spectral bandwidth of an AlGaAs I GaAs double heterostructure photodiode and two InGaAs I InP double heterostructure PIN photodiodes at D.C., through the use of spatial scanning. The spatial scanning was done using lasers at 670 nm, 780 nm, 848 nm, 1300 nm, and 1550 nm, coupled through singlemode optical fiber. The AlGaAs I GaAs material system covers the 600 …
Field-Equation Approximations And Amplification In High-Gain Lasers: Analytical Results, Lee W. Casperson
Field-Equation Approximations And Amplification In High-Gain Lasers: Analytical Results, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
In a related study the equations governing a high-gain laser amplifier have been solved numerically without making the usual slowly-varying-amplitude derivative approximation in Maxwell’s equations, and thus the field amplitudes are not restricted to vary negligibly in a distance of one wavelength. The results reveal an instability that involves reflections and oscillatory growth of perturbations away from steady state. In the present study steady-state solutions of the field equations are obtained analytically, and transformations are described for converting the equations to alternative intensity-equation sets. These intensity equations are linearized and solved for the growth rate and oscillation period of the …
Field-Equation Approximations And The Dynamics Of High-Gain Lasers, Lee W. Casperson
Field-Equation Approximations And The Dynamics Of High-Gain Lasers, Lee W. Casperson
Electrical and Computer Engineering Faculty Publications and Presentations
Semiclassical models for laser-dynamics studies typically incorporate a derivative approximation that reduces the second-order wave equation for the electric field to a first-order equation. It is shown here that this approximation and further frequency approximations are not necessary and may lead to significant errors for some high-gain laser systems. A more exact analysis also reveals a partial decoupling of the electric and magnetic fields that occurs with fast transient phenomena. These ideas are illustrated in terms of well-known dynamical effects.
Self-Pulsation Operating Regime For The Absorber Of A Twin Section Laser Diode, Gerald Farrell, P. Phelan, Joe Hegarty
Self-Pulsation Operating Regime For The Absorber Of A Twin Section Laser Diode, Gerald Farrell, P. Phelan, Joe Hegarty
Articles
The voltage-current characteristic of the absorber of a twin section laser diode is investigated as a function of the gain section current. For self pulsation to occur the absorber must be operated within a specific region of the voltage-current characteristics. This region only exists for absorber voltage current characteristics which contain an S-shaped negative resistance.