A study of long wavelength strained quantum well lasers
Wang, Ming-Cheng
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Permalink
https://hdl.handle.net/2142/22912
Description
Title
A study of long wavelength strained quantum well lasers
Author(s)
Wang, Ming-Cheng
Issue Date
1993
Doctoral Committee Chair(s)
Chuang, Shun-Lien
Department of Study
Electrical and Computer Engineering
Discipline
Electrical and Computer Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Electronics and Electrical
Computer Science
Language
eng
Abstract
In this thesis, the device physics of long wavelength strained quantum-well lasers is explored both experimentally and theoretically. The goal of this study is to understand how to optimize laser materials (active region and cladding layer) and cavity parameters (barrier height) so that the high-temperature, high-speed and long-term reliability characteristics of strained quantum-well lasers can be improved.
First, the strain effects on static lasing characteristics, including threshold currents and temperature sensitivities, of strained quantum-well lasers are investigated. Radiative recombination rates and nonradiative Auger recombination rates of 1.55 $\mu$m strained InGaAs/AlGaInAs quantum-well systems are measured using time-resolved picosecond photoluminescence techniques. Strain dependence of optical gains, spontaneous emission rates, and Auger recombination rates are examined theoretically, taking into account the valence band mixing effects. Both compressive and tensile strained quantum-well lasers are shown to be intrinsically capable of achieving better temperature performance than that of unstrained quantum-well lasers.
Second, high-voltage electron-beam-induced-current (HV-EBIC) imaging is used to study the degradation of commercial 0.98 $\mu$m strained quantum-well lasers. The reliability of 0.98 $\mu$m InGaAs/AlGaAs strained quantum-well lasers is found to be limited by the developments of facet defects, caused by the nonradiative surface recombination in the cladding layers at the laser facet.
Third, the high-temperature modulation dynamics of 1.3 $\mu$m AlInGaAs/AlInGaAs strained quantum-well lasers with various barrier heights are investigated. Differential gains and nonlinear gain factors are independently measured using the parasitic-free optical modulation technique. It is concluded that a sufficient barrier height is necessary to reduce the temperature sensitivity of the differential gain, which ensures better high-speed performance at high temperature.
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