Theory and experiments on unstable resonator quantum well GaAs/GaAlAs lasers

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:7120626

Mittelstein, M

Structures and performance of GaAs/GaAlAs lasers are investigated experimentally and theoretically. A self consistent model for the longitudinal gain and intensity distribution in injection lasers is introduced. The model is applied to unstable resonator semiconductor lasers to evaluate their lateral losses and quantum efficiencies, and an advanced design is presented. Symmetric, unstable-resonator semiconductor lasers are manufactured and a virtual source point inside the laser more than an order of magnitude narrower than the width of the near field is demonstrated. Young's double-slit experiment is adopted for lateral coherence measurements in semiconductor lasers. A high degree of lateral coherence indicates operation of the unstable-resonator lasers in predominantly one mode. In the pulsed measurements on broad-area, single-quantum-well, graded-index wave-guide, separate-confinement-heterostructure lasers, very high quantum efficiencies, very low losses, and very high output powers are observed. Beam divergence is narrower than two times the diffraction limit in single-lobed, far-field patterns. Using single-quantum-well lasers, the second quantized-state lasing is found experimentally, and a simple model developed. A general model for the gain spectrum and required current density of quantum-well lasers is introduced. The eigenfunctions and eigenvalues of the charge carriers and optical mode of the transverse structure are used to derive the gain spectrum and current density from the Einstein coefficients. The two-dimensional density of states for the charge carriers and the effective width of the optical mode (not the width of the quantum well) are the dominant parameters. A new heuristic approach accounts for the smeared onset of subbands, eliminating convolution calculations. Applications are presented for a typical structure, a conventional double heterostructure and an advanced structure.

• Research Organization: California Inst. of Tech., Pasadena, CA (USA)
• OSTI ID: 7120626
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
SEMICONDUCTOR LASERS
STABILIZATION
BEAM ANALYZERS
BENCH-SCALE EXPERIMENTS
QUANTUM EFFICIENCY
RESONATORS
STRUCTURAL MODELS
THEORETICAL DATA
DATA
EFFICIENCY
ELECTRONIC EQUIPMENT
EQUIPMENT
INFORMATION
LASERS
NUMERICAL DATA
SEMICONDUCTOR DEVICES
SOLID STATE LASERS
426002* - Engineering- Lasers & Masers- (1990-)