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Author Witjaksono, Gunawan ♦ Botez, Dan
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ AMPLITUDES ♦ FEEDBACK ♦ LASERS ♦ PHYSICS ♦ QUANTUM EFFICIENCY
Abstract Surface-emitting diode lasers containing a second-order Bragg grating with a central phaseshift, {Delta}{phi}, of values around {pi} are found to fundamentally favor lasing in a mode of symmetric near-field amplitude profile, which in turn provides emission in a single-lobed beam orthonormal to the surface. Devices of 500 {mu}m long distributed-feedback (DFB) active region ({lambda}=0.98{mu}m) and 500 {mu}m long distributed feedback reflector passive regions provide, for {Delta}{phi}={pi}, a surface-emitted beam pattern with 88% central-lobe power content, and external differential quantum efficiency, {eta}{sub D}, of 51%. Since the guided field is antisymmetric to start with, and a central {pi} phaseshift causes two grating-outcoupled beams to be out-of-phase with each other, the net result is a single-lobed far-field pattern. The guided-field peak-to-valley (intensity) ratio, R, in the active (i.e., DFB) region is only 2, which insures single-mode operation to high powers, since the intermodal discrimination is high ({ge}100 cm{minus}1). Over a wide range in {Delta}{phi}:60{degree}; {eta}{sub D} remains high ({gt}50%) and the degree of guided-field uniformity remains low (R{lt}2). {copyright} 2001 American Institute of Physics.
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-06-25
Publisher Place United States
Journal Applied Physics Letters
Volume Number 78
Issue Number 26


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