Longitudinally resolved measurements of carrier concentration and gain in 980-nm InGaAs/GaAs high-power quantum well lasers

Andrew J. Bennett*, Edward H. Sargent, Rick D. Clayton, H. B. Kim, Jing Ming M. Xu

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Measurements of longitudinal variation in critical laser parameters such as gain and carrier concentration are invaluable in understanding and diagnosing device performance and failure mechanisms. However, traditional front-facet measurements cannot reveal the variation of these parameters along the length of the laser. Other methods require physical modifications to the laser itself, such as the fabrication of a top window, and are thus invasive. We describe a new experimental technique based on analysis of side spontaneous emission. A tapered optical fiber translated along the side of the laser using a micropositioner collects spontaneous emission from the active region, allowing spatially-resolved gain and carrier concentration measurements to be made. Such measurements can be used to track the evolution of dark lines caused by defects where non-radiative recombination is dominant. We applied this method to a 980 nm high power laser with an In0.2Ga0.8As, 80 angstroms SQW and facets of 90%/10% reflectivity. It was predicted through a 1D rate equation model that the carrier concentration would increase near the high-reflectivity mirror, due to lower optical field intensities. Using the bimolecular recombination equation to determine the carrier density, this expectation was confirmed. The peak modal gain also increased with proximity to the high-reflectivity mirror, and modulations in the gain peak profile attributed to spatial hole burning were observed.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsMahmoud Fallahi, S.C. Wang
PublisherSociety of Photo-Optical Instrumentation Engineers
Pages160-169
Number of pages10
ISBN (Print)0819424153
StatePublished - 1997
EventFabrication, Testing, and Reliability of Semiconductor Lasers II - San Jose, CA, USA
Duration: Feb 13 1997Feb 14 1997

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume3004
ISSN (Print)0277-786X

Conference

ConferenceFabrication, Testing, and Reliability of Semiconductor Lasers II
CitySan Jose, CA, USA
Period2/13/972/14/97

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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