GaSb-based single-mode distributed feedback lasers for sensing (conference presentation)

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1117/12.2252951
AuthorSearch for: 1; Search for: 1; Search for: 1; Search for: 1; Search for: 2
Name affiliation
  1. National Research Council of Canada. Information and Communication Technologies
  2. National Research Council of Canada. Security and Disruptive Technologies
FormatText, Address
Proceedings titleSmart Photonic and Optoelectronic Integrated Circuits XIX
Series titleProceedings of SPIE; no. 10107
ConferenceSPIE OPTO, Jan. 28 - Feb. 2 2017, San Francisco, CA, USA
ISSN0277-786X
1996-756X
ISBN9781510606555
Abstract
GaSb-based tunable single-mode diode lasers can enable rapid, highly-selective and highly-sensitive absorption spectroscopy systems for gas sensing. In this work, single-mode distributed feedback (DFB) laser diodes were developed for the detection of various trace gases in the 2-3.3um range, including CO2, CO, HF, H2S, H2O and CH4. The lasers were fabricated using an index-coupled grating process without epitaxial regrowth, making the process significantly less expensive than conventional DFB fabrication. The devices are based on InGaAsSb/AlGaAsSb separate confinement heterostructures grown on GaSb by molecular beam epitaxy. DFB lasers were produced using a two step etch process. Narrow ridge waveguides were first defined by optical lithography and etched into the semiconductor. Lateral gratings were then defined on both sides of the ridge using electron-beam lithography and etched to produce the index-grating. Effective index modeling was used to optimize the ridge width, etch depths and the grating pitch to ensure single-lateral-mode operation and adequate coupling strength. The effective index method was further used to simulate the DFB laser emission spectrum, based on a transfer matrix model for light transmission through the periodic structure. The fabricated lasers exhibit single-mode operation which is tunable through the absorption features of the various target gases by adjustment of the drive current. In addition to the established open-path sensing applications, these devices have great potential for optoelectronic integrated gas sensors, making use of integrated photodetectors and possibly on-chip Si photonics waveguide structures.
Publication date
PublisherSociety of Photo-optical Instrumentation Engineers
LanguageEnglish
Peer reviewedYes
NPARC number23002226
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