Effect of optical feedback on a VCSEL TDLAS

• Published in: Applied physics. B, Lasers and optics Vol. 99; no. 3; pp. 585 - 589
• Main Authors: Vujanic, D., Jaeger, W., Tulip, J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2010; Springer
• Subjects: Biological and medical applications; Coherence; Collapse; Degradation; Engineering; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laser spectroscopy; Lasers; Optical Devices; Optical feedback; Optics; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Semiconductor lasers; laser diodes; Signal to noise ratio; Vertical cavity surface emission lasers; Wavelengths; Relative Intensity Noise; Laser Linewidth; Optical Power; Optical Feedback; Optical Feed; Vertical cavity laser; Semiconductor lasers; Optical feedback; Feedback; Second harmonic; Tunable lasers; Surface emitting lasers; Detection limit; Laser spectroscopy; Signal-to-noise ratio; Laser diodes
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-010-3970-5

This paper describes the effects of optical feedback on the sensitivity of VCSEL tunable-diode laser spectroscopy (TDLS). Three VCSELs, emitting at different wavelengths in the near-infrared, were used. A TDLS system, subjected to optical feedback, exhibited a common signal-to-noise ratio profile for all three lasers. A catastrophic degradation of TDLS sensitivity occurred when feedback exceeded a level which we associate with coherence collapse. The TDLS system had a CH
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minimum detection limit of 7.5 ppmm without optical feedback. Optical feedback of less than ten percent reduced this sensitivity by two orders of magnitude. This reduction of system sensitivity was accompanied by a second-harmonic absorption signal baseline shift which degraded the system accuracy.