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Proceedings Paper

Feedback in close-coupled axial VCSEL-photodiode pairs
Author(s): Kent M. Geib; Darwin K. Serkland; Gregory M. Peake; Victoria M. Sanchez
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Paper Abstract

We have been investigating the use of coaxial multimode VCSEL/PD (vertical cavity surface emitting laser/photodiode) pairs for positional sensing with emitter to target mirror distances on the order of 1mm. We have observed large variations in signal levels due to the strong optical feedback in these close-coupled systems, employing either heterogeneously integrated commercial components or our own monolithically integrated devices. The feedback effect is larger than anticipated due to the annular geometry of the photodetector. Even though there is very little change in the measured VCSEL total output power, the optical feedback induces variations in the transverse mode distributions in these multimode VCSELs. The higher order modes have a larger divergence angle resulting in changes in the reflected light power incident upon the active detector area for a large range of emitter/mirror separations. We will review the experimental details and provide strategies for avoiding these variations in detected power.

Paper Details

Date Published: 7 February 2011
PDF: 6 pages
Proc. SPIE 7952, Vertical-Cavity Surface-Emitting Lasers XV, 79520M (7 February 2011); doi: 10.1117/12.872909
Show Author Affiliations
Kent M. Geib, Sandia National Labs. (United States)
Darwin K. Serkland, Sandia National Labs. (United States)
Gregory M. Peake, Sandia National Labs. (United States)
Victoria M. Sanchez, LMATA Government Services (United States)

Published in SPIE Proceedings Vol. 7952:
Vertical-Cavity Surface-Emitting Lasers XV
James K. Guenter; Chun Lei, Editor(s)

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