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Proceedings Paper

In situ optical time-domain reflectometry (OTDR) for VCSEL-based communication systems
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Paper Abstract

Optical time-domain reflectometry (OTDR) is an effective technique for locating faults in fiber communication links. The fact that most OTDR measurements are performed manually is a significant drawback, because it makes them too costly for use in many short-distance networks and too slow for use in military avionic platforms. Here we describe and demonstrate an automated, low-cost, real-time approach to fault monitoring that can be achieved by integrating OTDR functionality directly into VCSEL-based transceivers. This built-in test capability is straightforward to implement and relevant to both multimode and single mode networks. In-situ OTDR uses the transmitter VCSEL already present in data transceivers. Fault monitoring is performed by emitting a brief optical pulse into the fiber and then turning the VCSEL off. If a fault exists, a portion of the optical pulse returns to the transceiver after a time equal to the round-trip delay through the fiber. In multimode OTDR, the signal is detected by an integrated photodetector, while in single mode OTDR the VCSEL itself can be used as a detector. Modified driver electronics perform the measurement and analysis. We demonstrate that VCSEL-based OTDR has sufficient sensitivity to determine the location of most faults commonly seen in short-haul networks (i.e., the Fresnel reflections from improperly terminated fibers and scattering from raggedly-broken fibers). Results are described for single mode and multimode experiments, at both 850 nm and 1.3 μm. We discuss the resolution and sensitivity that have been achieved, as well as expected limitations for this novel approach to network monitoring.

Paper Details

Date Published: 10 February 2006
PDF: 10 pages
Proc. SPIE 6132, Vertical-Cavity Surface-Emitting Lasers X, 61320A (10 February 2006); doi: 10.1117/12.644176
Show Author Affiliations
Gordon A. Keeler, Sandia National Labs. (United States)
Darwin K. Serkland, Sandia National Labs. (United States)
Kent M. Geib, Sandia National Labs. (United States)
John F. Klem, Sandia National Labs. (United States)
Gregory M. Peake, Sandia National Labs. (United States)

Published in SPIE Proceedings Vol. 6132:
Vertical-Cavity Surface-Emitting Lasers X
Chun Lei; Kent D. Choquette, Editor(s)

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