Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Martins, HF (Author) Other; Martin Lopez, S (Author) Other; Corredera, P (Author) Other; Filograno, ML (Author) Other; Frazao, O (Author) FCUP; Gonzalez Herraez, M (Author) Other

Journal

Title: Journal of Lightwave Technology

Vol. 31

Pages: 3631-3637

ISSN: 0733-8724

Publisher: Optical Society of America

Indexing

ISI Web of Knowledge - 111 Citations

Scopus - 128 Citations

Other information

Authenticus ID: P-009-SWH

DOI: 10.1109/jlt.2013.2286223

Abstract (EN): Phase-sensitive optical time domain reflectometry (phi OTDR) is a simple and effective tool allowing the distributed monitoring of vibrations along single-mode fibers. Up to now, phi OTDRs have been used mostly for the measurement of sub-kHz vibrations, normally in the context of intrusion sensing. In this paper, the authors present an experimental and theoretical description of a high-visibility phi OTDR and its performance when used for ultrasonic vibration measurements. The use of a semiconductor optical amplifier in the setup allows to suppress coherent noise and also to improve the spectral response of the pump pulses. These two advantages greatly decrease the detected intra-band noise thus allowing frequency measurements in the limits set by the time of flight of the light pulses while maintaining the simplicity of the scheme, as no post-processing, extremely high coherence lasers or coherent detection methods are required. The sensor was able to measure vibrations of up to 39.5 kHz with a resolution of 5 m over a range which could go up to 1.25 km. This is the first time to our knowledge that a fully distributed measurement of ultrasonic waves was achieved. The statistical behavior of the system was also described theoretically and characterized experimentally.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7