Quantitative amplitude-measuring Φ-OTDR with pε/√Hz sensitivity using a multi-frequency pulse train
Abstract
We report an amplitude-measuring Rayleigh-based sensor that uses a series of frequency-shifted pulses to extract quantitative distributed strain measurements. By using frequency multiplexing, we are able to inject a train of 10 pulses into the fiber at once. This allows us to use a higher average input power than standard phase-sensitive optical time domain reflectometry systems, improving the sensitivity. The sensor recovers the strain by tracking the time-dependent amplitude of the Rayleigh backscattered light from all 10 pulses. This approach enables a sensor with a noise floor of 1.5 p ε / √ H z over 10 km of fiber with 12 m spatial resolution, a 5 kHz bandwidth, and a dynamic range of 80 dB at 1 kHz. The sensor exhibits a high degree of linearity and is immune to interference fading.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 14, 2020
- Source ID
- 10.1364/ol.400159
Entities
People
- Brandon Redding
- Matthew J Murray
Organizations
- United States Naval Research Laboratory