Enhanced bandwidth distributed acoustic sensing using a frequency multiplexed pulse train and micro-machined point reflector fiber
Abstract
In this Letter, we present an enhanced bandwidth distributed acoustic sensor (DAS) that uses a frequency multiplexed interrogation system to probe a micro-machined point reflector fiber. The fiber contains a series of discrete point reflectors with reflectance as high as −48 dB, while the frequency multiplexed interrogator allows us to increase the effective pulse repetition rate by a factor of 10. Together, this enables a phase noise as low as −101 dB (re rad2/Hz) for a 2.5 km fiber with 10 m spatial resolution, corresponding to a strain noise of 0.095 p ε / Hz . This scheme also enables a 10-fold increase in the sensor bandwidth without introducing noise due to interference fading. Finally, we demonstrate sensing at ranges up to 10 km using a fiber containing 1000 point reflectors, illustrating the scalability of this approach.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 20, 2022
- Source ID
- 10.1364/ol.449223
Entities
People
- Brandon Redding
- Hannah M. Ogden
- Martynas Beresna
- Timothy J Lee
Organizations
- United States Naval Research Laboratory
- University of Southampton