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\varepsilon /\sqrt {\textrm{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.
© 2022 Optica Publishing Group
Full Article | PDF ArticleMore Like This
Brandon Redding, Matthew J. Murray, Andrei Donko, Martynas Beresna, Ali Masoudi, and Gilberto Brambilla
Opt. Express 28(10) 14638-14647 (2020)
Matthew J. Murray and Brandon Redding
Opt. Lett. 45(18) 5226-5229 (2020)
Mengshi Wu, Xinyu Fan, Qingwen Liu, and Zuyuan He
Opt. Lett. 44(24) 5969-5972 (2019)