Distributed Brillouin fiber laser sensor

Journal Article · 11 January 2022 · Optica

DOI: https://doi.org/10.1364/optica.435716 · OSTI ID:1841985

Murray, Joseph B.  ^[1]; Cerjan, Alex  ^[2]; Redding, Brandon  ^[1]

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1. Naval Research Lab. (NRL), Washington, DC (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies (CINT)

Brillouin fiber sensors can provide distributed strain and temperature measurements over long distances in standard off-the-shelf fiber by measuring the Brillouin frequency shift as a function of position along a fiber. The primary drawback of these systems is their limited sensitivity, which results from the challenge in identifying the Brillouin frequency shift to within a small fraction of the Brillouin linewidth. In this work, we introduce a technique that overcomes this fundamental limitation by establishing a series of lasing modes that experience Brillouin amplification at discrete spatial locations in the test fiber. The linewidth narrowing and high intensity associated with the lasing transition enable precise measurements of this lasing frequency. As an initial demonstration, we present a sensor that simultaneously excites 40 lasing modes in a 400 m fiber, providing a measurement of the strain at 40 discrete locations with a spatial resolution of 4 m. Each sensor exhibits a minimum detectable strain as low as 4 nε/Hz^1/2 with a dynamic range of >5 mε and a bandwidth of ~10 kHz. As the first demonstration that Brillouin lasing can be used for distributed fiber sensing, this work establishes an approach that could enable ultra-high strain sensitivity using off-the-shelf fiber.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC)
• Grant/Contract Number: NA0003525
• OSTI ID: 1841985
• Report Number(s): SAND--2022-0497J; 702564
• Journal Information: Optica, Journal Name: Optica Journal Issue: 1 Vol. 9; ISSN 2334-2536
• Publisher: Optical Society of AmericaCopyright Statement
• Country of Publication: United States
• Language: English