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Updated: Oct 20, 2025

Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping
Published on: March 20, 2017
Frequency multiplexed coherent φ-OTDR
Hannah M Ogden1, Matthew J Murray2, Joseph B Murray2
1U.S. Naval Research Laboratory, 4555 Overlook Ave., SW, Washington, DC, 20375, USA. hannah.ogden.ctr@nrl.navy.mil.
Abstract:
We present a comprehensive analysis of a frequency multiplexed phase-measuring φ-OTDR sensor platform. The system uses a train of frequency-shifted pulses to increase the average power injected into the fiber and provide a diversity of uncorrelated Rayleigh backscattering measurements. Through a combination of simulations, numerical analysis, and experimental measurements, we show that this approach not only enables lower noise and mitigates interference fading, but also improves the sensor linearity. We investigate the sensor dependence on the length of the pulse train and characterize the sensor performance as a function of range, demonstrating operation from 1 to 50 km. Despite its relative simplicity, this platform enables state-of-the-art performance, including low crosstalk, high linearity, and a minimum detectable strain of only 0.6 p[Formula: see text] in a 10 km fiber with 10 m spatial resolution and a bandwidth of 5 kHz.
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