Frequency Stability Requirements in Quasi-Integer-Ratio Time-Expanded Phase-S…

Time-expanded phase sensitive (TE-ϕ)OTDR is a recently reported technique for distributed fiber sensing that relies on the use of an electro-optic dual frequency comb (DFC) scheme. A distinctive f…

Seismic Monitoring With Distributed Acoustic Sensing From the Near-Surface to…

Distributed acoustic sensing (DAS) delivers real-time observation ofphysical perturbations such as vibrations or strain variations in conventional optical fibers with high sensitivity. The high den…

Distributed Sensors Assisted by Modulated First-Order Raman Amplification

In distributed optical fibre sensors, the measurement range is typically limited to a few tens of kilometers due to the fibre attenuation and the input pump power limits imposed by the emergence of…

Common-Path Dual-Comb Spectroscopy Using a Single Electro-Optic Modulator

Dual frequency comb (DFC) spectroscopy using electro-optic comb generators stands out for its flexibility, easy implementation, and low cost. Typically, two combs with different line spacing are ge…

Analysis and Reduction of Large Errors in Rayleigh-Based Distributed Sensor

Commonly, the frequency shift of back-reflection spectra is the key parameter to measure quantitatively local temperature or strain changes in frequency-scanned Rayleigh-based distributed fiber sen…

High-Resolution Chirped-Pulse Ø-OTDR by Means of Sub-Bands Processing

Dynamic Measurements of 1000 Microstrains Using Chirped-Pulse Phase-Sensitive…

This paper extends the capabilities of chirped-pulse phase-sensitive optical time-domain reflectometry to the measurement of large dynamic strains over hundreds of meters of standard single-mode fi…

Hermetic Carbon Coatings for Electro-Thermal All-Fiber Phase Modulators

Joule effect and thermal response of several carbon-coated fibers are modeled and analyzed. An electro-thermally driven all-fiber phase modulator based on these principles is proposed and a proof o…

A Contextual GMM-HMM Smart Fiber Optic Surveillance System for Pipeline Integ…

This paper presents a novel pipeline integrity surveillance system aimed to the detection and classification of threats in the vicinity of a long gas pipeline. The sensing system is based on phase-…

Fully Distributed Optical Fiber Strain Sensor With 10−12 ϵ/√Hz Sensitivity

Advanced optical fiber reflectometry techniques enable spatially distributed measurements of true relative deformations over the length of a conventional optical fiber cable. This methodology is at…