Pedro Corredera

TL;DR: In this paper, the authors present an experimental and theoretical description of a high-visibility phase-sensitive optical time domain reflectometry (φOTDR) and its performance when used for ultrasonic vibration measurements.

TL;DR: In this paper, the authors have developed a new technique to significantly extend the measurement distance of a distributed Brillouin Optical Time-Domain Analysis (BOTDA) sensor by using distributed Raman Amplification in the sensing fiber.

TL;DR: In this paper, the authors present an experimental and theoretical description of the use of first order Raman amplification to improve the performance of a Phase-sensitive optical time domain reflectometer (φOTDR) when used for vibration measurements over very long distances.

TL;DR: A new method to extend the range of Brillouin optical time domain analysis (BOTDA) systems is proposed that exploits the virtual transparency created by second-order Raman pumping in optical fibers and can be increased up to 100 km with 2 meter resolution.

TL;DR: It is shown in this Letter that modulation instability (MI) can induce a position-dependent signal fading in long-range φOTDR over conventional optical fibers, which leads to a complete masking of the interference signal recorded at certain positions and therefore to a sensitivity loss at these positions.