Raman-Assisted Brillouin Distributed Temperature Sensor Over 100 km Featuring 2 m Resolution and 1.2 $^{\circ}$C Uncertainty

Abstract

Abstract-Raman assistance in distributed sensors based on Brillouin optical time-domain analysis can significantly extend the measurement distance. In this paper, we have developed a 2 m resolution long-range Brillouin distributed sensor that reaches 100 km using first-order Raman assistance. The estimated uncertainty in temperature discrimination is 1.2 C, even for the position of worst contrast. The parameters used in the experiment are supported by a simple analytical model of the required values, considering the main limitations of the setup.Index Terms-Brillouin scattering, distributed optic fiber sensor, distributed Raman amplification, Raman scattering, temperature sensor.

Strong Cancellation of RIN Transfer in a Raman-Assisted BOTDA Using Balanced Detection

“…The trace reveals the imperfect polarization scrambling that was carried out, showing a larger polarization noise in the first kilometers of the fiber under test. The actual measured trace noise is comparable to the trace noise in other Ramanassisted BOTDA experiments over the same distance with 64 times more averaging [1].…”

“…It is interesting to compare now this setup, in terms of figure of merit (FOM) [9], with the same setup not using balanced detection [1]. While in [1] the FOM estimated was 108, in the present setup, the FOM has been raised to 500, which implies a fivefold improvement.…”

“…1. It is an evolution of a previous firstorder Raman assisted BOTDA setup [1] prepared by this group, where the detection part has been modified to include balanced detection.…”

“…In order to do so, it is needed to increase the signal-to-noise ratio (SNR) of the system, especially when measuring in the far end of the fiber. In the past few years, several techniques have been applied trying to achieve such goal [1]- [3].…”

Distributed Brillouin Fiber Sensor With Enhanced Sensitivity Based on Anti-Stokes Single-Sideband Suppressed-Carrier Modulation

“…Several techniques have recently been proposed to overcome these limitations and to extend the sensing range beyond 50 km. For instance, the sensing range can be extended to 100 km by using distributed Raman amplification schemes [4], or 150 km by combining frequency-division multiplexing and in-line Erbium doped fiber amplifiers (EDFAs) [5]. 120-km range has also been achieved by improving the SNR with optical pulse coding techniques and optical pre-amplification at the receiver [6].…”