High spatial and spectral resolution long-range sensing using Brillouin echoes

High spatial (~cm) and spectral (~MHz) resolution Brillouin sensing is realized with enhanced signal to noise ratio using a pre-activated acoustic field and an optical phase control over the interrogating pulse. Pre-activation of the acoustic field preserves the Brillouin natural linewidth and a differential gain technique extends the method to long ranges. Experimentally, fully resolved measurements of the Brillouin frequency shift of a 5 cm spot perturbation at the far end of a 5 km fibre have been performed with a frequency resolution of 3 MHz ( 2 sigma ), using a 500 ps (5 cm) pi phase shift pulse

Long-range and high-resolution distributed Brillouin fiber sensors | Capteur Brillouin réparti à fibre optique à haute résolution et longue portée

Brillouin-based distributed optical fiber sensors have been the subject of intense research in recent years because they offer a unique solution for continuous, real-time monitoring in civil engineering and petroleum industry. These sensors provide strain or temperature measurements with meter spatial resolution over several tens of kilometers. In this work we demonstrate two new Brillouin fiber sensors with enhanced performances based on advanced modulation formats from high-speed lightwave communications systems. We first report a Brillouin distributed sensor with enhanced centimeter resolution using a digital phase-shift keying technique. The second one uses a quadrature phase-shift keying modulator as a single-sideband modulator to balance the pump depletion and the fiber loss by the Brillouin gain. Combined with a specially-designed in-line bidirectional Erbium-doped fiber amplifier, we demonstrate that this technique allows for the achievement of long-range distributed sensing over 100 km

Experimental observation of Brillouin linewidth broadening and decay time in photonic crystal fiber

We present a novel distributed sensing technique that makes possible the observation of Brillouin gain spectral distribution and acoustic decay time in photonic crystal fiber as well as in standard single-mode fiber

Observation of Brillouin linewidth broadening and decay time in photonic crystal fiber

We present a novel distributed sensing technique that allows for the observation of Brillouin gain spectral distribution and acoustic decay time in photonic crystal fiber as well as in standard single-mode fiber

Photon and phonon coupling by electrostrictive forces in photonic crystal fiber

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Expérience d'optique non linéaire dans les fibres photoniques : supercontinuum amplification Raman, mélange à quatre ondes et diffusion Brillouin

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