Dual-Probe Linearly Configured BOCDA System With Enlarged Modulation Amplitude

Abstract

We introduce a linearly configured Brillouin optical correlation-domain analysis (LC-BOCDA) sensor that uses a dual-probe wave and control of the correlation order to enlarge the frequency modulation amplitude of the deployed optical signals. The system is able to compensate the signal distortions and noise that impaired previous single-probe LC-BOCDA setups for frequency modulations larger than half the Brillouin frequency. These impairments are found to have originated in the Brillouin loss of the pump and in the beating of pump and probe spectral components at the receiver, both of which are avoided in this new sensor configuration. Applying our technique, we experimentally demonstrate an LC-BOCDA sensor, in which the frequency modulation amplitude can be increased to 9 GHz, leading to nearly twofold enhancement of the number of spatially resolved measurement points.