Gain Spectrum Engineering in Distributed Brillouin Fiber Sensors

In this paper, a novel method for Brillouin optical time-domain analyzers exploiting the gain spectrum engineering will be proposed for the first time, to the best of our knowledge. By superimposing the Brillouin gain with two symmetric loss spectra, new degrees of freedom will be provided to engineer the spectrum of the Brillouin interaction. This leads to a Brillouin gain shape which is much more robust to noise influences than the conventional one. Simulations and experiment are in very good agreement to each other and demonstrate a more than 3-dB measurement accuracy enhancement. Since for the proposed method the frequency error is less susceptible to the fiber loss, the sensing range can be extended by up to 60%. This paper might open a new way to enhance and adapt the distributed Brillouin sensing performances by an engineering of the spectrum shape.