All frequency domain distributed fiber-optic Brillouin sensing

A frequency domain approach to distributed fiber-optic Brillouin sensing is presented and numerically analyzed. In this technique, both measurements and signal processing are performed in the frequency domain. We use an integral equation which directly relates the Brillouin gain to the Brillouin signal in the frequency domain in order to develop a new technique for the quantitative reconstruction of temperature-strain profiles along an optical fiber. The reconstruction is achieved by minimizing a cost function representing the error between the measured and the model data. Such a minimization is effectively performed by representing the unknown (temperature-strain) profile with a finite number of parameters. Numerical results confirm the effectiveness of the proposed approach and its stability with respect to measurement errors.