Distributed Temperature Measurements Using Network Analysis Frequency-Domain Reflectometry

In this paper, we propose and demonstrate a network analysis Rayleigh scattering configuration for high resolution, distributed temperature measurements. In the proposed approach, a vector network analyzer (VNA) is employed to modulate the laser light adopting either a single-sideband (SSB), or a double sideband (DSB) modulation scheme, before being injected into the sensing fiber. The temperature changes are recovered by acquiring the Rayleigh spectral signature over a range of laser frequencies, and then determining the shift in the Rayleigh-scatter spectra induced by temperature at each fiber position.