Impact of pulse characteristics on the sensing spatial resolution for Raman distributed optical fiber sensors

Raman distributed optical fiber sensors can be applied to the real-time distributed measurement of the temperature along the sensing fiber. The sensing spatial resolution of Raman distributed optical fiber sensors is a key property. Firstly, the paper examines the impact of pulse energy time-domain distribution characteristics on the sensing spatial resolution. The relationship between effective pulse width and sensing spatial resolution in pulse with arbitrary energy distribution is investigated through experimental analysis. Then, this study examines the effect of pulse spectral linewidth on sensing spatial resolution. The experimental evidence indicates that the reduction in sensing spatial resolution with increasing sensing distance is predominantly attributable to the dispersion of Raman anti-Stokes light, rather than the dispersion of the input pulse. Finally, the equation of Raman anti-Stokes scattering signal in timing is theoretically reconstructed. These conclusions provide a theoretical basis for technical solutions to improve the sensing spatial resolution by optimizing the timing characteristics of the pulse source and for the optimization and compensation of Raman anti-Stokes light dispersion.