Evaluating dispersion of optical fiber by analyzing the temporal mode property of Raman scattering

We theoretically and experimentally demonstrate the influence of dispersion on the temporal mode properties of the spontaneous Raman scattering pumped by picosecond pulses in single mode optical fiber. We model the process of the ultrafast spontaneous Raman scattering, calculate and measure the intensity correlation function of the Raman photons with different dispersion by varying the detuning between pump and Raman photons or changing the optical length. The intensity correlation function decreases with the increase of dispersion induced temporal walk-off both by increasing the detuning and by increasing the fiber length. We evaluate the dispersion parameter of the single mode fiber by fitting the measured data with the theoretical equation we deduced. The estimated value is close to the labelled one. Our study provides a new way to evaluate dispersion parameters of the media in which Raman scattering can occur and is beneficial for efficient distillation of entanglement in optical fibers.