Characterization of optical nonlinearity of a photonic crystal fiber in the spectral domain by cross-phase modulation using a pulsed pump

We report a cross-phase modulation (XPM) method to characterize optical nonlinearity of a photonic crystal fiber (PCF) in the spectral domain, C-band, by using a pulsed pump laser and a continuous wave signal laser. A nonlinear phase shift accumulated along the PCF was directly measured in the spectral domain by a high-resolution optical spectrum analyzer. The proposed technique was validated for a conventional step-index high nonlinear optical fiber with a known nonlinear parameter, to confirm its potential in efficiently characterizing the optical nonlinearity of an arbitrary PCF overcoming dispersion and insertion loss penalties.