Method of polarization-maintaining photonic crystal fiber nonlinear response measurement using phase shift between orthogonal polarization modes

Nonlinear refractive index n2 is the material parameter, which is used to describe the strength of phenomena caused by third-order nonlinearity, so measuring it accurately is one of the key tasks of nonlinear optics. Several techniques to estimate n2 of the PCF have been demonstrated, but for example Z-scan is not suitable for any type optical fibers, because this method only allows to estimate n2 of the material preform of the PCF. Other methods, such as four-wave mixing, self-phase modulation, cross-phase modulation allow qualitatively good estimation of n2 only when pump wavelength is close to the zero dispersion wavelength (ZDW) of the optical fiber. In this paper, we present a new method of polarization-maintaining photonic crystal fiber nonlinear refractive index measurement using phase shift between orthogonal polarization modes.