Polarization Dependence of Four-Wave Mixing in Dispersion-Shifted Fibers and Its Application to Nonlinear Refractive Index Measurements Using Maximum Mixing Efficiency

摘要

If the phase match condition is satisfied in a 1.55-μm dispersion-shifted fiber (DSF), four-wave mixing (FWM) between the signals is generated at a lower optical power level than other nonlinear phenomena. In this paper, the polarization dependence of the FWM generating efficiency is discussed. From the maximum mixing efficiency, the nonlinear refractive index and the zero-dispersion wavelength are simultaneously measured. Both DSFs of 20 and 4 km are used for studies of the polarization dependence of FWM light with respect to linear polarization from the wavelength variable DFB-LD. For a 20-km DSF, a nonlinear refractive index of n{sub}2 = 2.50×10{sup}(-20) m{sup}2/W and a zero-dispersion wavelength of λ{sub}0 = 1553.0 nm are obtained. For a 4-km DSF, n{sub}2 = 2.42×10{sup}(-20) m{sup}2/w and λ{sub}0 = 1557.9 nm. For the 4-km DSF, it is confirmed by the CW-SPM method that n{sub}2 = 2.40×10{sup}(-20) m{sup}2/W. The measured results for the two methods are found to be in good agreement.