Raman crosstalk in fiber-optic hybrid CATV systems with wide channel separations

The transfer function of nonlinear Raman crosstalk in fiber-optic systems is investigated both experimentally and analytically. When the channel separation is wide enough, the frequency response of the Raman crosstalk can be significantly changed by the effect of polarization-mode dispersion. Matched polarization state between the two channels at the fiber input does not necessarily ensure the worst case crosstalk for all frequency components. The implication of this effect in design of fiber-optic hybrid CATV systems is discussed.