Polarization dependence and efficiency in a fiber four-wave mixing phase conjugator with orthogonal pump waves

We study the influence of pump separation on polarization dependence and on conversion efficiency in a fiber-based optical phase-conjugator with two orthogonal pump waves at different wavelengths. The polarization dependence is found to be minimized when the pump wavelength separation is small. Furthermore, both theory and experiments show that the efficiency is maximized if the signal wavelength is located close to one of the pumps.