A filter-free scheme for orthogonally pumped polarization-insensitive optical phase conjugation of broad-band optical signals

Orthogonally pumped four-wave mixing is known as an effective technique for polarization-insensitive optical phase conjugation in optical fibers. However, for phase conjugation of broad-band optical signals, a wide pump wavelength separation is a necessity in order to avoid crosstalks. This can result in an increase in polarization sensitivity of the scheme. As a solution to this problem, we propose a filter-free scheme that automatically rejects unwanted four-wave mixing products, such that broad-band optical phase conjugation can be achieved with a narrow pump wavelength separation for improved polarization insensitivity.