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. Howe ver, for phase conjugation of broad-band optical signals, a wide pump wavel ength separation is a necessity in order to avoid crosstalks, This can resu lt 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 con jugation can be achieved with a narrow pump wavelength separation for impro ved polarization insensitivity.