All-optical variable-in variable-out wavelength converter based on cascaded nonlinearity in aperiodic optical superlattice

We theoretically report a new method to achieve variable-in, variable-out wavelength conversion in LiNbO3 with aperiodic optical superlattices (AOS) structure. The optimal structure of the LiNbO3 sample was obtained through simulated annealing method. About 3.4-nm prescribe pump bandwidth at 1559 nm is achieved to fulfill variable wavelength conversion among four selected ITU signal channels (C23-C20). As the result of large pump bandwidth, the reduced effective nonlinear coefficient of the AOS sample decreases to 0.21. Fluctuation of the operation temperature, variation of the incident angle and the errors in poling process show little influence on the performance of the device.