Effect of shift in refractive index of dispersive elements in waveband-shift-free optical-phase conjugator based on DFG

In this study, the effect of the shift in the refractive index between two dispersive elements on the output phase-conjugated (PC) wave power of waveband-shift-free optical-phase conjugators based on difference-frequency generation (DFG-OPCs) is analyzed. First, a numerical model of the DFG-OPC is built by considering the shift ∆n in the refractive index. The derived formula shows that the output PC wave power of DFG-OPCs depends on the shift in the refractive index. Subsequently, the dependence of the output PC wave power on the shift is confirmed analytically. Calculations indicate that the output PC wave power varies according to the shift. For a relatively fractional shift ∆n = 1.0e-6, the output PC power is degraded by 3 dB. Finally, acceptable values of the shift and temperature difference are calculated as functions of the length of the dispersive element. It is illustrated in this study that the acceptable value of shift in the refractive index increases as the length of the dispersive element is reduced and that the output PC wave power can be stabilized against changes in temperature.

This is a post-peer-review, pre-copyedit version of an article published in Optical Review. The final authenticated version is available online at: https://doi.org/10.1007/s10043-021-00647-7.