Numerical Investigation of the Performance of OAM-Mode Shifting Recirculating Delay Loop Under the Effect of Mode Shifter Displacement

We investigate the effect of OAM mode shifter displacement on the performance of the OAM-mode shifting recirculating delay loop by simulating the beam propagation using Kirchhoff-Fresnel diffraction. Simulation results indicate that 20 delayed replicas may be obtained with >10dB signal-to-crosstalk ratio (SCR) if alignment is perfect and $\ell_{\mathrm{shift}}$=+1.