Proceedings Article | 10 October 2020
KEYWORDS: Beam propagation method, Finite element methods, Single mode fibers, Telecommunications, Nonlinear optics, Multiplexing, Numerical simulations
In order to achieve a lower crosstalk, a central core-assisted photon lantern (CCAPL) supporting LP01, LP11, LP21, LP31 and LP02 modes is proposed, whose performance is evaluated through numerical simulation based on BPM as well as FEM. Compared with the depressed-index central core PL, it can be found that the average mode loss are reduced by about 0.05 dB and 0.1 dB, while the corresponding worst mode crosstalk is reduced by 3.3 dB and 6.5 dB for the step-index (SI) and grade-index (GI) profile, respectively. For comparable performance, the length of the CCAPL can be about 3-cm shorter than that in the depressed-index central core case, which is easier to process and avoids secondary taper in some cases. With optimized structural parameters, the losses of LP01, LP11, LP21, LP31 and LP02 modes in the SI device achieve -0.09 dB, -0.05 dB, -0.04 dB, -0.04 dB, and -0.06 dB, respectively. On the other hand, the mode losses in the GI device come to -0.03 dB,-0.04 dB, -0.04 dB, -0.02 dB, and -0.12 dB respectively. Besides, the modes’ crosstalk of the SI type and GI type are below -22.3 dB and -21.0 dB for all modes, respectively. As a conclusion, the impact of the assisted core on GI devices is greater than that on the SI devices.
