Eight Modes Selective Elliptic-Core Photonic Lantern in MIMO-Free Mode Division Multiplexing Systems at S plus C plus L Bands

We propose an elliptical-core mode selective photonic lantern (EC-MSPL), which can be well matched to mode division multiplexing (MDM) systems without multiple-input multiple-output (MIMO). The taper region of the small package satisfying the adiabatic condition is obtained through two-stage taper related parameter optimization, which can reduce the length of the taper region without affecting the PL performance. Finally, we simulated the results for step-index EC-MSPL and graded-index EC-MSPL at taper lengths of 10 cm and 5 cm, respectively, using the beam propagation method. Both types of PL can achieve low-loss mode conversion and crosstalk below -15.6 dB at 1550 nm wavelength. At the same time, the coupling efficiencies of the two PL modes in the S+C+L bands are higher than 85% and 71%.

Automated summary

We propose an elliptical-core mode selective photonic lantern (EC-MSPL) that is suitable for mode division multiplexing (MDM) systems without multiple-input multiple-output (MIMO) capability. By optimizing the taper related parameters in a two-stage approach, we obtain a small package taper region that satisfies the adiabatic condition, enabling a shorter taper length without affecting the performance of the photonic lantern (PL). Simulations show that both step-index and graded-index EC-MSPLs can achieve low-loss mode conversion and crosstalk below -15.6 dB at a wavelength of 1550 nm, with coupling efficiencies above 85% and 71% for the two PL modes in the S+C+L bands.