Linearly Polarized Mode Demultiplexing Hybrid Based on Multi-Plane Light Conversion

In order to address the challenges of complex optical front ends of coherent receivers in mode division multiplexing (MDM) fiber communication systems, we propose a linearly polarized (LP) mode de-multiplexing hybrid (MDH) to implement the coherent detection of multiple MDM channels simultaneously based on the multi-plane light conversion technology. This MDH realizes the functions of mode demultiplexing and optical 90-deg mixing with combination of multiple input LP mode signals and the required local oscillator signal, using seven phase plates. After the theoretical modeling and parameter optimization, the proposed MDH can achieved significant performance improvements with insertion loss (IL) of only 1.62dB, mode dependent loss (MDL) of 0.34dB, and crosstalk of -17.42dB. The results show that the proposed MDH has the advantage of greatly simplifying the complex coherent optical front end of large-capacity MDM coherent fiber communication systems.