Efficient and mode selective spatial mode multiplexer based on multi-plane light conversion

We demonstrate a new spatial mode multiplexer based on Multi-Plane Light Conversion with very low intrinsic loss (<; 4.1 dB) and high mode selectivity (crosstalk <; -23 dB). This multiplexer can perform any mode conversion, and we demonstrate its performance for 6 eigenmodes of a few-mode fiber.