Enhancing the performance of LP mode multiplexing devices via incident angle optimization of the array beam

Multiplane light conversion (MPLC) technology employs wavefront matching algorithms to enhance the design flexibility of optical devices. However, the realization of MPLC devices necessitates the construction of reflective components, which require the incident beam array to be incident on the device at a specific angle. Consequently, optimizing MPLC devices based on the angle of the incident beam is crucial for improving the performance of LP mode multiplexing devices. We applied MPLC technology to optimize the LP mode multiplexing device across a range of 0° to 32° based on the beam's incident angle. Numerical simulations revealed that the mode crosstalk of the optimized LP mode multiplexing device is below -24 dB, significantly improving the LP mode multiplexer. We optimized and fabricated an LP multiplexer with a 32° beam incidence angle, which was utilized in communication experiments to demonstrate the multiplexing of LP 01 , LP 11 , and LP 21 modes over a 5 km few mode fiber transmission. The BER curve of the communication experiment is below the forward error correction threshold, indicating that optimizing the angle of MPLC equipment can effectively improve the performance of LP mode multiplexing devices.