Abstract
Advancements in orbital angular momentum(OAM)mode-multiplexing communication networks require tunable mode filters for selective channel demultiplexing and downloading.In this study,we propose a spatial depth-dependent mode transformation strategy for the tunable filtering of OAM modes.By integrating the spi-ral phase and lens phase modulations,we achieved mode conversions that varied with the transmission depth,enabling selective demultiplexing in predetermined axial planes.This approach facilitates tunable mode filtering by adjusting spatial depths.As a proof of concept,we fabricated a mode filter using two-photon polymeriza-tion lithography(TPL)technology,successfully filtering five OAM modes with mode crosstalk below-10.9dB.Additionally,the filter was applied in a mode-multiplexing communication link,achieving tunable demultiplex-ing of five mode channels with bit error rates below 10-6.These results highlight the efficacy and flexibility of our strategy for OAM mode filtering and offer promising insights for the development of mode-multiplexing communication networks and channel interconnections.
维普
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