Cylindrical Vector Beam Multiplexing based on All‐Dielectric Fiber Meta‐Tips Enabling High‐Capacity Bidirectional Optical Communication

Abstract To advance sixth‐generation technology, a high‐performance backbone network with fiber‐rich interconnects and advanced optical multiplexing is essential. Cylindrical vector beam (CVB) multiplexing offers a promising solution to current challenges in channel capacity, integration, and unidirectional transmission. This study proposes and demonstrates an all‐dielectric, fiber meta‐tip‐enabled CVB multiplexing system for high‐capacity, bidirectional optical interconnects. The system employs fiber meta‐tips with metasurfaces (MSs) integrated onto the facets of multimode fiber (MMF) at both ends. The MS multiplexes and demultiplexes three channels by converting vector modes between CVBs in the MMF core and fundamental Gaussian beams in free space, leveraging light path reversibility for high‐speed bidirectional communication. Three‐channel CVB multiplexing combined with wavelength‐division multiplexing achieves an aggregate data rate of 75 Gbps and average bit error rate of 3.8 × 10 −9 per channel across data rates ranging from 2.5 to 12.5 Gbps at a received power of −12.2 dBm. The design supports higher‐speed, low‐latency, and scalable bidirectional optical interconnects for applications such as smart cities, intelligent transportation systems, and quantum communications.