Analysis of ring launching scheme using hollow optical fibre mode converter for 10 Gbps multimode fibre communication

A ring launching scheme using a mode converter based on hollow optical fibre (HOF) is theoretically investigated for the purpose of increasing bandwidth for multimode Gigabit Ethernet communication. The mode converter based on HOF transforms the fundamental mode of a single-mode fibre (SMF) to a ring-shaped mode. It has the characteristic to improve the bandwidth by exciting higher-order modes of the multimode fibre (MMF) selectively. The HOF launch is studied under various aspects such as induced coupling efficiency, mode power distribution, and bandwidth-length product and is compared to centre and offset launching schemes. It is shown that the ring launching scheme is expected to support 10-Gb Ethernet applications using conventional multimode fibres.