Silica glass optical fibers have revolutionized data transmission, sensing and laser development over the past 50 years. Moreover, dielectric waveguides with a hollow core offer exciting development possibilities beyond traditional technology. Hollow Core Optical Fibers (HCFs) have been fabricated over the past 20 years with various geometries and refinements, yet their attenuation has remained significantly higher than can be routinely achieved in standard silica single mode fibers. Here we present recent developments in Nested Anti-resonant Nodeless Fiber (NANF) design over the last few years and show how this rapidly developing technology has been refined to produce state of the art HCFs at wavelengths between 850 – 1625 nm.

Real-time MIMO DSP is challenging but essential for practical deployment of coupled-core multicore fiber transmission systems as well as mode-division multiplexed transmission systems. We implemented a real-time MIMO DSP which can equalize four spatially-coupled signals (or four spatial modes) with dual polarizations by utilizing FPGA boards. With the real-time MIMO DSP, we show an experimental demonstration of real-time transoceanic transmission over coupled-core multicore fibers. The WDM DP-QPSK signals were transmitted over 7,200-km coupled-core four-core fibers and demodulated by real-time MIMO DSP. We also show the first real-time QAM transmission over coupled-core four-core fibers.