Optimising O-to-U Band Transmission Using Fast ISRS Gaussian Noise Numerical Integral Model

We model the transmission of ultrawideband (UWB) signals, including wavelength-dependent fibre parameters: dispersion, nonlinear coefficient and effective fibre core area. To that end, the inter-channel stimulated Raman scattering Gaussian noise (ISRS GN) integral model is extended to include these parameters. The integrals involved in this frequency-domain model are numerically solved in hyperbolic coordinates using a Riemann sum. The model implementation is designed to work on parallel graphics processing units (GPUs) and is optimised for fast computational time. The model is valid for Gaussian-distributed signals and is compared with the split-step Fourier method (SSFM), for transmission over standard single-mode fibre (SSMF) in the O-band (wavelengths around the zero-dispersion wavelength), showing reasonable agreement. Further, we demonstrated SNR evaluation over an 80 km SSFM single-span transmission using 589$\times$96 GBaud channels, corresponding to almost 59 THz optical bandwidth, fully populating the O, E, S, C, L and U bands (1260$-$1675 nm). The SNR evaluation is completed in just 3.6 seconds using four Nvidia V100 16GB PCIe GPUs. Finally, we used this model to find the optimum launch power profile for this system achieving 747 Tbps of potential throughput over 80 km fibre and demonstrating its suitability for UWB optimisation routines.

Towards 1000-mode Optical Fibres

We report on the design of multimode-mode fibres guiding up to 870 spatial and polarization modes for low differential mode delay over the C-band.

On a Scalable Path for Multimode MIMO-DSP

A novel MIMO-DSP for space-division multiplexing over multimode fibres is proposed. A principal modes approach is shown to provide two-fold benefits: over 13 times channel memory reduction while minimising the number of optical front-ends needed to detect a subset of the spatial domain.