The rising demand for transmission capacity in optical networks has motivated steady interest in expansion beyond the standard C-band (1530-1565 nm) into the adjacent L-band (1565-1625 nm), for an approximate doubling of capacity in a single stroke. However, in the context of quantum networking, the ability to leverage the L-band will require advanced tools for characterization and management of entanglement resources which have so far been lagging. In this work, we demonstrate an ultrabroadband two-photon source integrating both C- and L-band wavelength-selective switches for complete control of spectral routing and allocation across 7.5 THz in a single setup. Polarization state tomography of all 150 pairs of 25 GHz-wide channels reveals an average fidelity of 0.98 and total distillable entanglement greater than 181 kebits/s. This source is explicitly designed for flex-grid optical networks and can facilitate optimal utilization of entanglement resources across the full C+L-band.
@article{arxiv.2207.08909,
title = {Broadband polarization-entangled source for C+L-band flex-grid quantum networks},
author = {Muneer Alshowkan and Joseph M. Lukens and Hsuan-Hao Lu and Brian T. Kirby and Brian P. Williams and Warren P. Grice and Nicholas A. Peters},
journal= {arXiv preprint arXiv:2207.08909},
year = {2022}
}