Highly Efficient Multi-Band Optical Networks with Wavelength-Selective Band Switching

Abstract

Multi-band transmission technologies promise to costeffectively expand the capacity of optical networks by exploiting low-loss spectrum windows beyond the conventional band used in already-deployed fibers. While such technologies offer a high potential for capacity upgrades, available capacity is seriously restricted not only by the wavelengthcontinuity constraint but also by the signal-to-noise ratio (SNR) constraint. In fact, exploiting more bands can cause higher SNR imbalance over multiple bands, which is mainly due to stimulated Raman scattering. To relax these constraints, we propose wavelength-selective band switchingenabled networks (BSNs), where each wavelength channel can be freely switched to any band and in any direction at any optical node on the route. We also present two typical optical node configurations utilizing all-optical wavelength converters, which can realize the switching proposal. Moreover, numerical analyses clarify that our BSN can reduce the fiber resource requirements by more than 20% compared to a conventional multi-band network under realistic conditions. We also discuss the impact of physicallayer performance of band switching operations on available benefits to investigate the feasibility of BSNs. In addition, we report on a proof-ofconcept demonstration of a BSN with a prototype node, where C+L-band wavelength-division-multiplexed 112-Gb/s dual-polarization quadrature phase-shift keying signals are successfully transmitted while the bands of individual channels are switched node-by-node for up to 4 cascaded nodes.

Low-Penalty Band-Switchable Multi-Band Optical Cross-Connect Using PPLN-Based Inter-Band Wavelength Converters

“…A. Benefit MB transmission with band switching in OXCs enables a significant increase in the traffic volume that can be accommodated [6], [7]. It is assumed that individual wavelength channels can be switched to any band and any direction at any node on the route.…”

“…In MB networks, optical node systems that can efficiently Haruka Minami, Kenta Hirose, Takafumi Fukatani, Masahiro Nakagawa, Takeshi Seki, and Takeshi Kuwahara are with NTT Network Service Systems Labs., NTT Corporation, Musashino-shi, 180-8585, Japan (e-mail: haruka.minami@ntt.com; kenta.hirose@ntt.com; takafumi.fukatani@ntt.com; mshr.nakagawa@ntt.com; takeshi.seki@ntt.com; takeshi.kuwahara@ntt.com) utilize wavelength resources are desirable. We have proposed a multi-band optical cross-connect (MB-OXC) that can switch not only the output direction but also the output wavelength band of the input signals [5]- [7]. MB transmissions with the band switching enables a significant increase in the traffic volume that can be accommodated in networks.…”

“…The AO-WC is capable of simultaneous wavelength conversion of multiple WDM channels between different transmission bands. This feature, which is not found in conventional opticalelectrical-optical wavelength converters, results in lower costs and energy consumption [7], [8]. So far, we have demonstrated a band-switchable C+L-band OXC supporting 112-Gbit/s/λ DP-QPSK signal transmission using highly-nonlinear-fiber-(HNLF-) based AO-WCs [5].…”

Análise de Desempenho de Estratégias de Alocação de Banda em uma Rede Óptica Elástica Multibanda

“…Na literatura, observam-se estratégias de alocação de banda em redes ópticas MB que utilizam atribuições fixas [2]- [4], [7]- [9], heurísticas [10]- [13] e técnicas de inteligência artificial [6], [14], [15]. Além disso, algumas consideram penalidades físicas por meio de modelagens analíticas [2]- [4], [9], [13] e outras por meio do alcance máximo [6], [7], [10], [11], [14], [15].…”

“…Para cada rota, a heurística proposta listava primeiro todas as combinações de banda possíveis para cada enlace, estimava o valor da relação sinal-ruído generalizada (GSNR -Generalized Signal-to-Noise Ratio) para cada uma delas e, em seguida, selecionava a que possuía o valor da margem de GSNR mais baixa possível. Foram consideradas ainda as bandas S, C e L. Em [13], Nakagawa et al propuseram o conceito de redes habilitadas para comutação de banda com base no comprimento de onda, onde cada comprimento de onda poderia ser comutado para qualquer banda e em qualquer nó. Os autores apresentaram também duas arquiteturas de nó óptico utilizando conversores de comprimento de onda totalmente ópticos.…”