Lidia Galdino

We propose a GSNR-based fiber figure of merit and closed-form expressions for estimating the span length or attenuation required for different fibers to achieve equal transmission capacity under the large-span-loss approximation. It enables accurate fiber comparison and supports transmission system design for practical greenfield deployments.

We present an experimental demonstration of full C+L-band 2-core fiber transmission over 114.6 km × 5 spans. The span length of 114.6 km is the longest span reported for weakly-coupled multicore fibers (MCFs), which enables cost-effective MCF systems by reducing amplifier-related costs. To achieve a long-span MCF system, we develop ultra-low-loss fan-in/fan-out devices with a minimum insertion loss of 0.20 dB, and utilize ultra-low-loss 2-core fiber with an average loss of 0.149 dB/km. In the transmission, all the 740 channels with 24-Gbaud 16-quadrature amplitude modulation have sufficient Q$^{2}$-factors $>$6.5 dB, corresponding to a total capacity of 126 Tb/s. Through experimental and theoretical investigations, we clarify that the degradation of the Q$^{2}$-factors due to inter-core crosstalk is less than 0.30 dB, and that amplified spontaneous emission noise added by amplifiers mainly limits the transmission performance.

Homogeneous performance in long-haul wideband transmission systems can be challenging to achieve, as fundamental effects such as stimulated Raman scattering, Raman and EDFA gain ripple and band-specific component limitations contribute to spectrally non-uniform and co-dependent penalties. In this work we focus on the system design trade-offs needed to transmit 800 Gb/s error-free channels on every transponder across the entirety of a 9.6 THz C+L line system. The combination of hybrid Raman-EDFA amplification, high performance G.654.E fiber, digital-twin-based inter-band power optimization, and per-channel power emphasis allow the transmission of an aggregate 72 Tb/s over 1504 km using real-time 100.4 GBd digital subcarrier-based elastic optical transponders. This is, to the best of our knowledge, the highest real-time capacity-distance product of any multi-band system demonstrated to date, and the first real-time multi-band demonstration to sustain a spectral efficiency greater than 7 b/s/Hz over long-haul distances.

Space Division Multiplexing using multicore optical fibers (MCF) is emerging as a promising technology for achieving capacity in excess of 1 Pb/s for submarine transmission systems. In this paper, we discuss the key MCF design considerations that result in transmission performance comparable to a single core fiber in submarine transmission systems. Based on these considerations, uncoupled 2-core multicore fibers having two different core-designs were designed with Effective Area of 112 mm2 at 1550 nm. These designs were fabricated and record attenuation of 0.1444 dB/km and 0.1449 dB/km are reported for lowest attenuation core for each design, with attenuation of 0.1457 dB/km and 0.1455 dB/km at 1550nm. This was enabled by using silica-core technology, along with improvements in core-processing and mitigation of attenuation contributors in the fiber manufacturing, including optimization of the draw conditions. Sensitivity of fiber attenuation (including radiation loss to high index coating) and copropagating and counterpropagating crosstalk to inter-core distance is studied and reported. Heterogeneous core MCF designs are evaluated for achieving good crosstalk performance even in cables where the bend radius encountered by the fiber is significantly larger than the bend radius on a shipping spool. Heterogeneous core MCFs where different core radius is used for core identification are also attractive for elimination of marker cores. ©2023 The Author(s)

A closed-form model for the nonlinear interference (NLI) in Raman amplified links is presented, the formula accounts for both forward (FW) and backward (BW) pumping schemes and inter-channel stimulated Raman scattering (ISRS) effect. The formula also accounts for an arbitrary number of pumps, wavelength-dependent fibre parameters, launch-power profiles, and is tested over a distributed Raman-amplified system setup. The formula is suitable for ultra-wideband (UWB) optical transmission systems and is applied in a signal with 13 THz optical bandwidth corresponding to transmission over the S-, C-, and L- band. The accuracy of the closed-form formula is validated through comparison with numerical integration of the Gaussian noise (GN) model and split-step Fourier method (SSFM) simulations in a point-to-point transmission link.

The performance of a wideband coherent receiver was investigated. The relative impact of digital pre-distortion, geometric constellation shaping and pilot sequence detection, as well as the number of sub-channels in the super-channel, on the receiver performance was explored. The detection of a net data rate of 2.36 Tb/s after 75 km transmission of 8 × 26 GBd DP-GS-256-QAM super-channels was demonstrated using a single 110-GHz electrical bandwidth receiver. The overall improvement due to the digital pre-distortion and tailored geometric constellation shaping was 1.2 bit/4D-sym in the achievable information rate.

A closed-form formula for the nonlinear interference (NLI) estimation using the Gaussian noise (GN) model in the presence of inter-channel stimulated Raman scattering (ISRS) is derived. The formula enables accurate estimation of the NLI evolution along any portion of the fibre span together with arbitrary values of optical fibre losses. The formula also accounts for wavelength-dependent fibre parameters, variable modulation formats and launch power profiles. The formula is suitable for ultra-wideband (UWB) optical transmission systems and its accuracy is assessed for a system with 20 THz optical bandwidth over the entire S-, C-, and L- band through comparison with numerical integration of the ISRS GN model and split-step Fourier method (SSFM) simulations in point-to-point transmission and inline NLI estimation scenarios.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.