QoT Evaluation of Optical Line System Transmission with Bismuth-Doped Fiber Amplifiers in the E-Band

We numerically investigate E-band quality of the transmission using an ex- perimentally characterized bismuth-doped fiber amplifier, demonstrating its impact on de-ployed C+L system

Development of Bismuth-Doped Fibers (BDFs) in Optical Communication Systems

This chapter will provide background information in the development of BDFs and their applications in optical communication systems. Herein, the main focus is briefly described previous studies on BDFs that have attracted much interest over the last two decades. This necessary information and concepts are very much relevant to understanding this book, mainly due to the doping of Bi in the studied bismuth and erbium-doped silicate fibers (BEDFs). The remaining chapter is consisting of the following sections: Sec.2: General introduction about optical fibers. Sec. 3 discusses the general spectral characteristics of BDFs. Sec.4: Including the active centers (namely the bismuth (Bi) active centers (BACs)) responsible for the spectral properties in Bi-doped fibers. Sec.4 Discusses the Bismuth Doped Fiber Amplifier (BDFA)

Bismuth

Bismuth—a wonder metal with unique features—plays an important role in the bismuth-related optoelectronic materials. The innovative development of bismuth optoelectronic materials will undoubtedly drive the social development and economic growth in the world towards a glorious future

Devices and Fibers for Ultrawideband Optical Communications

Wavelength-division multiplexing (WDM) has historically enabled the increase in the capacity of optical systems by progressively populating the existing optical bandwidth of erbium-doped fiber amplifiers (EDFAs) in the C-band. Nowadays, the number of channels—needed in optical systems—is approaching the maximum capacity of standard C-band EDFAs. As a result, the industry worked on novel approaches, such as the use of multicore fibers, the extension of the available spectrum of the C-band EDFAs, and the development of transmission systems covering C- and L-bands and beyond. In the context of continuous traffic growth, ultrawideband (UWB) WDM transmission systems appear as a promising technology to leverage the bandwidth of already deployed optical fiber infrastructure and sustain the traffic demand for the years to come. Since the pioneering demonstrations of UWB transmission a few years ago, long strides have been taken toward UWB technologies. In this review article, we discuss how the most recent advances in the design and fabrication of enabling devices, such as lasers, amplifiers, optical switches, and modulators, have improved the performance of UWB systems, paving the way to turn research demonstrations into future products. In addition, we also report on the advances in UWB optical fibers, such as the recently introduced nested antiresonant nodeless fibers (NANFs), whose future implementations could potentially provide up to 300-nm-wide bandwidth at less than 0.2 dB/km loss

Bismuth-doped Fibre Amplifiers for Multi-band Optical Networks

Fibre-optic networks are the backbone of the global communications infrastructure that made possible modern Internet, providing a multitude of online services and a digital economy. The development of novel approaches for further increasing capacity of optical communication systems is in the focus of research around the world due to the constantly growing data traffic and the corresponding bandwidth demand. Arguably, the most practical technique is multi-band transmission which utilises a huge spectral bandwidth of the existing fibre base that has not previously been used. Unlike spatial division multiplexing, multi-band transmission does not require a new fibre deployment. However, it involves a significant upgrade of current networks with novel amplifiers in the O-, E-, S-, and U- optical bands that are yet to be developed and optimised. In this thesis, E- and S-band bismuth-doped fibre amplifiers (BDFAs) are demonstrated. The following record characteristics of BDFAs are achieved: 40 dB gain, 4.5 dB noise figure, and 38% power conversion efficiency. In total, three BDFAs have been developed, characterised and optimised using pump laser diodes at different wavelengths. Two modelling techniques of BDFAs are proposed: one based on conventional rate equations, and another one based on a neural network "black box" approach. Both of these methods are analysed and their challenges are discussed. A big part of the thesis is devoted to data transmission demonstrations supported by developed BDFAs in E- and S-bands. The experiments include both IM/DD and coherent signal transmissions through various lengths of single mode fibre including record E-band transmission through 160 km of single mode fibre. In addition, a multi-band transmission experiment in E-, S-, C-, and L-band is performed with an in-line amplifier based on combined bismuth-doped fibre and discrete Raman amplification. The total signal bandwidth is 195 nm and the total number of transmitted channels is 143. The obtained results pave the way towards commercial implementation of multi-band transmission enabled by BDFAs in E- and S- optical communication bands

Performance Evaluation of Raman Amplifiers in Fibre Optic Communication Systems

This thesis presents an overview of Raman amplifiers in fibre optic transmission systems. Detailed analysis of the nonlinear accumulated noise and relative intensity noise (RIN) induced penalties are evaluated in discrete and distributed Raman amplifiers. In addition to these the thesis also includes different architectures of Raman amplifiers enabling multiband transmission. The parametric dependency of fibre chromatic dispersion (CD) on the accumulated nonlinear noise in discrete Raman amplifiers (DRAs) was studied both theoretically and experimentally. Analytical modelling was performed over different fibre types that are widely used as a gain medium in DRAs. It was found that systems using Raman gain fibres with a positive value of CD induce lower accumulated nonlinear noise in comparison to systems using Raman gain fibres with a negative value of CD. The results obtained from the analytical model were then validated experimentally over a long-haul transmission system with DRAs as an inline amplifier using a recirculation loop. RIN-induced penalties in distributed Raman amplifiers (DiRAs) were experimentally studied in two standard single-mode fibre (SSMF) G.654.E©TXF and G.652.D with different pumping schemes. Signal RIN for G.654.E© TXF was found to be lower in comparison to its counterpart G.652.D. The impact of RIN on the short-haul system was validated using both the test fibres pumped in a forward-pumped distributed Raman. Similarly, backward and bidirectional pumping was performed over a long-haul transmission system using a recirculation loop. It was experimentally observed that RIN-induced transmission penalties for G.654.E are lower in comparison to G.652.D making it a better choice of SSMF type for distributed amplification. Experiments on novel architectures such as cascaded dual-stage and dual-band designs were demonstrated over a coherent transmission system with S-, C- and L-band signals. It was observed that the dual-stage design requires a guard band of ~10 nm to prevent overlapping of the pumps and signal, reducing the overall transmission capacity. In contrast, for dual-band design, no such guard band was required, but this benefit comes at a cost of the additional pump requirement increasing the overall amplifier power consumption. The performances of novel multistage Raman amplifier structures were also evaluated over the E-, S-, C- and L-band. Experimental studies were performed independently using DRAs only, hybrid bismuth-DRA and hybrid distributed-DRA. The E- and S-band signals were seen to have higher performance penalties in comparison to C- and L-band signals in the case of DRAs only and hybrid bismuth-DRA. In contrast, for the hybrid distributed-discrete design, the E-band signals were seen to have a similar penalty as C- and L-band signals

Nonlinear Interference Generation in Wideband and Disaggregated Optical Network Architectures

L'abstract è presente nell'allegato / the abstract is in the attachmen

Novel Specialty Optical Fibers and Applications

Novel Specialty Optical Fibers and Applications focuses on the latest developments in specialty fiber technology and its applications. The aim of this reprint is to provide an overview of specialty optical fibers in terms of their technological developments and applications. Contributions include:1. Specialty fibers composed of special materials for new functionalities and applications in new spectral windows.2. Hollow-core fiber-based applications.3. Functionalized fibers.4. Structurally engineered fibers.5. Specialty fibers for distributed fiber sensors.6. Specialty fibers for communications

Assessment on the Achievable Throughput of Multi-band ITU-T G.652.D Fiber Transmission Systems

Fiber-optic multi-band transmission (MBT) aims at exploiting the low-loss spectral windows of single-mode fibers (SMFs) for data transport, expanding by ∼11× the available bandwidth of C-band line systems and by ∼5× C+L-band line systems'. MBT offers a high potential for cost-efficient throughput upgrades of optical networks, even in absence of available dark-fibers, as it utilizes more efficiently the existing infrastructures. This represents the main advantage compared to approaches such as multi-mode/-core fibers or spatial division multiplexing. Furthermore, the industrial trend is clear: the first commercial C+L-band systems are entering the market and research has moved toward the neighboring S-band. This article discusses the potential and challenges of MBT covering the ITU-T optical bands O → L. MBT performance is assessed by addressing the generalized SNR (GSNR) including both the linear and non-linear fiber propagation effects. Non-linear fiber propagation is taken into account by computing the generated non-linear interference by using the generalized Gaussian-noise (GGN) model, which takes into account the interaction of non-linear fiber propagation with stimulated Raman scattering (SRS), and in general considers wavelength-dependent fiber parameters. For linear effects, we hypothesize typical components' figures and discussion on components' limitations, such as transceivers,' amplifiers' and filters' are not part of this work. We focus on assessing the transmission throughput that is realistic to achieve by using feasible multi-band components without specific optimizations and implementation discussion. So, results are meant to address the potential throughput scaling by turning-on excess fiber transmission bands. As transmission fiber, we focus exclusively on the ITU-T G.652.D, since it is the most widely deployed fiber type worldwide and the mostly suitable to multi-band transmission, thanks to its ultra-wide low-loss single-mode high-dispersion spectral region. Similar analyses could be carried out for other single-mode fiber types. We estimate a total single-fiber throughput of 450 Tb/s over a distance of 50 km and 220 Tb/s over regional distances of 600 km: ∼ 10 × and 8× more than C-band transmission respectively and ∼ 2.5× more than full C+L