Dense Wavelength Division Multiplexing Technique Research Articles

Integration of QKD Channels to Classical High-speed Optical Communication Networks

Integrating Quantum Key Distribution service with classical high-speed optical data transmission using a dense wavelength division multiplexing technique in a fiber is a cost-effective solution to improve the network's security. In this multichannel system, several noise sources degrade the quality of the quantum channel. The dominant degradation effect is determined by modeling in different cases. Optical filtering cannot decrease spontaneous Raman Scattering caused by the classical optical channels. So this nonlinear optical effect is investigated in detail with different system parameter setups. The optimal channel allocation and the required bandgap between the classical and quantum channels are determined.

Mitigating the Effect of Chromatic Dispersion in Shared Path Optical Network using Intelligent Dense Wavelength Division Multiplexing Techniques

Mitigating the Effect of Chromatic Dispersion in Shared Path Optical Network using Intelligent Dense Wavelength Division Multiplexing Techniques

Tunable In-series Laser Array With Duplex Distributed Feedback Sections

The tunable laser based on distributed feedback (DFB) laser array has a good single-longitudinal-mode property, high wavelength stability, narrow spectrum linewidth, and feasibility for monolithic integration. The tunable in-series DFB laser array (TIDLA) was proposed to avoid the large extra power loss by the optical combiner. But in the TIDLA, a large laser count will cause a large chip length, which brings about low utilization ratio of material, poor mechanical strength, and large power consumption. In this paper, we demonstrated a 4-channel TIDLA with duplex DFB sections. The total chip length was greatly shortened owing the duplexing of DFB sections. A long linearly chirped Bragg grating is implemented in the laser cavity to reduce the grating interference among different lasers. Multiple π phase shifts and two reflector sections are introduced to improve the mode stability. The designed channel spacing is 100 GHz, and the reconstruction-equivalent-chirp technique is used to provide high precision control of the grating phase. Noted that a variation of 0.1 nm in grating period will cause that of 0.65 nm in wavelength. Output power of above 4 mW, SMSR of above 42 dB, and small wavelength deviation of within 0.15 nm was obtained. Besides, fast channel switches of less than 1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s are obtained by laser on/off switching. The proposed TIDLA might be applied in the NG-PON2 network where the dense wavelength division multiplexing technique and fast channel switching are required.

Performance analysis and selection of wavelength channels based on the FWM effect influence in optical DWDM systems

A deployment of the Dense Wavelength Division Multiplexing (DWDM) in long-haul and metropolitan networks is becoming a reality, its extensive operation is also expected in future next-generation passive optical networks in a short time. This paper is focused on the DWDM technique and its effective utilization in real optical systems and networks. Within this context, an attention is paid to the Four Wave Mixing (FWM) effect that presents the most prominent nonlinearity that can limit the available transmission capacity in the given optical DWDM system. A realized simulation model of the 15-channel DWDM system that can exactly analyze the FWM influence on transmitted wavelength channels in the optical transmission path is presented. Based on executed performance analyses of the FWM influence, possibilities for selection of wavelength channels suitable for practical utilization in the DWDM communication system are introduced.

60 Gbps 4-PAM VCSEL-based Raman assisted hyper-scale data centre: In context of spectral efficiency and reach extension

Abstract Cost effective large-scale installation of hyper-scale data centres has attracted extensive research recently, due to the exponential bandwidth demand over extended reach. Low cost, power and spectral efficient techniques for increasing network capacity, as well as extending the transmission reach while maintaining duplex connectivity are still key challenges facing current big data networks such as hyper-scale data centre networks. In this work, a low cost energy efficient technique for maximizing carrier spectral efficiency and extending transmission reach is experimentally demonstrated. This is achieved through combined adoption of vertical cavity surface emitting lasers (VCSELs), four level pulse amplitude modulation (4-PAM), dense wavelength division multiplexing (DWDM) and Raman amplification. Three class 10 G VCSEL channels are directly modulated with a 20 Gbps 4-PAM data signal therefore maximizing carrier spectral efficiency by doubling the data rate per channel. The channels are then converged to a single fibre link through DWDM technique at 0.4 nm spacing, achieving a total aggregated data rate of 60 (3 × 20) Gbps. By exploiting the 8.6 dB flat gain of a forward Raman pump, a 77.12 km of standard single mode fibre (SMF) transmission is experimentally achieved. To the best of our knowledge, this is the longest error free fibre transmission distance reported using VCSEL-based 60 Gbps 4-PAM, without any forward error correction (FEC), equalization and pre-emphasis mechanisms. Results show that a real time uncorrected BER

Methodology for evaluating linear and non-linear effects in a radio over fiber system

This article shows the methodology used to evaluate the linear and non-linear effects present in a radio over fiber system (RoF) by employing the multiplexing technique used for dense wave division, the Dense Wavelength Division Multiplexing (DWDM) technique. It is completed with a dissemination of 50 GHz, in accordance to the standards of the International Telecommunication Union (ITU), through a channel speed of 10 Gbps, at an input power in the optical channel of 30mW, for optical fiber stretches of 40km, 60km and 80km. It presents the modeling of the RoF system graphically through a block diagram by means Matlab, a computational tool, whereby each of the stages of the RoF system are implemented using the libraries offered by the ‘simulink’ toolbox of Matlab. As a result, it is obtained that the methodology proposed for the evaluation of the RoF system using the DWDM technique allows for the analysis of linear and non-linear effects; where it is observed that the effects that degrade the signal are proportional to the established distances of the optical fiber and that the optical input power used is optimal for the optical fiber to behave as a non-linear medium.

Characterization of the electro-optical transceivers in the KM3NeT optical network

KM3NeT is a future research infrastructure hosting a network of neutrino telescopes in the abyss of the Mediterranean Sea. The whole data transport over an optical network is based on the Dense Wavelength Division Multiplexing technique with optical channels spaced 50 GHz apart and a bit rate of 1.25 Gbps. Over the telescope lifetime, precise temperature control of the laser is required to maintain stability of the central frequency, complying with the recommendations of the International Telecommunication Union. We will report on the characterisation of the tuneable features of the electro-optical transceivers required to compensate for the expected wavelength drift due to aging factors. Preliminary results will be showed.