Towards an Optimal Photonic Network: Optimising Performance, Cost and Flexibility

This thesis investigates optical fibre transmission system technologies, and their impact on network architectures with the objective of lowering unit cost ($/Gb/s/km) of data transmission in long-haul, and ultra long-haul dense wavelength division multiplexing (DWDM) photonic networks. The importance of this work is driven by the exponential growth in Internet traffic of around 40% p.a., and economic pressures constraining network operators’ ability to invest in their networks. Optical transport networks must therefore be designed to meet future bandwidth demands of end users, with optimum performance, cost and flexibility. Dynamic gain equalisers (DGEs) are a key sub-system of ultra long-haul networks, enabling increased un-regenerated transmission reach and elimination of expensive optical-electrical-optical (OEO) regeneration. A theoretical framework was developed integrating models of wideband power variation, together with narrowband nonlinear propagation simulations using the split-step Fourier method. The optimum spacing of the also costly DGEs was determined for a 3,000km network field deployment. Optimum power pre-emphasis profiles were predicted and compared with simple linear calculations, showing <0.7dB performance penalty using the much faster, simplified method. Optical dispersion management schemes were studied, with optical dispersion compensating fibre placed after every other span resulting in 6% cost reduction and little performance degradation compared to compensation after every span. A techno-economic comparison of optical and electronic dispersion compensation (EDC) strategies showed 25% cost reduction using EDC. Tolerance to fibre nonlinearities is reduced compared to optical compensation; splitting the EDC function equally between transmitter and receiver optimises performance. Economic benefits of a single flexible, multi-reach DWDM system were investigated showing almost 20% cost savings compared to separate long-haul and ultra long-haul systems. Finally, the techno-economic benefits of optical bypass in meshed networks were analysed for increasing levels of optical transparency: from OEO regenerated to multi-degree reconfigurable optical add-drop multiplexers (MD-ROADMs), enabling up to 46% cost saving

Analisis Perbandingan Kinerja Pengkodean Kanal Non-Return-to-Zero (NRZ) dan Return-to-Zero (RZ) pada Rancangan Jaringan Long-haul Dense Wavelength Division Multiplexing (DWDM)

Abstrak Perkembangan jangkauan dan penggunaan internet mendorong pengembangan penyediaan layanan dengan transmisi data yang cepat dan kapasitas yang besar seperti layanan berbasis serat optik. Jaringan long-haul DWDM sebagai teknologi multipleksing sangat mendukung proses transmisi optik jarak jauh. Performa media transmisi long-haul DWDM membutuhkan teknik pengkodean kanal yang dapat diimplementasikan pada sisi pengirim agar diperoleh sistem yang efisien dalam hal bandwidth transmisi. Dalam komunikasi serat optik terdapat beberapa jenis teknik pengkodean kanal yang umum digunakan seperti non-return-to-zero (NRZ) dan return-to-zero (RZ). Penelitian ini bertujuan untuk membandingkan kinerja rancangan sistem dengan variasi teknik pengkodean dengan memberikan variasi daya pancar laser sebesar 0, 2, 4, 6, dan 8 dBm dan variasi jarak sebesar 200, 400, 600, 800, dan 1000 km. Rancangan sistem menggunakan modulasi eksternal dan NRZ atau RZ pada sisi transmitter, serat optik dan penguat EDFA pada media transmisi, dan detektor optik pada sisi receiver. Berdasarkan hasil penelitian, tidak semua kanal sesuai dengan hasil Q-factor dan BER berdasarkan standar ITU-T, namun jenis pengkodean kanal NRZ lebih baik digunakan pada jenis jaringan long-haul DWDM. Abstract The increasing of coverage area and demand for internet services are both drive the development of providing services with high bitrate transmission and gigantic capacity, such as fiber optic communication. Long-haul DWDM network as a multiplexing technology is very supportive in the long-distance optical transmission link requiring channel coding which can be implemented in transmitter. There are various types of channel coding used in optical fiber communication, such as non-return-to-zero and return-to-zero. The aims of this work are to compare the system performance with different channel coding in long-haul link using variations of optical power launch with value 0, 2, 4, 6, and 8 dBm and variations of length of link with value 200, 400, 600, 800, and 1000 km. The design system uses external modulation and NRZ or RZ on the transmitter, optical Fiber with EDFA amplifier on the optical transmission, and optical detector on the receiver. Based on the results, there are several channels with the Q-factor and BER that do not meet the ITU standards. In addition, the NRZ channel coding is better used in the long-haul DWDM link

High Data Rate Coherent Optical OFDM System for Long-Haul Transmission

The growth in internet traffic has driven the increase in demand for bandwidth and high data rates. Optical Orthogonal Frequency Division Multiplexing is considered as a promising technology to satisfy the increased demand for bandwidth in broadband services. Optical OFDM received a great attention after proposing it as a modulation technique for the long-haul transmission in both direct and coherent detection. However, Coherent Optical OFDM (CO-OFDM) is the next generation technology for the optical communications, since it integrates the advantages of both coherent systems and OFDM systems. It has the ability to overcome many optical fiber restrictions such as chromatic dispersion (CD) and polarization mode dispersion (PMD). Moreover, Integrating the Coherent Optical OFDM with Wavelength Division Multiplexing (WDM) systems will provide the transmission system with a high bandwidth, a significant data rates, and a high spectral efficiency without increasing the cost or the complexity of the system. WDM systems help to enhance the capacity and the data rate of the system by sending multiple wavelengths over a single fiber. This research focuses on the implementation and performance analysis of high data rate coherent optical OFDM for long-haul transmission. The study starts with a single user and extends to the implanting of the WDM system. OptiSystem-12 simulation tool is fully used to design and implement the system. The system utilizes to carry range of data rates start from 10 Gbps to 1 Tbps, 4-QAM (2 bits-per-symbol) is used a modulation type for the OFDM signal, Optical I/Q modulation is employed at the transmitter and coherent detection is employed at the receiver. The performance of the system is studied and analyzed system in terms of Bit-Error-Rate (BER), the effect of the transmission distance on the Optical-Signal-to-Noise-Ratio (OSNR), and the relation of BER and OSNR with regard to the transmission distance

Harnessing machine learning for fiber-induced nonlinearity mitigation in long-haul coherent optical OFDM

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Coherent optical orthogonal frequency division multiplexing (CO-OFDM) has attracted a lot of interest in optical fiber communications due to its simplified digital signal processing (DSP) units, high spectral-efficiency, flexibility, and tolerance to linear impairments. However, CO-OFDM’s high peak-to-average power ratio imposes high vulnerability to fiber-induced non-linearities. DSP-based machine learning has been considered as a promising approach for fiber non-linearity compensation without sacrificing computational complexity. In this paper, we review the existing machine learning approaches for CO-OFDM in a common framework and review the progress in this area with a focus on practical aspects and comparison with benchmark DSP solutions.Peer reviewe

Digital Signal Processing for Optical Communications and Networks

The achievable information rates of optical communication networks have been widely increased over the past four decades with the introduction and development of optical amplifiers, coherent detection, advanced modulation formats, and digital signal processing techniques. These developments promoted the revolution of optical communication systems and the growth of Internet, towards the direction of high-capacity and long-distance transmissions. The performance of long-haul high-capacity optical fiber communication systems is significantly degraded by transmission impairments, such as chromatic dispersion, polarization mode dispersion, laser phase noise and Kerr fiber nonlinearities. With the entire capture of the amplitude and phase of the signals using coherent optical detection, the powerful compensation and effective mitigation of the transmission impairments can be implemented using the digital signal processing in electrical domain. This becomes one of the most promising techniques for next-generation optical communication networks to achieve a performance close to the Shannon capacity limit. This chapter will focus on the introduction and investigation of digital signal processing employed for channel impairments compensation based on the coherent detection of optical signals, to provide a roadmap for the design and implementation of real-time optical fiber communication systems

Design and simulation of 1.28 Tbps dense wavelength division multiplex system suitable for long haul backbone

Wavelength division multiplex (WDM) system with on / off keying (OOK) modulation and direct detection (DD) is generally simple to implement, less expensive and energy efficient. The determination of the possible design capacity limit, in terms of the bit rate-distance product in WDM-OOK-DD systems is therefore crucial, considering transmitter / receiver simplicity, as well as energy and cost efficiency. A 32-channel wavelength division multiplex system is designed and simulated over 1000 km fiber length using Optsim commercial simulation software. The standard channel spacing of 0.4 nm was used in the C-band range from 1.5436-1.556 nm. Each channel used the simple non return to zero - on / off keying (NRZ-OOK) modulation format to modulate a continuous wave (CW) laser source at 40 Gbps using an external modulator, while the receiver uses a DD scheme. It is proposed that the design will be suitable for long haul mobile backbone in a national network, since up to 1.28 Tbps data rates can be transmitted over 1000 km. A bit rate-length product of 1.28 Pbps.km was obtained as the optimum capacity limit in 32 channel dispersion managed WDM-OOK-DD system.Comment: Accepted for publication in Journal of Optical Communications - De Gruyte

Sustainable economic development : concept, principles and management from Islamic perspective

The basic concern of development in Islamic economic system is on human welfare. This is in line with the very basic objective of Islamic jurisprudence (Shari’ah ) which puts important to the welfare of the people and their relief from hardship. Economic development should be consistent with this central objective of shari`ah. The center for development process in Islam relies on man as an economic agent. It is man to be educated on the entire development process by integrating sosial development, economic development and environmental conservation and protection. This paper attempts to explain the concept, principles and management of sustainable economic development from Islamic perspective. The paper would start by defining the concept of sustainable economic development and development goals. Next, the Islamic principles for sustainable economic development would be discussed, followed by the discussion on the management of sustainable economic development from Islamic perspective. In conclusion, the paper strongly suggests the economic development process to fully adhere to the Islamic principles as the key for sustainable development which covers both the material and non-material aspects of life. Keywords: Sustainable development, Economic development, management, Islamic economics, economic syste