scholarly journals Performance Analysis of Crosstalk Subcarrier Multiplexing and Wave Division Multiplexing in Optical Communication System

Author(s):  
Ebrahim E. Elsayed

Abstract In traditional optical communication, duplexity is achieved by using two fibers, each having a transmitter and a receiver. Economically, bidirectional wavelength division multiplexing (WDM) transmission systems utilizing a single fiber will be more attractive not only reducing the use of the fiber by a factor of two, but also the number of components. Duplex transmissions over a single fiber can double the capacity of an installed unidirectional link. The idea of this paper is to study another approach using the subcarrier multiplexing (SCM)-based optical network and evaluate the physical transmission quality of analog and digital signal using SCM approach and the characteristic of fiber nonlinear crosstalk such as stimulated Raman scattering, Cross phase modulation and four-wave mixing in the SCM externally modulation optical link. A suitable bandwidth of 890 – 950 MHz is selected for subcarriers and channel bandwidth of 200 KHz and carrier. By measuring the optical bit interference (OBI) performance limitations of the subcarrier multiplexing WDM optical transmission system is investigated. The OBI for 10 channels for input power 1 dB is -40 dB whereas for 110 channels the OBI is -20 dB separation of 250 KHz are considered.

2021 ◽  
Author(s):  
Ebrahim E. Elsayed

Abstract In traditional optical communication, duplexity is achieved by using two fibers, each having a transmitter and a receiver. Economically, bidirectional wavelength division multiplexing (WDM) transmission systems utilizing a single fiber will be more attractive not only reducing the use of the fiber by a factor of two, but also the number of components. Duplex transmissions over a single fiber can double the capacity of an installed unidirectional link. The idea of this paper is to study another approach using the subcarrier multiplexing (SCM)-based optical network and evaluate the physical transmission quality of analog and digital signal using SCM approach and the characteristic of fiber nonlinear crosstalk such as stimulated Raman scattering, Cross phase modulation and four-wave mixing in the SCM externally modulation optical link. A suitable bandwidth of 890 – 950 MHz is selected for subcarriers and channel bandwidth of 200 KHz and carrier. By measuring the optical bit interference (OBI) performance limitations of the subcarrier multiplexing WDM optical transmission system is investigated. The OBI for 10 channels for input power 1 dB is -40 dB whereas for 110 channels the OBI is -20 dB separation of 250 KHz are considered.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Meet Kumari ◽  
Reecha Sharma ◽  
Anu Sheetal

AbstractNowadays, bandwidth demand is enormously increasing, that causes the existing passive optical network (PON) to become the future optical access network. In this paper, next generation passive optical network 2 (NG-PON2) based, optical time division multiplexing passive optical network (OTDM-PON), wavelength division multiplexing passive optical network (WDM-PON) and time & wavelength division multiplexing passive optical network (TWDM-PON) systems with 20 Gbps (8 × 2.5 Gbps) downstream and 20 Gbps (8 × 2.5 Gbps) upstream capacity for eight optical network units has been proposed. The performance has been compared by varying the input power (−6 to 27 dBm) and transmission distance (10–130 km) in terms of Q-factor and optical received power in the presence of fiber noise and non-linearities. It has been observed that TWDM-PON outperforms OTDM-PON and WDM-PON for high input power and data rate (20/20 Gbps). Also, TWDM-PON shows its superiority for long-reach transmission up to 130 km, which is a cost-effective solution for future NG-PON2 applications.


Author(s):  
N. S.C. Correia ◽  
M. C.R. Medeiros

The telecommunications world is evolving dramatically toward challenging scenarios where the fast and efficient transportation of information is becoming a key element in today’s society. Wavelength division multiplexing (WDM) technology has the potential to satisfy the ever-increasing bandwidth needs of the network users on a sustained basis (Mukherjee, 2000). Network operators must provide uninterrupted service to their customers, that is, network survivability must be guaranteed. This means that, networks must be able to handle link or fiber cuts as well as equipment failures, fact that influences the design and operation of networks (Gerstel & Ramaswami, 2000). When using WDM, survivability becomes even more important because of the huge amount of traffic carried by a single fiber. A single fiber failure, even for few seconds, can be catastrophic (Maier, Pattavina, Patre & Martinelli, 2002). This issue is actually very important since the optical WDM technology is now being deployed in the field. Network survivability is not just an academic subject. In real networks, failures happen quite frequently (fiber cuts, for example, are very common in terrestrial networks since they share other utility transport conduits, such as gas or water pipes and electrical cables, and are considered the least reliable component (Gerstel & Ramaswami, 2000; Maier, Pattavina, Patre & Martinelli, 2002). The prevention of service interruption, or the reduction of the service loss when failures occur, must now be an integral part of the network design and operations strategy or otherwise severe service losses can happen.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Md. Harun Ar Rashid ◽  
Subrata Sikder ◽  
Kazi Farhan Sadik ◽  
S.H. Shah Newaz ◽  
Kazi Towfiqul Islam Jayner ◽  
...  

Abstract We demonstrate the design and simulation of a long range four-channel wavelength division multiplexing-passive optical network (WDM-PON) operating at 40 Gb/s (4 × 10 Gb/s) in downstream transmission for undersea wireless optical communication. The proposed model consists of two separate subsections between the optical transmitter and receiver. The first subsection consists of the central office and 50 km long feeder fiber for transmitting the optical signal from a distant base station to the 1 × 4 optical demultiplexer located at the sea shore. The second subsection comprises 500 m distributed fiber from the 1 × 4 optical demultiplexer to the terminal point placed at the bottom of the sea and 15–20 m optical wireless channel inside sea water. Simulation results confirmed successful transmission of optical signals from the 50 km distant optical transmitter to the optical receiver located maximum 15 m inside the sea water with a signal-to-noise ratio of ∼20.96 dB, bit error rate of ∼1.55 × 10−8, and quality factor of ∼5.584. The eye diagram at the receiving end also exemplifies quality downstream data transmission at a rate of 10 Gb/s per channel. In addition, we compare the simulation results of the four-channel 40 Gb/s WDM-PON system with a four-channel WDM-PON system operating at 4 Gb/s (4 × 1 Gb/s). Simulation results confirm maximum reach of 17.5 m inside sea water at a cost of significant reduction in data rate. Furthermore, we analyze the system availability of the proposed WDM-PONs and find convincing results for high-speed secured data transmission under water.


Author(s):  
N. S.C. Correia

The telecommunications world is evolving dramatically toward challenging scenarios where the fast and efficient transportation of information is becoming a key element in today’s society. Wavelength division multiplexing (WDM) technology has the potential to satisfy the ever-increasing bandwidth needs of the network users on a sustained basis (Mukherjee, 2000). Network operators must provide uninterrupted service to their customers, that is, network survivability must be guaranteed. This means that networks must be able to handle link or fiber cuts as well as equipment failures, fact that influences the design and operation of networks (Gerstel & Ramaswami, 2000). When using WDM, survivability becomes even more important because of the huge amount of traffic carried by a single fiber. A single fiber failure, even for few seconds, can be catastrophic (Maier, Pattavina, Patre, & Martinelli, 2002). This issue is actually very important since the optical WDM technology is now being deployed in the field. Network survivability is not just an academic subject. In real networks, failures happen quite frequently (fiber cuts, for example, are very common in terrestrial networks since they share other utility transport conduits such as gas or water pipes and electrical cables, and are considered the least reliable component (Gerstel et al., 2000; Maier et al., 2002). The prevention of service interruption, or the reduction of the service loss when failures occur, must now be an integral part of the network design and operations strategy or otherwise severe service losses can happen.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed

AbstractThe 16-channels dense wavelength division multiplexing (DWDM) systems have been optimized by utilizing hybrid configurations of conventional optical fiber amplifiers (EDFA, RAMAN and SOA) and optical photodetectors (PIN, APD(Si) and APD(InGaAs)). The DWDM systems were implemented for 5 Gb/s channel speed using one of these configurations with 100 GHz channel spacing and 25 km amplifying section. The hybrid configurations are the combinations of (PIN + EDFA), (PIN + RAMAN), (PIN + SOA), (APD(Si) + EDFA), (APD(Si) + RAMAN), (APD(Si) + SOA), (APD(InGaAs) + EDFA), (APD(InGaAs) + RAMAN) and (APD(InGaAs) + SOA). Based on BER, Q-factor and eye diagrams, the performance was compared for these configurations under influences of various thermal noise levels of photodetectors over different fiber lengths ranging from 25 km up to 150 km. The results revealed that both APD structures give optimum performance at input power Pin = 5 dBm due to high internal avalanche gain. EDFA outperforms RAMAN and SOA amplifiers. SOA amplifier shows degraded performance because of nonlinearity effects induced. RAMAN amplifier seems to be the best alternative for long reach DWDM systems because it minimizes the effects of fiber nonlinearities. The configuration (APD(Si) + EDFA) is the most efficient and recommended to be used for transmission distance beyond 100 km due to its larger Q-factor.


2021 ◽  
Author(s):  
Sinan M. Abdulsatar ◽  
Mohammed A. Saleh ◽  
Abadulla Abass ◽  
M. H. Ali ◽  
Mohammed Ali Yaseen

Abstract The simulation and investigation of a 32×10 Gb/s WDM all–optical bidirectional hybrid communication system for outdoor applications is presented in this article via multidisciplinary softwares. In order to track the system condition, a strain sensor based on fiber Bragg grating (FBG) is integrated in–line with the fiber optic link (FO–link). Then, a free space optical link (FSO–link) with 4–channel is simulated to act backup or rescue to the FO–link in the event of disaster or bombing. The FO–link is working well until the strain reach to 180 µε, after that the FO–link has degraded. Therefore, an optical switch is incorporated in between these systems (FO–link & FSO–link) to turn–on the FSO–link which act as a backup system to FO–link and maintains the continuity of the data transmission. According to the hybrid link results, there is an efficient enhancement in the Q–factor as compared with the FO–link even when there is heavy rain.


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