Design of Optical I/Q Modulator Using Dual-drive Mach-Zehnder Modulators in Coherent Optical-OFDM System

2018 ◽  
Vol 39 (2) ◽  
pp. 155-159 ◽  
Author(s):  
Monika Nehra ◽  
Deepak Kedia
Keyword(s):  
High Speed ◽  
Dispersion Compensation ◽  
Optical Power ◽  
Optical Spectra ◽  
Coherent Detection ◽  
High Rate ◽  
Q Factor ◽  
Ofdm System ◽  
Optical Ofdm ◽  
Simulation Results

AbstractA CO-OFDM system combines the advantages of both coherent detection and OFDM modulation for future high speed fiber transmission. In this paper, we propose an I/Q modulation technique using dual-drive MZMs for high rate 10 Gb/s CO-OFDM system. The proposed modulator provides 10.63 dBm improved optical spectra compared to a single dual-drive MZM. The simulation results in terms of BER and Q factor are quite satisfactory upto a transmission reach of 3,000 km and that to without making use of any dispersion compensation. A BER of about 8.03×10−10and 15.06 dB Q factor have been achieved at −10.43 dBm received optical power.

scholarly journals Optical Back-Propagation for Nonlinear Compensation in OFDM-Based Long Range-Passive Optical Networks

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Ngo Thi Thu Trang ◽  
Nguyen Duc Nhan ◽  
Bui Trung Hieu
Keyword(s):  
Optical Networks ◽  
Long Range ◽  
Direct Detection ◽  
Back Propagation ◽  
Fourier Method ◽  
High Rate ◽  
Passive Optical Networks ◽  
Ofdm System ◽  
Nonlinear Compensation ◽  
Optical Ofdm

In direct-detection optical OFDM system, the nonlinear impairment is the key factor that limits the system performance. The back-propagation techniques in digital and optical domains have been proposed to compensate the nonlinear effects, however they can be unsuitable for long-range passive optical networks (LR-PONs) due to their implementation at receiver. In this study, we propose an optical back propagation (OBP) approach for compensation of the nonlinear and dispersion distortions in direct-detection optical OFDM system. The proposed OBP using split-step Fourier method is implemented at transmitter that is suitable for high-rate OFDM-based LR-PONs applications. In this OBP, the fiber Bragg grating (FBG) is used as a step for dispersion compensation and the high-nonlinear fiber (HNLF) with a short length is used as a step for nonlinear compensation. The performance improvement based on our proposed approach has been demonstrated via Monte-Carlo simulations of the 100 Gbit/s direct-detection optical OFDM system with 80 km of standard single mode fiber link. The influence of optical conjugation process and launching conditions has been investigated. The obtained results show that the proposed OBP can improve remarkably the performance of system with the launched power range from -2 dBm to 6 dBm.

An Improved Algorithm Based on Optimized PTS in MIMO-OFDM System

2013 ◽  
Vol 765-767 ◽  
pp. 2801-2804
Author(s):  
Ya Jing Wang ◽  
Ya Zhen Li ◽  
Li Qun Huang
Keyword(s):  
Spectral Efficiency ◽  
Communication System ◽  
High Speed ◽  
Fourth Generation ◽  
Ofdm System ◽  
Broadband Wireless ◽  
High Spectral Efficiency ◽  
Mimo Ofdm ◽  
Simulation Results ◽  
Improved Algorithm

The fourth generation mobile communication system is a high-speed broadband wireless communication system, it needs MIMO and OFDM technology which have high spectral efficiency and suitable for a multi-path fading channel. Because the MIMO-OFDM system is still an multi-carrier modulation system, the main drawback is the high PAPR value. This paper proposed an improved algorithm based on optimized PTS to reduce PAPR in STBC MIMO-OFDM system. The simulation results show that the improved algorithm can effectively reduce the PAPR value and do not increase the amount of computation in STBC MIMO-OFDM system.

A novel super-orthogonal modulation scheme for high speed optical OFDM system

2012 ◽  
Author(s):  
Qi Zhang ◽  
Xiangjun Xin ◽  
Lijia Zhang ◽  
Yongjun Wang ◽  
Chongxiu Yu ◽  
...  
Keyword(s):  
High Speed ◽  
Modulation Scheme ◽  
Ofdm System ◽  
Optical Ofdm ◽  
Orthogonal Modulation

An orthogonal multi-carrier source for realizing high speed all-optical OFDM system

2011 ◽  
Author(s):  
Jing Tang ◽  
Min Xia ◽  
Wei Li ◽  
Kecheng Yang ◽  
Xiaohui Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Ofdm System ◽  
All Optical ◽  
Optical Ofdm

scholarly journals BER PERFORMANCE ANALYSIS OF 4QAM/OFDM OVER DIFFERENT SCENARIOS OF LAPLACE FADING CHANNEL.

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-26-1-33
Author(s):  
Hassan F. Mohammed ◽  
◽  
Ghanim A. Al-Rubaye ◽  
Keyword(s):  
Fading Channels ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Additive White Gaussian Noise ◽  
Multipath Fading ◽  
Local Area ◽  
Ofdm System ◽  
Multicarrier Transmission ◽  
Simulation Results

Multicarrier transmission, also known as (OFDM) Orthogonal Frequency Division multiplexing, in wireless communications, it has been proven to be an essential technique for countering multipath fading. It has been used successfully for HF radio applications and has been selected as the interface for digital audio transmission, digital terrestrial TV broadcasting, and high-speed wireless local area networks in Europe. In this paper, we suggested a new design for modeling multipath fading channels, such as the Laplace fading channel, in order to discover new simulation results and effects. Furthermore, the variance of the Laplace fading channel has been computed and the new Bit Error Rate (BER) derivation is established, and the performance of (M-QAM), M-ary Quadrature Amplitude Modulation (with M=4 over OFDM system under Laplace fading channels in Additive White Gaussian Noise (AWGN) is discussed and compared to the conventional M-QAM/OFDM system Rayleigh fading channel in AWGN. All the simulation results are examined using the optimum signal detection based on the Euclidean distance and evaluated using Monte-Carlo simulation.

Research on Timing Synchronization Method for DC-Biased Optical OFDM Communication System

2013 ◽  
Vol 441 ◽  
pp. 911-914 ◽  
Author(s):  
Yong Wang ◽  
Yan Ling Jing
Keyword(s):  
Communication System ◽  
Direct Detection ◽  
Intensity Modulation ◽  
Timing Synchronization ◽  
Ofdm System ◽  
Synchronization Method ◽  
System Use ◽  
Optical Ofdm ◽  
Simulation Results

The timing synchronization methods for dc-biased optical OFDM system are different from wireless OFDM system because dc-biased optical OFDM system use intensity modulation/direct detection. Existing synchronization methods cant be used directly in dc-biased optical OFDM system. Therefore, the new timing synchronization method for dc-biased optical OFDM system is presented. The simulation results show that this timing synchronization method increasingly improves the estimated accuracy of dc-biased optical OFDM system.

Simulative Effect of Cyclic Prefix in Optical OFDM

2014 ◽  
Vol 661 ◽  
pp. 190-194
Author(s):  
A.O. Aldhaibani ◽  
S.A. Aljunid ◽  
Mohd Shamsul Anuar ◽  
A.R. Arief ◽  
H.Y. Ahmed
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Signal To Noise Ratio ◽  
Transmission Efficiency ◽  
Cyclic Prefix ◽  
Frequency Division ◽  
Interference Effects ◽  
Ofdm System ◽  
Guard Interval ◽  
Optical Ofdm ◽  
Simulation Results

Orthogonal frequency division multiplexing (OFDM) is one of the Multi-Carrier Modulation (MCM) techniques that transmit signals through multiple carriers. These carriers (subcarriers) have different frequencies and they are orthogonal to each other. There are different parameters which alter the performance of OFDM system. In this paper, the effect of cyclic prefix length (CP) on optical (OFDM) system is investigated. Although employing a CP as the guard interval is a simple way to combat inter-symbol interference (ISI) and inter-carrier interference (ICI), it reduces the transmission efficiency of the system. The simulation results show the effect of CP length in power receiver, penalty of power and improved the performance based on signal to noise ratio (SNR). In addition, a tradeoff is needed between reduced interference effects and transmission efficiency.

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