scholarly journals On the Theoretical Performance Limits of Long Repeated/Regenerated Optical IMDD Links

2021 ◽  
Author(s):  
Fredy Francis ◽  
Manivasakan R
Keyword(s):  
Optical Networks ◽  
Signal To Noise Ratio ◽  
Input Power ◽  
Physical Parameters ◽  
Noise Power ◽  
Performance Limits ◽  
Computational Overhead ◽  
Lower Transmission ◽  
And Performance ◽  
Performance Gains

Abstract The introduction of optical amplifiers has drastically increased the capacity and the reach of optical transmission links. However, they add Amplified Spontaneous Emission (ASE) noise, which progressively degrades the Signal to Noise Ratio (SNR) when cascaded and ultimately limits the transmission reach and performance. This is conventionally offset using regenerators, typically Optical-Electrical-Optical (OEO) conversion devices, that recreate the signal restoring its source SNR, albeit with bit errors due to the hitherto accumulated noise. These OEO regenerators tend to be expensive and add to the link latency, which sets the scene for widespread commercial implementation of all-optical regenerators in the near future. Our work aims to analyze the ideal, best-case theoretical gains achievable using an all-regenerator optical link as compared to an all-repeater link. So, this analytical study serves as a benchmark against which future link performance gains can be compared. We also translate this bound on BER advantage to extra reach or lower transmission power. We compare and contrast the evolution of noise power and BER down the link using the derived analytical expressions. The theoretical comparative study is then evaluated by incorporating the physical parameters of the devices. Both results agree and prove the dramatic increase in link reach achievable using all-regenerator links with minor input power penalties. Further, certain approximations to reduce the computational overhead for the described methods are proposed, which should find applications in dynamic reconfigurable optical networks.

To Mitigate the Effect of Cross-Phase Modulation by Employing PC-DCF Technique in Multi-Tone RoF System

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Namita Kathpal ◽  
Amit Kumar Garg
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Phase Modulation ◽  
Performance Metrics ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Input Power ◽  
System Capacity ◽  
Bit Rate ◽  
Cross Phase Modulation

AbstractIt is known that the high bandwidth demands are accomplished by deploying the concept of wavelength division multiplexing in optical networks which involves the transmission of multiple wavelength signals spaced very close to each other. Due to closely spaced wavelengths, the signal power of one channel phase modulates the adjacent channel which in turn produces nonlinear effects such as cross-phase modulation (XPM), self-phase modulation (SPM) and four-wave mixing (FWM). Thus, in this paper, PC-DCF (pre-compensating dispersion compensating fiber) technique has been demonstrated and evaluated in the transmission link to compensate the XPM effects, and this result seems to significantly enhance w.r.t. transmission performance and system capacity considering performance metrics such as Optical Signal to Noise Ratio (OSNR), bit rate, Q-factor and bit error rate (BER). It is evident from the simulation results as well as through mathematical modeling that the proposed technique (PC-DCF) provides optimum results at the channel spacing of 100 GHz, bit rate of 10 Gbps and input power of 5 mW which collectively provides a 5 dB increase in OSNR as compared to the existing compensating technique.

scholarly journals Performance Optimization of Diagonal Identity Matrix and Enhanced Double Weight Codes in Terms of Security for Short Haul Communication

2020 ◽  
Vol 8 (5) ◽  
pp. 2301-2304
Keyword(s):  
Optical Networks ◽  
Performance Optimization ◽  
Signal To Noise Ratio ◽  
Extinction Ratio ◽  
Input Power ◽  
Extensive Literature ◽  
Identity Matrix ◽  
Data Traffic ◽  
Optimal Parameters ◽  
Multiple User

Optical code division multiplexing is getting attention because it is an imminent multiple access technology which can cater ever increasing data traffic as well as multiple user access in optical networks. In this work, a zero cross correlation based diagonal identity matrix code is presented and it is compared with the enhanced double weight code to check the superior code in OCDMA system at data speed of 30 Gbps. Effect of some parameters of OCDMA system which prominently affects the security of the system and these are input power, linewidth and modulator extinction ratio. Optimization using single parameter optimization and multiple parameter optimizations has been done. In order to accomplish the work, optiwave optisystem software is used and extensive literature survey is done, issues encountered are carefully checked and to address the issues, proposed system is presented. Results are evaluated in terms of Q factor, bit error rate (BER) and signal to noise ratio. Novelty of proposed work is the search of optimal parameters of both the codes in terms of enhanced security such that eavesdropping at these optimal parameters will become tedious for unauthorized user.

Detection Sensitivity Based on Energy Detection in Cognitive Radio Systems

2012 ◽  
Vol 462 ◽  
pp. 500-505
Author(s):  
Gui Cai Yu ◽  
Cheng Zhi Long ◽  
Man Tian Xiang
Keyword(s):  
Signal To Noise Ratio ◽  
Energy Detection ◽  
Detection Algorithm ◽  
Detection Sensitivity ◽  
Dynamic Threshold ◽  
Noise Power ◽  
Power Fluctuation ◽  
New Energy ◽  
And Performance ◽  
Short Time

Traditional energy detection algorithm is bad in anti-noise. In this paper, the relationship of energy detection performance and detection sensitivity with average noise power fluctuation in short time is investigated. Detection sensitivity drops quickly with the increment of average noise power fluctuation and becomes worse in low signal-to-noise ratio. To the characteristic, a new energy detection algorithm based on dynamic threshold is presented. Theoretic results and simulations show that the proposed scheme removes the falling proportion of performance and detection sensitivity caused by the average noise power fluctuation with a choice threshold, and also improves the antagonism of the average noise power fluctuation in short time and obtains a good performance. Detection sensitivity and performance improves as the dynamic threshold factor increasing.

Comparative Simulation of Thermal Noise Effects for Photodetectors on Performance of Long-Haul DWDM Optical Networks

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed
Keyword(s):  
Optical Networks ◽  
Wavelength Division Multiplexing ◽  
Thermal Noise ◽  
Signal To Noise Ratio ◽  
Avalanche Photodiode ◽  
Input Power ◽  
Superior Performance ◽  
Noise Effects ◽  
Wavelength Division ◽  
The Impact

AbstractLong-haul 16-channel dense-wavelength division multiplexing networks employing two different avalanche photodiode (APD) structures (Si and InGaAs) and positive-intrinsic-negative (PIN) photodetectors are simulated and compared under thermal noise effects for different fiber lengths. The effect of thermal noise level on the transmission quality with a variation of amplifying section length, number of amplifying sections and channel speed is discussed. The impact of thermal noise on the system performance is analyzed by varying input power from −5dBm to 20dBm for both 25 km and 50 km amplifying section at 100 km fiber length. The performance is evaluated for both 5 Gb/s and 10 Gb/s data rates over transmission distances up to 500 km. A comprehensive comparison is developed based on signal-to-noise ratio (SNR), quality factor (Q-factor) and bit error rate (BER). It is found that both APD structures achieve superior performance up to distance of 350 km comparing to PIN photodetectors for 50 km amplifying section. The system provides optimum performance at input power Pin = 10dBm in case of 50 km amplifying section, but then afterwards, the performance is degraded rapidly due to nonlinearities. The results revealed that the worst performance scenario is at 10–18 W/Hz thermal noise in terms of higher BER and lower Q-factor. Finally, the desirable BER of 10–12 is achieved at Q-factor of 6.78 and SNR of 23 dB.

scholarly journals Crosstalk Analysis and Performance Evaluation for Torus-Based Optical Networks-on-Chip Using WDM

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 985
Author(s):  
Tingting Song ◽  
Yiyuan Xie ◽  
Yichen Ye ◽  
Shujian Wang ◽  
Yingxue Du
Keyword(s):  
Numerical Simulations ◽  
Optical Networks ◽  
Insertion Loss ◽  
Network Performance ◽  
Noise Power ◽  
Worst Case ◽  
Optical Router ◽  
Networks On Chip ◽  
And Performance ◽  
On Chip

Insertion loss and crosstalk noise will influence network performance severely, especially in optical networks-on-chip (ONoCs) when wavelength division multiplexing (WDM) technology is employed. In this paper, an insertion loss and crosstalk analysis model for WDM-based torus ONoCs is proposed to evaluate the network performance. To demonstrate the feasibility of the proposed methods, numerical simulations of the WDM-based torus ONoCs with optimized crossbar and crux optical routers are presented, and the worst-case link and network scalability are also revealed. The numerical simulation results demonstrate that the scale of the WDM-based torus ONoCs with the crux optical router can reach 6 × 5 or 5 × 6 before the noise power exceeds the signal power, and the network scale is 5 × 4 in the worst case when the optimized crossbar router is employed. Additionally, the simulated results of OptiSystem reveal that WDM-based torus ONoCs have better signal transmission quality when using the crux optical router, which is consistent with previous numerical simulations. Furthermore, compared with the single-wavelength network, WDM-based ONoCs have a great performance improvement in end-to-end (ETE) delay and throughput according to the simulated results of OPNET. The proposed network analysis method provides a reliable theoretical basis and technical support for the design and performance optimization of ONoCs.

Enhancements of Non-contact Measurements of Electrical Waveforms on the Proximity of a Signal Surface Using Groups of Pulses

2002 ◽  
Author(s):  
Fenglei Du ◽  
Greg Bridges ◽  
D.J. Thomson ◽  
Rama R. Goruganthu ◽  
Shawn McBride ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Signal To Noise Ratio ◽  
Electrostatic Force ◽  
Single Pulse ◽  
Electric Signal ◽  
Measurement Instruments ◽  
Cycle Times ◽  
Force Microscopy ◽  
And Performance

Abstract With the ever-increasing density and performance of integrated circuits, non-invasive, accurate, and high spatial and temporal resolution electric signal measurement instruments hold the key to performing successful diagnostics and failure analysis. Sampled electrostatic force microscopy (EFM) has the potential for such applications. It provides a noninvasive approach to measuring high frequency internal integrated circuit signals. Previous EFMs operate using a repetitive single-pulse sampling approach and are inherently subject to the signal-to-noise ratio (SNR) problems when test pattern duty cycle times become large. In this paper we present an innovative technique that uses groups of pulses to improve the SNR of sampled EFM systems. The approach can easily provide more than an order-ofmagnitude improvement to the SNR. The details of the approach are presented.

Information Theoretic Analysis and Performance Gains of 3-Color Shift Keying

2021 ◽  
pp. 1-1
Author(s):  
Alexandros E. Tzikas ◽  
Panagiotis D. Diamantoulakis ◽  
George K. Karagiannidis
Keyword(s):  
Theoretic Analysis ◽  
Information Theoretic ◽  
Color Shift ◽  
Shift Keying ◽  
And Performance ◽  
Performance Gains

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

Sign in / Sign up

Export Citation Format

Share Document