scholarly journals K-means Cluster Algorithm Applied for Geometric Shaping Based on Iterative Polar Modulation in Inter-Data Centers Optical Interconnection

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2417
Author(s):  
Xia Sheng ◽  
Qi Zhang ◽  
Ran Gao ◽  
Dong Guo ◽  
Zexuan Jing ◽  
...  

The demand of delivering various services is driving inter-data centers optical interconnection towards 400 G/800 G, which calls for increasing capacity and spectrum efficiency. The aim of this study is to effectively increase capacity while also improving nonlinear noise anti-interference. Hence, this paper presents a state-of-the-art scheme that applies the K-means cluster algorithm in geometric shaping based on iterative polar modulation (IPM). A coherent optical communication simulation system was established to demonstrate the performance of our proposal. The investigation reveals that the gap between IPM and Shannon limit has significantly narrowed in terms of mutual information. Moreover, when compared with IPM and QAM using the blind phase searching under the same order at HD-FEC threshold, the IPM-16 using the K-means algorithm achieves 0.9 dB and 1.7 dB gain; the IPM-64 achieves 0.3 dB and 1.1 dB gain, and the IPM-256 achieves 0.4 dB and 0.8 dB gain. The robustness of nonlinear noise and high capacity enable this state-of-the-art scheme to be used as an optional modulation format not only for inter-data centers optical interconnection but also for any high speed, long distance optical fiber communication system.

The improvement in technology over long distance communication using optical fiber has been regulated over past few decades, and it took drastic enhancement in one of the major parameter for joining two OFC cable (splicing). The different experiments performed in order to bring about the result that can give nearly 0dB splice loss when there is shifting of entire set up of Optical Fiber Communication. The splicing loss is created by the joining of two SMF using fiber optic fusion splicing. The objective of this paper is to determine the low splice loss in joining two single mode or multimode optical fiber, such that long distance communication that required multiple infrastructure assembly for its operational unit can be made relocatable as there is large investment and material and electronic circuitry is associated to it. Therefore to reduce that cost we have sets of analysis that splicing loss can be reduced to 0dB for SMFSMF end face connection or at least no improvement in splice losses while relocation of OFC infrastructure from one place to other place as the result of the tested experiment. Based on experiment conducted we came to conclusion that with essential requirements for establishing a low-loss and high-speed communication line using optical fibers, the need for quality of splicing technology along with perfect core alignment angle is required to reduce splice loss, such that the infrastructure can be shifted to many different location without any additional cost of new material and new resources. The exact measurement of splice loss can be insured by another set of formula which we came across during the experimental performance.


Author(s):  
Mehak Bilal

Abstract: This study shows an easy and effective design of an optical fiber communication system, which demonstrates EDFA's ideal position in the whole system. In recent years, erbium-doped fiber amplifiers (EDFAs) have been more attentive with the development of high-speed and long-distance data transmission systems. In our research, EDFA's forward pump capacity is maintained at 100mW, and our three configurations modify and analyze the location of EDFA. First configuration is meant to place EDFA before optical fiber in the entire system. The second arrangement has been intended such that EDFA will precede optical fiber. EDFA is inserted in the third configuration between the optical fiber length. For the three setups, the BER, Q factor and output power level were observed, with the setup one having minimal BER, setup two with the greatest power, and setup three with the maximum Q factor. This paper discusses the causes behind these results and designers may construct an optical fiber communication system in the most efficient and reliable fashion by taking those results into consideration. The simulation was performed in Opti-System software. Keywords: EDFA, BER, Q factor, Analyzer, Optical fibre


Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Baile Chen ◽  
Yaojiang Chen ◽  
Zhuo Deng

High speed photodetectors operating at a telecommunication band (from 1260 to 1625 nm) have been well studied with the development of an optical fiber communication system. Recent innovations of photonic systems have raised new requirements on the bandwidth of photodetectors with cutoff wavelengths from extended short wavelength infrared (eSWIR) to long wavelength infrared (LWIR). However, the frequency response performance of photodetectors in these longer wavelength bands is less studied, and the performances of the current high-speed photodetectors in these bands are still not comparable with those in the telecommunication band. In this paper, technical routes to achieve high response speed performance of photodetectors in the extended short wavelength infrared/mid wavelength infrared/long wavelength infrared (eSWIR/MWIR/LWIR) band are discussed, and the state-of-the-art performances are reviewed.


2014 ◽  
Vol 926-930 ◽  
pp. 2034-2037
Author(s):  
Yan Kuan Liang

In order to realize the large capacity of ultra-high-speed optical fiber transmission, optical modulation and reuse is one of crucial technology. This article discusses MAMSK modulation format all-optical OOFDM transmission system. The MAMSK modulation format with the method of phase modulation combined with multiple amplitude modulation, at the same time on the signal phase and amplitude modulation information, achieve the goal of lower code rate. All-optical OOFDM multiplexing technology is the electric field of OFDM, half its adjacent subcarrier frequency spectrum overlap, so the spectrum efficiency is very high, is a kind of very potential recovery technology.


2017 ◽  
Vol 38 (2) ◽  
Author(s):  
Li Li ◽  
He Feng

AbstractDispersion and nonlinear effects will increase the effect on the system when the optical information transmits in high speed and long distance. The new optical modulation technology can reduce the attenuation caused by transmission procedure. In this paper, OptiSystem and Matlab were combined to set a model by comparing the dispersion tolerance and nonlinear effect of different code modulation formats. After that, the better performance code of IRZ (Inverse Return-to-Zero) and DQPSK (Differential Quadrature Phase Shifted Keying) will be used to study their properties in 10Gbit/s re-modulation WDM-PON access model. The DQPSK was used in downlink, IRZ modulation was used in uplink adopts the IRZ modulation was used in 10 Gbit/s re-modulation WDM passive optical network access model uplink on the basis of the above method. A simulation analysis is also made between the different duty ratios of the DQPSK and IRZ. Compared with the NRZ type, the IRZ has a better anti-dispersion property, channel crosstalk suppression ability and higher spectrum efficiency although it costs 3 dB powers. At the same time, it simplifies the structure of the ONU on the premise of not increasing the power and the cost. So, it fits the large capacity requirements between user stations and the central office in the future.


1905 ◽  
Vol 59 (1537supp) ◽  
pp. 24627-24628
Author(s):  
Charles A. Mudge

2021 ◽  
Vol 11 (9) ◽  
pp. 4232
Author(s):  
Krishan Harkhoe ◽  
Guy Verschaffelt ◽  
Guy Van der Sande

Delay-based reservoir computing (RC), a neuromorphic computing technique, has gathered lots of interest, as it promises compact and high-speed RC implementations. To further boost the computing speeds, we introduce and study an RC setup based on spin-VCSELs, thereby exploiting the high polarization modulation speed inherent to these lasers. Based on numerical simulations, we benchmarked this setup against state-of-the-art delay-based RC systems and its parameter space was analyzed for optimal performance. The high modulation speed enabled us to have more virtual nodes in a shorter time interval. However, we found that at these short time scales, the delay time and feedback rate heavily influence the nonlinear dynamics. Therefore, and contrary to other laser-based RC systems, the delay time has to be optimized in order to obtain good RC performances. We achieved state-of-the-art performances on a benchmark timeseries prediction task. This spin-VCSEL-based RC system shows a ten-fold improvement in processing speed, which can further be enhanced in a straightforward way by increasing the birefringence of the VCSEL chip.


Author(s):  
V. Gall ◽  
E. Rütten ◽  
H. P. Karbstein

AbstractHigh-pressure homogenization is the state of the art to produce high-quality emulsions with droplet sizes in the submicron range. In simultaneous homogenization and mixing (SHM), an additional mixing stream is inserted into a modified homogenization nozzle in order to create synergies between the unit operation homogenization and mixing. In this work, the influence of the mixing stream on cavitation patterns after a cylindrical orifice is investigated. Shadow-graphic images of the cavitation patterns were taken using a high-speed camera and an optically accessible mixing chamber. Results show that adding the mixing stream can contribute to coalescence of cavitation bubbles. Choked cavitation was observed at higher cavitation numbers σ with increasing mixing stream. The influence of the mixing stream became more significant at a higher orifice to outlet ratio, where a hydraulic flip was also observed at higher σ. The decrease of cavitation intensity with increasing back-pressure was found to be identical with conventional high-pressure homogenization. In the future, the results can be taken into account in the SHM process design to improve the efficiency of droplet break-up by preventing cavitation or at least hydraulic flip.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1997
Author(s):  
Bin Lu ◽  
Haijun Xuan ◽  
Xiaojian Ma ◽  
Fangjun Han ◽  
Weirong Hong ◽  
...  

Labyrinth-honeycomb seals are a state-of-the-art sealing technology commonly used in aero-engine interstage seal. The undesirable severe rub between the seal fins and the honeycomb due to the clearance change may induce the cracking of the seal fins. A pervious study investigated the wear of the seal fins at different radial incursion rates. However, due to the axial thrust and mounting clearance, the axial rub between the seal fins and the honeycomb may occur. Hence, this paper focuses on the influence of the axial rub added in the radial rub on the wear of the seal fins. The rub tests results, including rubbing forces and temperature, wear rate, worn morphology, cross-sectional morphology and energy dispersive spectroscopy results, are presented and discussed. Overall, the participation of the axial rub leads to higher rubbing forces, temperature, and wear rate. The tribo-layer on the seal fin is thicker and the cracks are more obvious at high axial incursion rate. These phenomena indicate the axial rub has a negative influence on the wear of the seal fins and should be avoided.


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