Journals >Study On Optical Communications
Contents
2023
Volume: 49 Issue 5
11 Article(s)
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Research Articles
Research on Real-time Free-Space Optical Transmission Experiment Demonstration based on Delta-Sigma Modulation
Zhong-zhong WANG, Xue-yuan AO, and Qi YANG
To simplify the structure of real-time coherent Free-Space Optical (FSO) / wireless systems and reduce costs, this paper implements a low-cost FSO system based on bandpass Delta-Sigma Modulation (DSM) technology. A 256-ary Quadrature Amplitude Modulation (256-QAM) signal with a bandwidth of 400 MHz and a rate of 1.6 GbTo simplify the structure of real-time coherent Free-Space Optical (FSO) / wireless systems and reduce costs, this paper implements a low-cost FSO system based on bandpass Delta-Sigma Modulation (DSM) technology. A 256-ary Quadrature Amplitude Modulation (256-QAM) signal with a bandwidth of 400 MHz and a rate of 1.6 Gbit/s is generated to realize a 10 Gbit/s Polarization Division Multiplexed-Quadrature Phase Shift Keying (PDM-QPSK) signal after DSM. The real-time transmission in a 50 m FSO link with a sensitivity of -46.2 dBm is achieved. The experimental results indicate that the combination of coherent detection and DSM is a promising technology for future optical wireless scenarios..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 1 (2023)
SSBI Elimination Technology in Single Side Band Direct Detection System
Wei WANG, Fan LI, and Zhao-hui LI
Single Side Band (SSB) direct detection system is considered as an attractive solution for 80 km Data Center Interconnects (DCI), due to its characteristics of low-cost, simple system architecture, and high robustness to chromatic dispersion. However, Signal to Signal Beating Interference (SSBI) is the major problem inSingle Side Band (SSB) direct detection system is considered as an attractive solution for 80 km Data Center Interconnects (DCI), due to its characteristics of low-cost, simple system architecture, and high robustness to chromatic dispersion. However, Signal to Signal Beating Interference (SSBI) is the major problem in SSB direct detection system. In order to address the SSBI in the SSB direct detection systems, the SSB modulation realized by IQ modulator and Dual Drive Mach Zehnder Modulator (DDMZM) is investigated. A SSB signal reconstruction algorithm based on time domain iteration and an SSBI-free direct detection scheme based on DDMZM are proposed respectively for these two SSB direct detection systems. The implementation principle and simulation or experimental setup are introduced in detail. According to the simulation and experimental results, the effectiveness and feasibility of the two schemes in SSBI elimination are discussed..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 5 (2023)
Joint PAPR Reduction Technology Enabled by Neural Network-based Coding and Companding
Jun-yuan Nie, Da-wei Zhang, and Jing Zhang
Multi-carrier modulation technology is an advanced modulation method commonly used in broadband communication systems. However, multi-carrier signals will produce a very large Peak to Average Power Ratio (PAPR) in the time domain, which will lead to non-linear damage and seriously affects the performance of system. In Multi-carrier modulation technology is an advanced modulation method commonly used in broadband communication systems. However, multi-carrier signals will produce a very large Peak to Average Power Ratio (PAPR) in the time domain, which will lead to non-linear damage and seriously affects the performance of system. In this paper, a joint PAPR reduction technology enabled by neural network-based coding and companding is proposed. The frequency-domain coding is implemented by a fully connected layer, which greatly reduces the complexity and difficulty of network training. A small proportion of spread spectrum is introduced to provide coding gain, and the time-domain companding network uses a nonlinear convolutional neural network to reduce PAPR. The effect of the scheme is shown through simulation under various parameter conditions, and compared with various schemes. The simulation results show that the scheme can reduce PAPR by 5 dB while introducing rare distortion. Finally, the scheme is experimentally verified. The experimental results show that the Bit Error Ratio (BER) is reduced by 75% compared with the clipping scheme when the PAPR is reduced by 5 dB, which verifies the feasibility of the scheme..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 16 (2023)
Performance Analysis of MIMO-FSO System based on Quadrature Amplitude Modulation
Pu LI, Xuan TANG, Jing XU, and Yang CHEN
Free Space Optical (FSO) communication systems are easily affected by atmospheric turbulence effects. In order to reduce the Bit Error Rate (BER) of the system under saturated turbulence condition, and considering the requirement of maximum diversity gain under limited Signal Noise Ratio (SNR) in practical engineering,Free Space Optical (FSO) communication systems are easily affected by atmospheric turbulence effects. In order to reduce the Bit Error Rate (BER) of the system under saturated turbulence condition, and considering the requirement of maximum diversity gain under limited Signal Noise Ratio (SNR) in practical engineering, it is necessary to study the diversity performance of the system to obtain the relationship between diversity gain and parameters such as SNR and system link number. This article uses Multiple-Input-Multiple-Output (MIMO) technology to design a MIMO-FSO system based on Quadrature Amplitude Modulation (QAM). The performance of the system in a negative exponential distribution channel model is analyzed, and the BER calculation formula and closed form expressions of diversity gain related parameters (such as Diversity Order (DO), Incremental Diversity Order (IDO), and speed of convergence (SOC)) are derived. Simulation experiments are conducted using mathematical software such as Matlab to verify the accuracy of the derived formula through Monte Carlo simulation. The simulation results show that MIMO the technology can significantly reduce the BER of FSO systems without increasing the transmission power and receiving aperture area. Moreover, in saturated turbulent channels, when the number of system links increases or the turbulence intensity decreases, the diversity order increases to the theoretical maximum with the SNR at a faster rate. The MIMO technology effectively suppresses the negative impact of atmospheric turbulence on the system and significantly improves system performance. When conditions are satisfied, using more transmitters and receivers can achieve higher diversity gain in the system under limited SNR. However, it is also necessary to consider the deployment cost and installation difficulty in actual engineering to choose the appropriate number of links..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 23 (2023)
Evaluation of Service Bearing Performance of SDON Optical Transmission Network in Electric Power Communication
Li-xia ZHANG, Jian-liang ZHANG, Yi AN, Xiao-rui HU, and Jun-hong NI
At present, the performance demand of power communication service for bearer network is constantly increasing. Software Defined Optical Network (SDON) technology drives the integration of power communication and SDON technology with its advantages of openness and softwareization. The index system and evaluation method At present, the performance demand of power communication service for bearer network is constantly increasing. Software Defined Optical Network (SDON) technology drives the integration of power communication and SDON technology with its advantages of openness and softwareization. The index system and evaluation method established based on traditional optical transmission network cannot reflect the characteristics of SDON architecture and its influence on bearer performance of power communication network service. In this paper, a new index system is constructed based on the performance requirements, influencing factors and the influence of different SDON architectures on the service performance of power communication business. The decision matrix was determined according to the contribution degree of the index to each attribute. The Ordered Weighted Average-Extended-Technique for Order of Preference by Similarity to Ideal Solution (OWA-E-TOPSIS) multi-attribute decision making method was proposed to realize the index screening. The weight distribution of the selected indicators is carried out by Analytic Hierarchy Process (AHP), and the examples are collected. After the pretreatment by utility function method, the index value aggregation is carried out. By comparing the evaluation results of each instance, the feasibility of the index system and evaluation method are verified, which provided a basis for the application of new technology and new business support of electric power communication network..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 30 (2023)
Research on Basic Management and Control System of Computing Force Network based on SRv6
Xu HUANG, Meng-hong CHENG, and Zhi-yan CHENG
With the new concept of computing force network being put forward, how to manage, cooperate and deploy after the integration of computing power and network has become an urgent problem for telecom operators. To better solve the problems of unified management, perceptual dispatch, and collaborative arrangement of multi-With the new concept of computing force network being put forward, how to manage, cooperate and deploy after the integration of computing power and network has become an urgent problem for telecom operators. To better solve the problems of unified management, perceptual dispatch, and collaborative arrangement of multi-dimensional resources such as network, computing, and storage, we study from the direction of computing force network management and control. Then we investigate the overall architecture design of computing force network management and control system, the core capabilities, and the evolution of underlying network technology. Based on the principle of "the network changes with the computing force, and the network strengthens the computing force", the collaborative mode of "horizontal connection and vertical dispatch" of the computing force network is formed with the help of the management and control system capabilities. Eventually, we believe it will effectively support the development demands of computing force network business and help the development of the national "Eastern Data and Western Computing" project..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 38 (2023)
Research on Networking Strategy of the New Generation Government Enterprise Dedicated Line Transmission Network
Guo-xin ZHANG, Xian-hu WEI, and Fan WANG
Aiming at the problems of the existing Optical Transport Network (OTN) dedicated line bearer network, such as poor delay performance, low service opening efficiency, and low network intelligence, the paper proposes the networking strategy of the new generation government enterprise dedicated line bearer network. It givAiming at the problems of the existing Optical Transport Network (OTN) dedicated line bearer network, such as poor delay performance, low service opening efficiency, and low network intelligence, the paper proposes the networking strategy of the new generation government enterprise dedicated line bearer network. It gives the application suggestions of 100/200 Gbit/s, packet enhanced OTN, OTN cluster, Reconfigurable Optical Add-Drop Multiplexer (ROADM)/Optical Cross-Connect (OXC) and other new transmission technologies. The relevant results are also applied to the commercial deployment of an operator's government enterprise dedicated line bearer network. The results show that the construction of the new generation government enterprise special line bearer network has significant economic and social benefits. The delay of the operator's network in the key financial direction has reached the leading level in the industry. The opening time of the private line service has been shortened from the previous average of 60 days to 15 days. At the same time, the operator has the ability to automatically open the end-to-end service..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 45 (2023)
Study on Optical Fiber Oxygen Sensing of Fluorinated Dry Gel Sensitive Materials
Zheng-lan BIAN, Su-hang YANG, Feng-hong CHU, Chun-peng ZHAO... and Shi FENG|Show fewer author(s)
In order to accurately measure the Dissolved Oxygen (DO) concentration, and enhance the sensitivity and stability of sensor head, two fluorinated dry gel oxygen sensitive materials 3, 3, 3-Trifluoropropyltrimethoxy/Tetraethyl Orthosilicate (TFP-TriMOS/TEOS) and 3, 3, 3-Trifluoropropyltrimethoxy/1, 2-Bis (triethoxysilylIn order to accurately measure the Dissolved Oxygen (DO) concentration, and enhance the sensitivity and stability of sensor head, two fluorinated dry gel oxygen sensitive materials 3, 3, 3-Trifluoropropyltrimethoxy/Tetraethyl Orthosilicate (TFP-TriMOS/TEOS) and 3, 3, 3-Trifluoropropyltrimethoxy/1, 2-Bis (triethoxysilyl) Ethane (TFP-TriMOS/BTESE) fluorinated hybrid dry gel dope with Ruthenium (Ru) complex were developed by improved sol-gel technology. Oxygen sensing head was made by dip coating plastic optical fiber into the above prepared sol-gel. Its oxygen sensing performance was studied under different precursor ratios. Experimental results show that all the fabricated DO sensing heads have good oxygen sensing performance, and the detection limits are 0.135 and 0.118 mg/L, respectively. Compared with the fiber optic oxygen sensing head coated with a single precursor (TEOS, BTESE and TFP-TriMOS), the fiber optic oxygen sensing head based on fluorinated dry gel shows higher linearity and lower detection lower limit. The stability of the fluorinated DO sensing head and the influence of pH the intensity of fluorescence signal was studied. The results show that the two kinds of fiber optic dissolved oxygen sensing head have good stability and anti-interference ability..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 50 (2023)
Research on Green and Environmentally Friendly Manufacturing Process of Optical Fiber Preform
Dong-ming CUI, Chang-jun PAN, Ming KONG, Kang XIE, and Zhi-jian LIU
In view of the defects of high energy consumption and pollution in the traditional optical fiber preform manufacturing process, this paper proposes a green and environmentally friendly cladding manufacturing process with quartz sand as raw material. Through the selection and analysis of quartz sand raw materials, it isIn view of the defects of high energy consumption and pollution in the traditional optical fiber preform manufacturing process, this paper proposes a green and environmentally friendly cladding manufacturing process with quartz sand as raw material. Through the selection and analysis of quartz sand raw materials, it is shown that natural quartz sand is suitable for the manufacture of optical fiber preforms. Through the research on the key control points of the natural quartz sand preform making process, the quartz sand is filled into the prefabricated assembly consisting of a core rod and a thin-walled quartz tube. A large-size G.652.D optical fiber preform with an average outer diameter of 155 mm is then successfully prepared by high-temperature melting and shrinking. After fiber drawing and testing, the optical parameters can meet the low water peak optical fiber standard. There is no exhaust gas emission in the process raw material of quartz sand can be completely converted, which is more low-carbon and environmentally friendly than traditional optical fiber preform manufacturing process..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 56 (2023)
Research on the Cable Sag On-line Monitoring Using Spontaneous Brillouin Scattering
Xiao-juan LI, Jian-ke LI, Li-jun LIU, Yong-qian LI, and Li-xin ZHANG
To improve transmission line load capacity and prevent power grid accidents, an online sag monitoring system for overhead transmission lines based on spontaneous Brillouin scattering is designed using the principles of Brillouin scattering and coherent detection. Brillouin Optical Time Domain Reflection (BOTDR) technolTo improve transmission line load capacity and prevent power grid accidents, an online sag monitoring system for overhead transmission lines based on spontaneous Brillouin scattering is designed using the principles of Brillouin scattering and coherent detection. Brillouin Optical Time Domain Reflection (BOTDR) technology is used to collect the strain signal distributed along the optical fiber in real time, extract the key features of strain sensing, and realize the accurate positioning and early warning of sag anomaly points. Laboratory data and substation test results show that the system can detect and accurately locate strain change information in real time. The strain monitoring system is simple in single-end measurement and can accurately locate the strain mutation point. It can realize the early warning of cable sag abnormalities, and can timely detect and deal with potential faults to ensure the safe and stable operation of the transmission line..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 63 (2023)
Study and Design of Mid-infrared Apodized Grating-based Filters
Feng-long LIANG, Shao-nan ZHENG, Yang QIU, Qi-ze ZHONG... and Ting HU|Show fewer author(s)
Aiming at the problem of the application of the integrated photonic filter in the 3～5 μm atmospheric window banda mid-infrared add-drop filter based on the apodized grating-assisted contra-directional coupler (contra-DC) is studied and designed. The complementary lateral-misalignment method is used for phase modulationAiming at the problem of the application of the integrated photonic filter in the 3～5 μm atmospheric window banda mid-infrared add-drop filter based on the apodized grating-assisted contra-directional coupler (contra-DC) is studied and designed. The complementary lateral-misalignment method is used for phase modulation to achieve spectral sidelobe suppression and eliminate spectral distortion and broadening caused by the conventional lateral-misalignment modulation method. Simulation results show that the device can achieve a high Sidelobe Suppression Ratio (SLSR) of 22 dB, bandpass filter spectrum is flat at the top and the filtering spectrum is close to the box shape. The device has low insertion loss of about 0.4 dB through port and 0.45 dB drop port..
Study On Optical Communications
- Publication Date: Oct. 10, 2023
- Vol. 49, Issue 5, 67 (2023)
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