[Objective]This paper discusses full lifecycle energy efficiency of optical communication systems in the purpose of en-ergy conservation and carbon reduction.It aims to establish a universal model for description of energy efficiency,which covers all stages of system lifecycle,and it is not limited to specific technologies or network structures.It also analyzes the key influ-encing factors for improvement of energy efficiency of optical communication systems.[Methods]This paper explores the use-ful work and energy consumption of optical communication systems,to establish a universal model for energy efficiency.In the expression of useful work,in addition to the commonly used factor data rate,distance factor is introduced as an important fac-tor.The paper recommends that the value generated by data transmissions which meet specific quality requirements and main-taining network connectivity in specific scenario applications should be considered in the description of the useful efficacy.The description method is named as comprehensive useful efficacy.In the discussion of energy consumption,the system lifecycle is decomposed into four stages:manufacturing,installation and construction,operation and maintenance,and waste recycling.Main influencing factors of energy efficiency improvement are discussed based on the established model.[Results]Main results of the research include:(1)Distance factor can be one of the main factors for evaluating the useful work of a system,and dis-tance factors affect energy consumption at various stages of the system's lifecycle;(2)For new scenarios and applications,set-ting weights for data transmissions which meet specific quality requirements and assigning values for maintaining connectivities status in description of the system useful work could reflect the value brought by the energy cost of the system to meet the needs of scenario applications;(3)Energy consumption factors of each stage of the life cycle should be considered in evaluation of energy consumption of the full lifecycle,and the energy consumption of each stage should be converted into unit time based on the system operating life for accumulation;(4)Optimized network topology and routing design,reduction of line losses,as well as evolution of optical transmission technology and equipment/facility energy saving technologies,are important means to reduce energy consumptions throughout the entire lifecycle of the system and improve the energy efficiency.[Conclusion]This paper discusses the comprehensive useful work and full life cycle energy consumption of optical communication systems,and establishes a universal model to describe the full life cycle energy efficiency of the system.This model takes distance as an im-portant influencing factor in the expression of the useful efficiency and also energy consumption of the system,which corre-sponds the value of the optical communication system based on communication distance with the energy consumption in the life-cycle caused by distances.It also suggests considering the value generated by data transmissions which meet specific quality requirements and maintaining network connectivity in the evaluation of the useful efficiency.This model could comprehensively evaluate the energy efficiency of optical communication systems,for improvements of system energy efficiency,and could adapt and promote applications of optical communication systems in new scenarios.

[Objective]This paper studies numerical characteristics and characteristic matrix of attenuation spectrum of G.652.D single-mode optical fibres,and considers the attenuation factor to optimize the mathematical expression of optical fibre attenua-tion spectrum model.The study aims to improve the digital modeling ability of optical fibre attenuation spectrum for research and manufacturing of optical fibre and development of optical system.[Methods]ITU-T G.650.1(2020)provides an example matrix for use in the"spectral attenuation modelling"method to calculate attenuation spectrum of G.652.D single-mode optical fibres.This paper analyzes and demonstrates that the spectral attenuation model method could approximately obtain optical fi-bre attenuation spectrum with low error by characteristic matrix corresponds to four wavelengths.An optimized attenuation spectrum characteristic matrix is given by considering sources of attenuation,and the effect of the new matrix is verified with attenuation spectrum test data of 1000 fibre samples.[Results]Main research results of this paper include:(1)When there is a good correspondence between the wavelengths corresponding to the fibre attenuation spectrum characteristic matrix and main attenuation sources of G.652.D fibre,the spectral attenuation model method is able to approximate the fibre attenuation spec-trum with small errors;(2)An attenuation spectrum characteristic matrix of G.652.D single mode fibre is calculated based on attenuation sources of the fibre,and this matrix is able to reflect mechanism of fibre attenuation better,compared to the char-acteristic matrix calculated solely from data;(3)Verification with test data of optical fibre samples shows that the new matrix could calculate the attenuation spectrum of optical fibre samples with comparable small errors.[Conclusion]This paper studies and concludes that the reason why the spectral attenuation model method is able to approximate the optical fibre attenuation spectrum is that the corresponding wavelengths of the characteristic matrix has a good correspondence with main attenuation sources of the optical fibre.Combining with the attenuation sources,optimized characteristic matrix can be calculated.The new matrix could reflect the mechanism of the optical fibre attenuation and also effectively calculate the attenuation spectrum of the optical fibre samples with small errors.

当前光接入网的连接对象和覆盖场景不断拓展,光接入网的拓扑结构需要满足网络发展的新需求.本文研究探讨了光接入网的拓扑结构描述方式,提出了从光纤层面和光缆层面两个角度对光接入网的拓扑结构描述.在光纤层面,对现行国际标准规定的光接入网拓扑结构进行了调整;在光缆层面,对光接入网的主要拓扑单元进行了梳理归纳.两者相结合,可衔接光接入网承载的光系统和物理设施部署,更有效地对光接入网拓扑结构进行描述.

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