Through nearly a week's study, we have learned a lot from sensibility, which has a far-reaching impact on our future study and research direction. Through this internship, I enriched my theoretical knowledge, enhanced my observation ability, broadened my horizons, and gave me a qualitative understanding of my future work, which really made me gain a lot. Now I will summarize this internship from three aspects: the content of the internship, the harvest of the internship, the direction of my own efforts in the future, and my feelings.
Preparatory work:
September 1, attended the cognitive practice mobilization meeting. At the meeting, the teacher who led the team explained to us in detail the matters needing attention during the internship and the unified arrangement of the internship these days, and encouraged everyone to ask questions to the technicians frequently during the internship. I hope I can have a better and deeper understanding of this major through this internship.
First, visit the internship content
1. Communication System Laboratory of China Geo University
On September 2nd, under the guidance of our teacher, we went to China Geo University by bus and visited the communication system laboratory there. There, we learned that the Communication System Laboratory of China Geo University is an important experimental teaching base for undergraduates and postgraduates majoring in communication and information technology, and it is an open laboratory integrating experimental teaching and scientific research. It provides a good training environment for cultivating innovative talents and a platform for school-enterprise cooperation and exchange. The overall goal of the system is to establish an experimental platform.
While following the teacher's tour, the internal teacher introduced that the communication experimental system consists of Huawei's metro series optical transmission products, c & ampC08 program-controlled switches, ma5300 broadband equipment, h3c layer 2 and layer 3 data communication equipment, wireless access and other five hardware platforms and special communication software. With the support of special software (e-bridge, t2000, etc.). ), each platform can provide both independent experiments and systematic experiments, and provide a variety of end-to-end communication solutions, which can accommodate 35 students to operate on the computer at the same time.
Relying on this platform, we can complete the teaching experiment, course design, production practice, graduation design and scientific research of communication and information specialty. The platform can cover courses such as access network technology, program-controlled switching, optical fiber communication, sdh, computer communication network, information management and security, telecommunication signaling and communication protocol, multimedia communication, voice processing, image processing, communication principle, mobile communication, electromagnetic field and electromagnetic wave. At the same time, the platform can support Huawei optical transmission network and h3c network training and certification services, and those who pass the certification examination can issue corresponding certification certificates.
For the future development of the secondary laboratory, the teacher emphasized that innovation comes from practice. Under the guidance of Premier Wen's "seeking truth from facts", the laboratory has been built into a first-class, fully functional and innovative communication experimental teaching base in China.
2. Chang Fei Optical Cable Co., Ltd.
On September 3rd, early in the morning, we drove to Chang Fei Optical Fiber and Cable Co., Ltd. for an internship. In the lobby, the relevant staff of the company introduced us to the general situation of the company.
Chang Fei Company was established in May of 1988, which was jointly invested by China Telecom Group, Dutch Drake Communication Technology Company and Wuhan Changjiang Communication Group Co., Ltd. It is the only professional manufacturer in China with integrated scale production capacity of rod making, wire drawing and cable forming. The company is located at No.4, Guanshan Second Road, Donghu High-tech Development Zone, Wuhan, covering an area of 1 50,000 square meters, with a total of10,000 employees and annual sales of nearly 3 billion yuan. It is the R&D and production base of optical fiber and cable products with the most complete product specifications, the most advanced production technology and the largest production scale in China.
Since 1992 was put into production, the production and sales volume of optical fiber and cable products of Chang Fei Company ranked first in China for 16 years, with a cumulative production and sales of 52.5 million core kilometers of optical fiber and 0.23 million sheath kilometers of optical fiber/kloc-0 (36 million kilometers of optical fiber), with total sales exceeding 20 billion yuan. Products are exported to more than 50 countries and regions such as the United States, Japan, Southeast Asia, the Middle East and Africa, making it the second largest optical fiber manufacturer and the fifth largest optical fiber manufacturer in the world.
Since its establishment, Chang Fei Company has explored a successful way to revitalize the national industry through introduction, digestion, absorption and innovation.
R&D Center is a department of Chang Fei Company, which specializes in manufacturing technology, production technology, manufacturing equipment and materials. There are doctors, postdoctoral fellows 13, 54 masters, undergraduates 103 and 22 senior technical experts, who are committed to the development and research of new optical fiber and cable products with world-leading level.
Up to now, Chang Fei Company has obtained national authorized patents 109, including 5 invention patents1. At the same time, it also obtained a number of American patent authorizations.
At the same time, Chang Fei Company has undertaken many national key projects, such as the Tenth Five-Year Plan, the information industry technology upgrading project of the National Development and Reform Commission, the national "863" project, the "Science and Technology Boosting Trade" project, the national torch plan project, the key science and technology project of Hubei Province, and the "R&D of export mechanical and electrical products" project of the Ministry of Commerce. And won the National Science and Technology Progress Award 1 item, Hubei Province 1 item and Wuhan City 2 items.
In addition, Chang Fei has also made great efforts to develop independent innovation infrastructure. It has been successively recognized as the postdoctoral industrial base in Hubei Province, the provincial enterprise technology research and development center in Hubei Province, the optical communication material engineering research center in Hubei Province, the national "863" plan achievement industrialization base, the annual innovative enterprise in China information industry, the national enterprise technology center and the Wuhan optical fiber communication engineering technology research center.
Since 1992 was put into production, Chang Fei Company has produced and sold 52.5 million core kilometers of optical fiber, and optical fiber1230,000 picokilometers (36 million kilometers of optical fiber), with total sales exceeding 20 billion yuan. The production and sales volume of optical fiber products and optical cable products ranked first in China, second and fifth in the world respectively for 16 years.
In the domestic market, Chang Fei's optical fiber products and optical cable products are widely used in China Telecom, China Netcom, China Mobile, China Unicom, China Tietong and other communication operators, as well as power, radio and television, transportation, education, national defense, aerospace, chemical industry, petroleum, medical care and other industries, with a national market share of over 40%.
In the international market, Chang Fei Company has exported about100000 core kilometers of optical fiber and cable products. Products are exported to more than 50 countries and regions such as the United States, Japan, Southeast Asia, the Middle East and Africa, and the international market share exceeds 10%.
While introducing modern production technology, Chang Fei Company also introduced modern management science and system, especially modern quality management procedures, so that every production link of Chang Fei Company is under strict and scientific quality control.
1993, through the comprehensive audit of Kyle Company in the Netherlands, Chang Fei Company became the first enterprise in the national optical fiber and cable industry to obtain iso9002 international quality system certification.
In 200 1 year, Chang Fei Company started the enterprise resource planning system with erp system, and implemented the whole process quality monitoring from raw material procurement, contract review, product production, finished product delivery to after-sales service to ensure that products, processes and services meet the needs of users.
In 2002, Chang Fei Company obtained iso900 1:2000: 2000 international standard certification, which indicates that the quality management system of Chang Fei Company has developed from the original introduction and reference mode to the self-improvement and continuous improvement mode.
By 2007, the drawing length of its single-strand optical fiber preform exceeded 2,000 kilometers, and it won the titles of "Top 500 Manufacturing Enterprises in China" and "The Most Influential Enterprise of China Optical Fiber and Cable in Thirty Years".
Follow the staff to visit the production process of optical fiber and cable related products, and have a good understanding of the production of the whole preform.
Since the establishment of 1999, Fiberhome Communication has taken the industrialization of multimode optical fiber as an important task and implemented a leap-forward development strategy. First of all, in the original pilot plant, by improving equipment performance, adding new pcvd equipment and improving process technology, the ratio of optical fiber production and sales in 200 1 year to 1999 increased by five times. Meanwhile, in Wuhan? The newly-built optical fiber factory in China Guanggu will be put into production soon. In addition to the mass production of single-mode optical fiber, the latest generation of pcvd equipment will be used to produce high-performance multimode optical fiber, and the production capacity will be increased by 4-5 times on the existing basis. Dmd measurement is an indispensable technology in the research of new generation 50/ 125 multimode optical fiber. Fiberhome communication is fully prepared. R&D personnel collected and studied relevant technical data, purchased dmd measuring equipment, and studied the process of eliminating rip defects.
3. Fiberhome Communication Technology Co., Ltd..
company profile
Fiberhome Communication Technology Co., Ltd. (Fiberhome Communication) is an excellent provider of equipment and network solutions in China's information and communication field, the only industrialization base of "863" plan achievements in the field of optical communication recognized by the Ministry of Science and Technology, and "Wuhan? One of the leading enterprises in China Optics Valley.
The company was founded on 1999, and Fiberhome Communications A shares were listed on the Shanghai Stock Exchange on 200 1. Wuhan Institute of Posts and Telecommunications, the main sponsor of Fiberhome Communication, is the research center of optical fiber communication engineering in China and the birthplace of optical communication in China. China's first optical fiber, the first optical communication project and a series of major scientific and technological achievements were all developed here.
Fiberhome Communication has mastered a large number of core technologies in the field of optical communication, ranking first in the domestic industry in terms of scientific research foundation and strength, conversion rate and benefit of scientific research achievements, and participating in the formulation of more than 200 national standards and industry standards. In recent years, Fiberhome Communications has undertaken the R&D and industrialization of the National 863 Plan "40gb/ssdh Optical Fiber Communication Equipment and System", "Automatic Switched Optical Network" and "tbpsdwdm Transmission System Development", which represents the country's impact on the world's leading technologies.
Fiberhome communication is the mainstream supplier of national basic network construction, and its product categories cover three series: optical network, broadband data and optical cable.
The share of optical transmission equipment and optical cables ranks first in China, with 65,438+10,000 sets of online stable operation equipment, and the national basic optical cable trunk network is equipped with optical cables 1 10,000-kilometer long; Ulhwdm, 3.2tdwdm and ason systems, which represent the highest level in the industry, were first applied to the national first-class trunk network of telecom operators; Ftth takes the lead in commercial development ... Innovative network equipment, perfect customer service and personalized solutions constantly create long-term value for customers. Fiberhome Communication adheres to the industrial road of sustainable development, and has also made good achievements in the fields of information network security, billing software and comprehensive services.
Based on the enterprise spirit of "innovation, service, responsibility and common development", Fiberhome Communication will further enhance its capital operation ability, asset operation ability, product development ability, market expansion ability, quality service ability and strong administrative management ability around the development of its main business, the cultivation of its core competence and the exertion of its overall advantages, so as to make Fiberhome Communication brand bigger, better and stronger.
Fiberhome Communication has a first-class production base in Asia with a total area of about 80,000 square meters, including a modern communication system equipment production workshop and an optical fiber and cable manufacturing workshop. More than 50 kinds of technical equipment and production lines with contemporary international advanced level have been introduced, with an annual production capacity of 5 billion yuan.
R&D strength
Fiberhome Communication has long focused on the research and development of the overall solution of communication network from the core layer to the access layer. Over the years, it has undertaken most of the "863" and "tackling key problems" projects in the field of optical fiber communication during the Eighth Five-Year Plan, the Ninth Five-Year Plan and the Tenth Five-Year Plan, and has been moving towards practicality.
Fiberhome Communications invests a lot of scientific research funds every year and implements the people-oriented talent strategy. It has a huge R&D group, including academicians of China Academy of Engineering, members of itu-t expert group and young and middle-aged experts with outstanding contributions at the national level. It keeps up with customers' needs in time and provides competitive and unique solutions for users' core interests.
In 2005, the key project "40gb/ssdh optical fiber communication equipment system" passed the acceptance; The 3.2t(80×40g)dwdm system, which represents the largest capacity in China, was first applied in the first-class trunk line project of China Telecom. "Fiberhome" entered the national first-class trunk market and was commercialized on a large scale; Ftth system was first commercialized in China and exported overseas.
In 2004, ason system with completely independent intellectual property rights was successfully applied to Shanghai Telecom.
In 2003, the national 863 project "Research and implementation of wdm ultra-long distance optical transmission technology" passed the acceptance; China's first ultra-long distance system with independent intellectual property rights is applied to the construction of national first-class trunk lines;
In 2002, 1.6tdwdm system took the lead in large-scale application in the first-class trunk line project of China Telecom. The msr technology (x.87) proposed by the representative of Fiberhome Communication of China International Telecommunication Union was accepted by itu-t and determined as the technical specification of metropolitan optical transport network.
200 1, oxc and oad systems have been successfully applied to China high-speed information demonstration network;
In 2000, Fiberhome Communications proposed the first ITU ip standard (x.85/x.86), which was adopted by itu-t; Opening the first 32×2.5gdwdm (Guiyang-Xingyi) national trunk line project in China;
1997 the first domestic 2.5gsdh (Haikou-sanya) national trunk line project was opened;
1990, take the lead in opening a number of pdh national first-class trunk lines, such as Beijing-Hanguang;
The technological breakthrough with independent intellectual property rights has brought a broad market space for Fiberhome Communication and strongly promoted the development of national optical communication industry.
Second, the internship harvest
1. Preform
According to interviews and related references on the Internet, the 30-year development of multimode fiber can be roughly divided into three stages.
The first stage, 197 1 ~ 1980, is the research and development period of multimode fiber. During this period, the traditional double crucible process was gradually eliminated in the world, and four new chemical vapor deposition preform processes, such as mcvd, ovd, vad and pcvd, were developed. From multi-component oxide glass fiber to time-sensitive glass fiber: The transmission theory and fiber design of multimode fiber are studied, and the key technologies to optimize preform process and improve bandwidth of multimode fiber by analyzing the measurement results of differential mode delay (dmd) are emphatically developed. The multimode optical fiber communication system is tested in the field. Establish the industry standard of 50/ 125mm gradient multimode fiber (hereinafter referred to as 50 -mmf). 50 mm -mmf put into mass production. Representative ones are Corning's Wilmington Optical Fiber Factory 1979, which was put into operation in June, and T Company's at & Atlanta Optical Fiber Factory 1979 was expanded in April and put into operation the following year. 1980 The global annual output of optical fiber is less than 65438+ million kilometers, and 100% is multimode fiber. This is the beginning of the optical fiber industry. In the following 20 years, the annual output of mmf increased rapidly, reaching 4 million km in 2000 (see table 1).
The second stage, 198 1 ~ 1995, is the development period of practical multimode fiber and the addition of new varieties. Worldwide, a practical trunk optical fiber communication system has been established using 50 -mmf. However, in the first few years of this period (1983 ~ 1984), the technology of single-mode fiber (g.652a fiber) was mature, and the position of 50 -mmf in the inter-office trunk fiber communication system was quickly replaced by single-mode fiber. Since then, 50 -mmf has turned to the field of data transmission, mainly used in local area network (lan). At that time, in order to reduce the cost of LAN system as much as possible, low-priced light-emitting diodes (LEDs) were widely used instead of expensive semiconductor lasers (ld) as light sources. The divergence angle of led is much larger than that of ld, but the core diameter and numerical aperture of 50φ-MMF are relatively small at that time, which is not conducive to efficient coupling with led. In order to make the connection and coupling easier and make the optical power coupled into the fiber more powerful, gradient multimode fibers with larger core diameter and larger numerical aperture have been developed internationally, such as 62.5/ 125, 80/ 125, 100/ 140. Shortly thereafter, most of the market share of 50 -mmf was replaced by the emerging 62.5/ 125-mm gradient multimode fiber. However, multimode optical fibers such as 80/ 125, 100/ 140 have not been widely used for many reasons, such as large bending loss, high manufacturing cost and special cladding diameter. During this period, multimode fiber gradually replaced the traditional copper wire and coaxial cable, and became the preferred physical medium for modern ultra-high-speed LAN systems.
In the third stage, 1996-2002, the research and development of multimode fiber entered the latest active period. It is estimated that the active period will last until 20 10. During this period, the local area network system developed to the ultra-high speed above GB/S, and Ieee adopted the Gigabit Ethernet standard in June 1998. In June 2002, the 10gb/s Ethernet standard was just passed. This ultra-high-speed LAN system must use laser as light source and a new generation of high-performance multimode fiber. In addition to 10gb/s Ethernet standard, there are many industrial standards that will adopt the new generation of multimode fiber.
Corning, Lucent ofs and draka in the Netherlands have all introduced this new generation of multimode fiber samples. The promulgation of various industrial standards provides a unified foundation for the development, production and application of this kind of optical fiber, and more optical fiber manufacturers will invest in the development and production of a new generation of multimode optical fiber. It is predicted that after 2002, it will be the golden age for multimode fiber to achieve greater development.
At present, there are four processes for preparing optical fiber preforms, namely, external vapor deposition (ovd), axial vapor deposition (vad), improved vapor deposition (mcvd) and plasma chemical vapor deposition (pcvd). The optical characteristics of optical fiber core rod mainly depend on the manufacturing technology of core rod, while the cost of optical fiber preform depends on cladding technology. At present, the manufacturing technologies of optical fiber cladding include sleeve method, plasmaspary method invented by alcatel, soot method invented by Lucent Technology Company of the United States and sol-gel method, among which soot method refers to flame hydrolysis external deposition processes such as ovd and vad.
However, mcvd method now uses external deposition technology instead of casing method to make large-scale preforms, forming a mixed process combining external deposition technology of mcvd, thus changing the shortcomings of traditional mcvd process, such as slow deposition speed and poor geometric dimension accuracy, reducing production costs and improving the quality of preforms. Since then, some companies have developed low-cost and large-size casing technology, and the casing preparation technology is sol-gel method and ovd method.
In recent twenty years, the preparation process of preform ovd has developed from single torch deposition to multi-torch simultaneous deposition, and the deposition rate has doubled. One equipment can deposit multiple rods at the same time, from one-step method of sequentially depositing core cladding to two-step method, that is, the large-diameter mandrel is prepared first, then the small-diameter mandrel is drawn or not, and then the optical fiber preform is prepared by cladding technology, which improves the production efficiency and reduces the production cost. Moreover, mcvd method, especially pcvd method, ovd method and vad method, is easier to accurately control the radial refractive index distribution of mandrels, so it is more effective for preparing multimode fiber mmf and non-zero dispersion fiber dzdf core preforms.
In recent 20 years, the cladding technology of optical fiber preform has made great progress. At the beginning of 1980, optical fiber preform was prepared by sleeve method, which changed the manufacturing process of optical fiber preform from one-step method to two-step method. For the first time, Corning Company of the United States adopted soot outsourcing technology instead of casing method for industrial production. 1990, Alcatel plasma spraying technology and sol-gel outsourcing technology developed by Lucent Company of the United States replaced the sleeve technology, so the manufacturers who used the sleeve method to prepare optical fiber prefabricated vad and manufacture optical fiber mandrels all adopted the soot outsourcing technology.
2. Dense wavelength division multiplexing optical transmission system
The latest news released by China Communication Research Institute, Fiberhome Communication "80*40gb/s Dense Wavelength Division Multiplexing Optical Transmission System" won the first prize of China Communication Science and Technology Research Institute in 2007.
Fiberhome Communication adopts nrz code for 40gb/sdwdm transmission for the first time in China. Raman fiber amplifier technology has been successfully applied to 80*40gb/sdwdm system for the first time in China, which is innovative in accurate dispersion management of 40gb/sdwdm system, distributed Raman amplification and optical signal-to-noise ratio analysis software of unequal span distributed Raman amplification. The first ultra-high-speed and ultra-large-capacity DWDM optical transmission system which can be extended to 80 * 40Gb/s at home and abroad was successfully built in Shanghai and Hangzhou, and the actual service was loaded, and the whole line was running stably, filling the domestic gap. The successful development and engineering application of 80*40gb/sdwdm system is an important milestone in the development of high-speed optical fiber communication in China, which indicates that China has gradually approached or even surpassed the international advanced level in the research and development and productization of ultra-high speed, ultra-large capacity and ultra-long transmission distance optical communication systems. From catching up to surpassing, this is a solid step for China to become a powerful country in communication R&D, manufacturing and operation.
3. Optical fiber communication
Transparent optical fiber is used to transmit light waves. Efficiency and speed are far superior to wired communication. Synchronous digital hierarchy (sdh) is a digital communication system in optical fiber communication system. This is a new set of international standards. Sdh is not only a networking principle, but also a set of multiplexing methods. In order to overcome the shortcomings of pdh, Sdh came into being. It has a clear goal, then standardizes, and then develops equipment. In this way, the systems and equipment needed for the future communication network can be set up in the most perfect way. Sdh was officially recommended by ccitt in 1988, also called synchronous digital hierarchy. Sdh is a very important standard, which is not only suitable for optical fiber communication, but also suitable for microwave and satellite communication in principle.
Third, the direction of my own efforts in the future and my feelings this time.
After two years of study in school, we have mastered some basic theories and technologies of communication specialty, so it is very necessary to go out of school and practice in the information industry.
Through this practice, I learned the basic knowledge of communication specialty, broadened my horizons, increased my knowledge, learned some simple principles of communication equipment, and learned the latest development of the current industry. I applied the knowledge in books to practice, and at the same time I gained a lot of valuable knowledge wealth. On the other hand, I also see my own shortcomings. Still have to study hard, learn more relevant knowledge, enrich experience, consult teachers and related personnel, and pass various courses.
Through internship, we have the opportunity to face professionals, listen to their professional explanations and personally see many large-scale communication equipment, which is very helpful for us to understand knowledge and connect with reality, and is very beneficial to our future work. Through practice, we can understand the position and function of communication in the development of national economy, deepen our perceptual knowledge of communication engineering in production and life, understand the production and operation rules of these enterprises, learn the organizational management knowledge of these enterprises, consolidate the theories we have learned, cultivate our preliminary practical work ability and professional and technical ability, and enhance our academic background and love for the electronic information specialty.
Through various forms, I understand the development status and bright future of the communication industry. Feel the wonderful life brought by information technology today. Of course, I will devote myself to the communication industry in the future, focusing on the research of new mobile communication technologies. Therefore, when you choose to continue your graduate studies next year, you should strive to engage in the research of mobile communication and let yourself grow up as soon as possible.