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Optical fiber communication



Professional Overview

Optical fiber is the abbreviation of optical fiber. Optical fiber communication is a communication method in which light waves are used as information carriers and optical fibers are used as transmission media. From a principle point of view, the basic material elements that make up optical fiber communication are optical fibers, light sources, and light detectors. In addition to the classification of optical fibers according to manufacturing process, material composition and optical characteristics, in applications, optical fibers are often classified according to use, and can be divided into optical fibers for communication and optical fibers for sensing. Transmission medium fiber is divided into general and special two types, and functional device fiber refers to the fiber used to complete the functions of light wave amplification, shaping, frequency division, frequency doubling, modulation and optical oscillation, and it is often used with a certain functional device. The form appears.

Optical fiber communication is a communication method that uses light waves as a carrier wave and optical fiber as a transmission medium to transmit information from one place to another. It is called "wired" optical communication. Nowadays, optical fiber is far superior to the transmission of cable and microwave communication due to its transmission frequency bandwidth, high anti-interference ability and low signal attenuation, and has become the main transmission method in the world communication.

In 1966, the British Chinese Charles Kao published a paper and proposed to use quartz to make glass filament (optical fiber), the loss can reach 20dB/km, which can realize large-capacity optical fiber communication. At that time, only a few people in the world believed, such as the British Standard Telecommunications Laboratory (STL), the American Corning Glass Company, Bell Labs and other leaders. In 2009, Gao Kun won the Nobel Prize for his invention of optical fiber. In 1970, Corning developed a quartz optical fiber with a loss as low as 20dB/km and a length of about 30 m, which was said to cost 30 million U.S. dollars. In 1976, Bell Labs established an experimental line in Atlanta, Washington, with a transmission rate of only 45Mb/s, which can only transmit hundreds of telephones, while the coaxial cable used can transmit 1800 telephones. Because there is no laser for communication at the time, light-emitting diodes (LED) are used as the light source for optical fiber communication, so the speed is very low. Around 1984, the semiconductor laser for communication was successfully developed. The speed of optical fiber communication reached 144Mb/s, which could transmit 1920 telephones. In 1992, the transmission rate of an optical fiber reached 2.5Gb/s, which is equivalent to more than 30,000 telephone lines. In 1996, lasers of various wavelengths were successfully developed, which can realize multi-wavelength and multi-channel optical fiber communication, which is the so-called "wavelength division multiplexing" (WDM) technology, which is to transmit multiple optical signals of different wavelengths in one optical fiber. . As a result, the transmission capacity of optical fiber communications is doubled. In 2000, using WDM technology, the transmission rate of an optical fiber reached 640Gb/s. Some people have big doubts about Gao Kun who invented optical fiber in 1976, but only won the Nobel Prize in 2010. In fact, it can be seen from the above optical fiber development history that despite the large capacity of optical fibers, the ultra-large capacity of optical fibers cannot be played without high-speed lasers and microelectronics. The speed of electronic devices has reached the order of gigabits/second. The emergence of high-speed lasers of various wavelengths has enabled optical fiber transmission to reach the order of terabits/second (1Tb/s=1000 Gb/s), and people have realized that "the invention of optical fiber" It has triggered a revolution in communication technology!"

Advantages and disadvantages

(1) Large communication capacity and long transmission distance; the potential bandwidth of an optical fiber can reach 20THz. With such a bandwidth, it only takes about one second to transmit all the textual data of human beings, ancient and modern, both at home and abroad. The 400Gbit/s system has been put into commercial use. The loss of the optical fiber is extremely low. The loss of the quartz fiber can be less than 0.2dB/km near the light wavelength of 1.55μm, which is lower than the loss of any transmission medium. Therefore, the non-relay transmission distance can reach dozens or even hundreds of kilometers.

(2) Small signal interference, good security performance;

(3) Anti-electromagnetic interference, good transmission quality, electrical communication cannot solve various electromagnetic interference problems, only optical fiber communication Not subject to all kinds of electromagnetic interference.

(4) The optical fiber is small in size, light in weight, easy to lay and transport;

(5) The source of materials is abundant, and the environmental protection is good, which is conducive to saving non-ferrous metal copper.

(6) There is no radiation and it is difficult to eavesdrop because the light waves transmitted by the optical fiber cannot escape outside the optical fiber.

(7) Optical cable has strong adaptability and long life.

(8) The texture is brittle and the mechanical strength is poor.

(9) The cutting and splicing of optical fiber requires certain tools, equipment and technology.

(10) Shunting and coupling are not flexible.

(11) The bending radius of the fiber optic cable should not be too small (>20cm)

(12) There is a problem of power supply difficulties.

A communication method that uses light waves to transmit information in optical fibers. Because laser has significant advantages such as high directivity, high coherence, high monochromaticity, etc., the light wave in optical fiber communication is mainly laser, so it is also called laser-fiber communication.

Principle and Application

The principle of optical fiber communication is: at the transmitting end, the transmitted information (such as voice) must first be converted into electrical signals, and then modulated to the laser beam emitted by the laser , The intensity of the light changes with the amplitude (frequency) of the electrical signal, and it is sent out through the optical fiber; at the receiving end, the detector converts the light signal into an electrical signal after receiving it, and restores the original information after demodulation.

As the transmission speed of information technology is updated day by day, optical fiber technology has been widely valued and applied. In the multi-computer elevator system, the application of optical fiber fully meets the requirements of a large number of correct, reliable, high-speed transmission and processing of data communication. The application of optical fiber technology in elevators greatly improves the response speed of the entire control system, and significantly improves the parallel group control performance of the elevator system. The optical fiber communication device used on the elevator is mainly composed of a light source, a photoelectric receiver and an optical fiber.

Light source

The signal output by the microcomputer control system is an electrical signal, while the optical fiber system transmits an optical signal. Therefore, in order to transmit the electrical signal generated by the microcomputer system in the optical fiber, first To convert electrical signals into optical signals. The light source is such an electro-optical conversion device.

The light source first converts the electrical signal into an optical signal, and then sends the optical signal to the optical fiber. In the fiber optic system, the light source has a very important position. Incandescent lamps, lasers and semiconductor light sources can be used as optical fiber light sources. Semiconductor light sources use semiconductor PN junctions to convert electrical energy into light energy. Commonly used semiconductor light sources include semiconductor light emitting diodes (LED) and laser diodes (LD).

Semiconductor light sources have been widely used in optical fiber transmission systems due to their small size, light weight, simple structure, convenient use, and easy compatibility with optical fibers.

Photoelectric receiver

The optical signal transmitted in the optical fiber must first be restored to the corresponding electrical signal before being received by the microcomputer system. This conversion is achieved through the optical receiver. The function of the optical receiver is to convert the optical signal transmitted by the optical fiber into an electric signal, and then the electric signal is handed over to the control system for processing. The optical receiver is based on the principle of photoelectric effect, irradiating the PN junction of the semiconductor with light, and the PN junction of the semiconductor will generate carriers after absorbing light energy, thus generating the photoelectric effect of the PN junction, thereby converting the optical signal into an electrical signal. Semiconductor receivers used in optical fiber systems mainly include semiconductor photodiodes, phototransistors, photomultipliers, and photovoltaic cells. The phototransistor can not only convert the incident light signal into an electrical signal, but also amplify the electrical signal, so that it can be well matched with the control system interface circuit, so the phototransistor is the most widely used.

Optical fiber

Optical fiber is the transmission channel of optical signal and the key material of optical fiber communication.

The optical fiber is composed of a core, a cladding, a coating and a jacket, and is a symmetrical cylinder with a multilayer dielectric structure. The main body of the core is silicon dioxide, which is doped with a small amount of other materials to increase the optical refractive index of the material. There is a cladding on the outside of the core, and the cladding and the core have different optical refractive indexes, and the optical refractive index of the core is higher to ensure that the optical signal is mainly transmitted in the core. There is a layer of coating on the outside of the cladding, which is mainly used to increase the mechanical strength of the optical fiber so that the optical fiber is not damaged from outside. The outermost layer of the optical fiber is a jacket, which also plays a protective role.

The two main characteristics of optical fiber are attenuation and dispersion. Loss is the attenuation or dispersion of an optical signal per unit length, expressed in db/km. This parameter is related to the transmission distance of the optical signal. The greater the loss, the shorter the transmission distance. Multi-microcomputer elevator control systems generally have short transmission distances, so in order to reduce costs, plastic optical fibers are mostly used. The dispersion of the fiber is mainly related to pulse broadening. In the Mitsubishi elevator control system, optical fiber communication is mainly used for data transmission between group control and single elevator and data transmission between two parallel single elevators. The optical fiber device used by Mitsubishi Elevator is mainly composed of a light source, a light receiver and an optical fiber. The light source and the light receiver are encapsulated in the fixed plug of the optical fiber connector, and the optical fiber is connected to the movable plug.

Wavelength Division Multiplexing Technology

WDM (Wavelength Division Multiplexing) technology refers to the use of multiple lasers to transmit multiple light waves of different wavelengths on the same optical fiber at the same time. It can greatly increase the transmission capacity of the optical fiber transmission system. The 1.6 Tbit/s WDM system has been commercialized on a large scale. In order to further increase the capacity of optical fiber transmission, DWDM (Dense Wavelength Division Multiplexing) has become a major international research object after 1995. Lucent Bell Labs believes that the capacity of commercial DWDM systems can reach up to 100 Tbit/s. DWDM based on 10 Gbit/s has gradually become the mainstream of core networks among many operators in my country. In addition to the continuous increase in the number of wavelengths and transmission capacity of the DWDM system, the optical transmission distance has also increased from 600 km to more than 2000 km. In addition, CWDM (Coarse Wavelength Division Multiplexing) has also emerged in the expansion of the metro optical transport network, with advantages such as ultra-large capacity, short-distance transmission and low cost. The researchers also found that wavelength division multiplexing of multiple optical time division multiplexed OTDM signals can greatly increase the transmission capacity. As long as it is properly combined, the transmission above Tbit/s can be realized. Therefore, it has become the development direction of optical fiber communication in the future. Most transmission experiments exceeding 3 Tbit/s in the laboratory are implemented in this way.

Optical soliton communication technology

Light is a special ultra-short optical pulse on the order of ps. After it is transmitted over a long distance through an optical fiber, its waveform and speed remain unchanged. Optical soliton communication is to use optical soliton as a carrier to realize long-distance and distortion-free communication, and the information transmission can reach thousands of miles under the condition of zero error. Numerous experiments have shown that it can be used for submarine optical cable communications, etc., and is suitable for combining with WDM systems to form ultra-high-speed and large-capacity optical communications. When the single-channel rate reaches more than 40 Gbit/s, the advantages of optical soliton communications can be fully reflected.

Optical fiber access technology

Optical fiber access uses PON technology to be combined with a variety of technologies, such as ATM\SDH and Ethernet, to produce APON, GPON, and EPON respectively. In contrast, EPON inherits the advantages of Ethernet and the cost is relatively low. After combining with fiber optic technology, EPON is not only limited to local area networks, but also extends to metropolitan area networks and even wide area networks. Fiber to the home also uses EPON technology; GPON has the most advantages in supporting circuit switching services and can make full use of the existing SDH technology, but the technology is more complex and the cost is high; APON will be used to implement the FTTH solution.

Working process

Send: CPU serializes parallel data through a dedicated IC chip, and inserts the corresponding bit code (start, stop, check digit, etc.) according to the communication format, The output terminal TXD sends the signal to the optical fiber connector (ie fixed plug), and then the light source in the optical fiber connector performs electrical-optical conversion. The converted optical signal sends the optical signal to the optical fiber through the optical fiber moving plug, and the optical signal is in the optical fiber. Propagating forward.

Receive: The optical signal from the optical fiber is sent to the receiver of the fixed plug through the movable plug of the optical fiber connector, and the receiver performs photo-electric restoration of the received optical signal to obtain the corresponding electrical signal , The electrical signal is sent to the RXD input terminal of the dedicated IC chip, and the serial data is changed to parallel data by the dedicated IC chip, and then transmitted to the CPU.

Application field

The application field of optical fiber communication is very wide. It is mainly used for local telephone trunk lines. The advantages of optical fiber communication can be fully utilized here, gradually replacing cables and being widely used. It is also used for long-distance trunk communication in the past, which mainly relied on cables, microwaves, and satellite communications. Now it is gradually using optical fiber communication and has formed a globally dominant bit transmission method; it is used in global communication networks and public telecommunication networks in various countries (such as China’s national first It is also used for high-quality color television transmission, industrial production site monitoring and dispatching, traffic monitoring and control command, urban cable television network, and common antenna (CATV) system. It is used in optical fiber local area network and other such as aircraft, spacecraft, ships, underground mines, electric power departments, military, corrosion and radiation, etc.

The optical fiber transmission system is mainly composed of: optical transmitter, optical receiver, optical cable transmission line, optical repeater and various passive optical devices. To achieve communication, the baseband signal must be processed by the electrical terminal and sent to the optical fiber transmission system to complete the communication process.

It is suitable for optical fiber analog communication system, but also suitable for optical fiber digital communication system and data communication system. In an optical fiber analog communication system, electrical signal processing refers to processing such as amplification and pre-modulation of baseband signals, while electrical signal reverse processing is the inverse process of originating processing, that is, processing such as demodulation and amplification. In optical fiber digital communication systems, electrical signal processing refers to the amplification, sampling, and quantization of baseband signals, namely pulse code modulation (PCM) and line code coding processing, etc., and electrical signal reverse processing is also the inverse process of origination. For data optical fiber communication, electrical signal processing mainly includes amplifying the signal, which is different from the digital communication system in that it does not require code conversion.

Professional settings

Basic information

Professional name: Optical fiber communication

Professional code: 590309

Training goals

This major trains application-oriented talents who can be engaged in the planning and construction of optical fiber network projects, the commissioning and maintenance of SDH systems, and the engineering and maintenance of telecom core networks and access networks. Possess strong cable and optical cable design and construction, line planning and budget estimation capabilities, and comprehensive professional capabilities in the installation, commissioning and maintenance of optical fiber communication equipment and related fields.

Main courses

Engineering drawing, circuit and signal, electronic technology, single chip microcomputer and embedded system, optical fiber communication principle, optical fiber communication equipment, integrated service access network, line engineering and budgetary estimate , CATV system, communication optical cable line, access network technology, communication power supply, computer application foundation, computer network foundation, digital communication principle, communication terminal equipment, etc.

Employment direction

Engaged in the design, construction, budget preparation and project supervision of optical fiber communication line projects and access networks; installation, commissioning, operation and maintenance of optical fiber communication equipment; communication network Planning and design, construction, supervision and other work.

Development

Optical fiber communication is the main transmission method of modern communication network. Its development history is only ten or twenty years, and it has experienced three generations: short-wavelength multi-mode fiber, long-wavelength multi-mode Optical fiber and long-wavelength single-mode optical fiber. The use of optical fiber communications is a major change in the history of communications. More than 20 countries including the United States, Japan, Britain, and France have announced that they will no longer build cable communications lines, and are committed to the development of optical fiber communications. China's optical fiber communication has entered the practical stage.

The birth and development of optical fiber communication is an important revolution in the history of telecommunications. Satellite communication and mobile communication are juxtaposed as technologies in the 1990s. After entering the 21st century, due to the rapid development of Internet services and the growth of audio, video, data, and multimedia applications, there is an even more urgent need for large-capacity (ultra-high-speed and ultra-long-distance) lightwave transmission systems and networks.

Optical fiber communication is the latest communication technology that uses light waves as carrier waves to transmit information, and optical fiber as the transmission medium to achieve information transmission and achieve the purpose of communication.

The development process of communication is the process of continuously increasing the carrier frequency to expand the communication capacity. As the carrier frequency, the optical frequency has reached the upper limit of the communication carrier. Because light is a very high-frequency electromagnetic wave, it uses light. As a carrier, the communication capacity is huge, which is thousands of times that of the past communication method, and has great appeal. Optical communication is a goal that people have long pursued, and it is also the inevitable direction of communication development.

Compared with the previous electrical communication, the main difference of optical fiber communication is that it has many advantages: its transmission frequency bandwidth, large communication capacity; low transmission loss, long relay distance; thin wire diameter, light weight, raw materials It is quartz, which saves metal materials and is conducive to the rational use of resources; it has strong insulation and anti-electromagnetic interference performance; it also has the advantages of strong corrosion resistance, strong radiation resistance, good windability, no sparks, small leakage, strong confidentiality, etc. , Can be used in special environment or military.

Trend

FTTH can provide users with extremely rich bandwidth, so it has always been regarded as an ideal access method. It plays an important role in realizing the information society, and requires large-scale promotion and Construction. The fiber required for FTTH may be 2 to 3 times that of the existing laid fiber. In the past, due to the high cost of FTTH, lack of broadband video services and broadband content, FTTH has not been on the agenda, and only a few trials. Due to the advancement of optoelectronic devices, the price of optical transceiver modules and optical fibers has been greatly reduced; coupled with the ease of broadband content, all have accelerated the practical process of FTTH.

The views of developed countries on FTTH are not exactly the same: AT&T in the United States believes that the FTTH market is small, and 0F62003 declared that FTTH will not have a market until 20-50 years later. US operators Verizon and Sprint are more active and will adopt FTTH to transform their networks within 10-12 years. Japan's NTT is the first to develop FTTH and has nearly 2 million users. China's FTTH is in the pilot phase.

Challenges encountered by FTTH

The widely used ADSL technology provides broadband services and still has certain advantages

Compared with FTTH: ①Low price ②Using the original The copper wire network makes the construction of the project simple ③It can meet the demand for the transmission of 1Mbps-500kbps film and television programs. Mass promotion of FTTH is restricted.

For broadband services to be developed in the near future, such as: online education, online office, conference TV, online games, remote diagnosis and treatment and other two-way services and HDTV high-definition digital television, uplink and downlink transmission asymmetric business, ADSL is difficult to satisfy. Especially HDTV, after compression, its transmission rate still needs 19.2Mbps. It is being developed with H.264 technology and can be compressed to 5 to 6 Mbps. It is generally believed that the highest transmission rate of ADSL that guarantees QOS is 2Mbps, and it is still difficult to transmit HDTV. It can be considered that HDTV is the main driving force of FTTH. That is, when HDTV services arrive, FTTH is a must.

FTTH solutions

Usually there are two categories: P2P point-to-point and PON passive optical network.

The advantages of the F2P scheme: each user transmits independently, does not affect each other, and the system changes flexibly; inexpensive low-speed optoelectronic modules can be used; and the transmission distance is long. Disadvantages: In order to reduce the number of optical fibers and pipes that users go directly to the office, an active node that summarizes users needs to be placed in the user area.

PON solution-advantages: passive network maintenance is simple; in principle, it can save optoelectronic devices and optical fibers. Disadvantages: need to use expensive high-speed optoelectronic modules; need to use electronic modules that distinguish users from different distances to avoid conflicts between users’ uplink signals; transmission distance is shortened by the PON ratio; the downlink bandwidth of each user occupies each other, if the user’s bandwidth is When there is no guarantee, not only is the network expansion required, but also the PON and the user module need to be replaced to solve the problem. (According to the market price, PEP is more economical than PON)

There are many kinds of PON, generally as follows: (1) APON: namely ATM-PON, suitable for ATM switching network. (2) BPON: Broadband PON. (3) OPON: OFP-PON using general frame processing. (4) EPON: PON using Ethernet technology, GPON is a Gigabit Ethernet PON. (5) WDM-PON: Use wavelength division multiplexing to distinguish users' PONs. Because users are related to wavelengths, it is inconvenient to maintain and is rarely used in FTTH.

The rapid development of wireless access technology. It can be used as the IEEE802.11g protocol for WLAN, with a transmission bandwidth of up to 54Mbps and a coverage range of more than 100 meters, which is already commercially available. If wireless access to WLAN is used for user data transmission, including: uplink and downlink data and VOD uplink data on demand TV, the uplink is not large for general users, and IEEE802.11g is sufficient. The FTTH using optical fiber is mainly to solve the downlink transmission of HDTV broadband video, of course, it can also include some downlink data when needed. This forms a "fiber to the home + wireless access" (FTTH + wireless access) home network. If this kind of home network adopts PON, it is particularly simple, because this PON does not have the upstream signal, does not need the electronic module of the distance measurement, the cost is greatly reduced, the maintenance is simple. If the user group belonging to the PON is covered by the wireless metropolitan area network WiMAX (1EEE802.16) and can be used, then there is no need to build a dedicated WLAN. The use of wireless access network is a trend, but the wireless access network still needs to be supported by an optical fiber network densely distributed near users, which is almost the same as FTTH. FTTH+ wireless access is the future development trend.

The development of optical switching

In fact, it can be expressed as: communication input + exchange.

Optical fiber only solves the transmission problem, but also needs to solve the optical switching problem. In the past, communication networks were composed of metal cables, which transmitted electronic signals, and used electronic switches for exchanges. The communication network, except for a short section at the end of the user, is all optical fiber, which transmits optical signals. A reasonable method should use optical switching. However, due to the immature optical switching devices, the only way to solve the optical network exchange is the "optical-electrical-optical" method, that is, the optical signal is converted into an electrical signal, and then the optical signal is changed back to the optical signal after the electronic exchange. Obviously an unreasonable method, it is not efficient and uneconomical. Large-capacity optical switches are being developed to realize optical switching networks, especially the so-called ASON-automatic switching optical networks. The information usually transmitted in the optical network is generally at a speed of xGbps, and electronic switches are not competent. Generally, electronic exchange should be realized in the lower order group. The optical switch can realize the exchange of high-speed XGbDs. Of course, it is not to say that everything needs to be exchanged with light, especially for low-speed, small-particle signal exchange, mature electronic exchange should be used, and there is no need to use immature

high-capacity optical exchange. At present, in the data network, signals appear in the form of "packets", using the so-called "packet switching". The particles of the bag are relatively small and can be exchanged electronically. However, after a large number of packets in the same direction are aggregated, when the number is large, a large-capacity optical switch should be used.

Optical switching with fewer channels and large capacity has been practical. For example, it is used for protection, drop off, and small-volume channel scheduling. Generally, mechanical optical switches and thermo-optical switches are used to achieve this. Due to the limitations of the volume, power consumption and integration of these optical switches, the number of channels is generally 8-16.

Electronic exchange generally has "space division" and "time division" methods. There are "space division", "time division" and "wavelength exchange" in optical switching. Optical time division switching is rarely used in optical fiber communications.

Optical space division switching: Generally, optical switches can be used to transfer optical signals from one fiber to another. Optical switches for air separation include mechanical, semiconductor and thermo-optical switches. Using integrated technology, the MEM micro-motor optical switch was developed, and its volume is as small as mm. The 1296x1296MEM optical switch (Lucent) has been developed, which is experimental.

Optical wavelength exchange: assign a specific wavelength to each exchange object. Thus, by sending a certain wavelength, it is possible to communicate with a certain object. The key to realizing optical wavelength switching is the need to develop practical variable-wavelength light sources, optical filters, and integrated low-power reliable optical switch arrays. A cross-connection test system (corning) combining 640x640 semiconductor optical switch + AWG space division and wavelength has been developed. Using optical space division and optical wavelength division can form a very flexible optical switching network. Japan's NTT conducted a field test using wavelength routing and switching in Chitose City, with a radius of 5 kilometers, a total of 43 terminal nodes, (trying 5 nodes), and a rate of 2.5Gbps.

The optical network of automatic switching, called ASON, is the direction of further development.

IntegrationOptoelectronic devicesDevelopment

Like electronic devices, optoelectronic devices should also move towards Integration. Although not all optoelectronic devices need to be integrated, a considerable part is needed and can be integrated. The PLC-planar optical waveguide circuit under development is like a printed circuit board on which optoelectronic devices can be assembled or directly integrated into an optoelectronic device. Whether to realize FTTH or ASON, new, small, inexpensive and integrated optoelectronic devices are needed.

The market for optical fiber communications

As we all know, the IT industry bubble in 2000 caused an explosive development of the optical fiber communications industry and overproduction of products. The prices of optical transmission equipment, optoelectronic devices and optical fibers have plummeted. Especially for optical fiber, the price per kilometer was ¥1200 during the bubble period, and the price was about Y100 for 1 kilometer, which was cheaper than copper wire. When will the optical fiber communications market recover?

According to RHK's statistics and forecasts on the North American communications industry investment, as shown in Figure 2. In 2002, it was the lowest point, which is equivalent to a four-year regression. There has been a rebound, but it cannot be recovered yet. Based on this speculation, it will be restored only in 2007-2008. The optical fiber communication market also improves with the IT market. These improvements have been driven to a large extent by FTTH and broadband digital TV.

FTTH is the demand of the information society after all, and the optical fiber communication market must have a beautiful scene. FTTH in developed countries has begun construction and there is already a considerable market. Generally speaking, the profits of devices and equipment will gradually pick up as the market needs, and 2007-2008 may be good. However, in the optical fiber industry, despite the success of anti-dumping, the price is still sluggish, and the profit is very small. In fact, in the world, the production scale of optical fiber is too large, and the development speed of FTTH is affected by the social environment, including the economic conditions of the citizens and the development of digital TV, and the rise is slow. It is understood that some large companies have sealed up several optical fiber factories and can start production at any time according to market conditions. As a result, supply always exceeds demand. It is a normal market law to increase prices when supply exceeds demand. Therefore, if the optical fiber industry wants to make substantial profits, it may be a matter after 2009. China's economically underdeveloped regions and small towns still need to build optical fiber lines, but the amount of optical fiber is still in the range of oversupply.

For the Chinese market, FTTH will be delayed due to the challenges of ADSL and the development of digital TV HDTV. The social environment and conditions for the massive construction of FTTH in China are not yet available, and it may take some time to wait. However, the Beijing Olympics requires the promotion of HDTV and the decline of equipment prices, which will promote the development of FTTH. It is expected that FTTH will start to be promoted in China in 2007-2008. However, there are also so-called central business district CBDs in some large cities, which have relatively strong economic power, and have already adopted fiber-to-residence PTTP for construction. In general, China's FTTH is in the pilot phase. The role of the pilot is to explore technology and construction experience on the one hand, and on the other hand, it also plays a role in competition to seize users. Therefore, telecommunications operators and local owners are actively piloting FTTH in order to develop broadband services. Therefore, broadcast operators are facing huge challenges. Broadcasters should speed up the process of developing digital TV, enrich the program content and adopt a competitive business model. If broadcasters want to develop VOD on-demand TV, they also need to transform the cable TV network in both directions. If the fiber optic network is adopted, it can more fully adapt to future technological development and market demand.

Broadband China Strategy

In the "Twelfth Five-Year Plan for Broadband Network Infrastructure" issued by the Ministry of Industry and Information Technology in May 2012, Realize "Urban fiber to the building into the home, rural broadband into the village into the village". The access bandwidth of urban households reaches 20 Mbit/s, and the access bandwidth of rural households reaches 4 Mbits/sec. The fiber-to-the-home coverage reaches 200 million households with more than 40 million users, and the fiber-to-the-home rate of newly built residential buildings in cities reaches more than 60%.

"The access mode and technology of my country's broadband market is mainly ADSL, while other countries with high broadband speed are basically fiber access." said Zhao Zisen, academician of the Chinese Academy of Engineering, realizing fiber to the home It is the most important part of the broadband strategy.

The academician of the Chinese Academy of Sciences Gan Fuxi said that optical fiber communication has the advantages of large information capacity, long transmission distance, and small signal interference. In the world's communication systems, more than 90% of the information is transmitted via optical fibers. In the next 5 to 10 years, my country's large-scale implementation of fiber to the home requires more than 100 million kilometers of fiber each year, which will bring good opportunities for the development of the domestic fiber optic communications industry.

According to the latest statistics of the International Telecommunication Union, 112 countries and economies have launched broadband strategies in the world. The implementation of the broadband strategy will surely bring about the great development of optical fiber access and make the optical fiber broadband industry one of the industries with the fastest growth and the largest development space in the entire information and communication industry.

Website

The global fiber-to-the-home hotspot portal-China Fiber Optic Communication Network, is a leading domestic fiber optic communication information portal website. With the rapid development of China's triple play and fiber-to-the-home, there are fewer online platforms for users to communicate, and professional information is more scattered. The opening of China's optical fiber communication portal provides a large-scale professional platform for enterprises, users, and enthusiasts in the industry to exchange industry information and exchange product information on the Internet.

The advantage of China's optical fiber communication portal is to provide industry information, news, professional knowledge, countless product supply and demand information, as well as an open operation model, diversified value-added services, and user-friendly layout design. Allows you to better and more advanced grasp of the dynamics in the industry, to obtain more business opportunities. Thus, it provides a rare opportunity and opportunity for the majority of optical fiber communication enterprises to expand their network business and enter e-commerce.

The characteristics of China's optical fiber communication portal:

Information exchange, technical communication, product display, information reading, news subscription, supply and demand, seeking business opportunities, advertising services, membership promotion, enterprise establishment, Personality construction, association information, exhibition resources, industry talents, business agents, etc.

Policies

Industry policies, development space

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