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1 Characteristics of the development of optical fiber technology
1.1 The development of the network puts new demands on optical fiber
The Next Generation Network (NGN) has sparked many ideas and debates. Some experts predict that no matter how the next generation network develops, it will reach three worlds, namely the IP world at the service level, the world of light at the transport level, and the wireless world at the access level. The next-generation transport network requires higher speed and larger capacity. This is not a fiber-optic network, but the development of high-speed backbone transmission also puts new demands on optical fiber.
(1) Expanding the transmission capacity of a single wavelength
At present, the transmission capacity of a single wavelength has reached 40 Gbit/s, and research on 160 Gbit/s has begun. The transmission of more than 40 Gbit/s will impose certain requirements on the PMD of the optical fiber. At the ITU-T SG15 meeting in 2002, the United States has proposed to introduce a new fiber category (G.655.C) for the 40 Gbit/s system, and It is recommended to discuss some of the issues in its PMD transmission, and perhaps a special 40Gbit/s fiber type will appear in the near future.
(2) Realizing ultra long distance transmission
Non-relay transmission is ideal for backbone transmission networks. At present, some companies have been able to use the chromatic dispersion technology to achieve 2000-5000km non-electrical relay transmission. Some companies are further improving the fiber index, using Raman optical amplification technology, can extend the distance of light transmission more.
(3) Adapt to the application of DWDM technology
At present, 32×2.5Gbit/s DWDM systems have been used, and 64×2.5Gbit/s and 32×10Gbit/s systems have been developed and made good progress. The extensive use of DWDM systems places higher demands on the nonlinearity of optical fibers. The ITU-T standard for nonlinear properties and test methods for optical fibers (G.650.2) has recently been completed. When the nonlinear test indicators of optical fibers are clear, the effective area of the optical fiber will be given corresponding indicators, especially for G. The nonlinear characteristics of the 655 fiber will be further improved.
1.2 The subdivision of fiber standards promotes the accurate application of fiber
The World Telecommunication Standards Conference 2000 approved the reclassification of the original G.652 fiber into G.652.A, G.652.8 and G.652.C Class 3 fibers; and the G.655 fiber was reclassified into G.655.A and G. .655.B two types of fiber. The subdivision of this fiber standard promotes the accurate use of the fiber, refining the standard while also improving the index requirements of some fibers (such as the tolerance of some fiber geometry parameters), clearing the different network levels and different Different specifications of the fiber used in the transmission system (such as the PMD value), and proposed some new indicator concepts (such as "dispersion longitudinal uniformity", etc.), have played a very good role in the rational use of fiber. All the proposed changes, the emergence of sub-recommendations, and the drafting of new sub-recommendations mean that there are some improvements in fiber classification and indicators, test methods, or important improvements; they all indicate the need for fiber quality improvement or application direction. The adjustment is notable for the new trend of fiber technology.
1.3 New fiber optics are constantly appearing
In order to meet the needs of the market, the technical indicators of optical fiber are constantly improving, and various new types of optical fibers are constantly emerging. At the same time, major companies are stepping up development of new varieties.
(1) New high-capacity long-distance fiber for long-distance communication
It is mainly a new type of G.655 fiber with large effective area and low dispersion maintenance. Its PMD value is extremely low, which can easily upgrade the capacity of the existing transmission system to 10 to 40 Gbit/s, and facilitate distributed distribution on the fiber. The MANN effect is amplified to greatly extend the transmission distance of the optical signal. For example, Corning's new Pure Mode PM series of optical fibers utilize polarization transmission and composite cladding for DWDM systems above 10 Gbit/s, which is said to be well suited for the development and application of Raman amplifiers. The Teralight Ultra fiber introduced by Alcatel cable has been reported to have a single channel of 40 Gbit/s and a total capacity of 10.2 Tbit/s. There are also some companies that develop negative-dispersion large-area optical fibers, improve the requirements of nonlinear indicators, and simplify the dispersion compensation scheme. They show good performance in long-distance non-regeneration transmission, and long distances in submarine cables. The effect in communication is also very good.
(2) New low water peak fiber for metropolitan area network communication
Metropolitan area network design needs to consider simplifying equipment and reducing costs, and also consider the possibility of non-wavelength division multiplexing (CWDM) applications. The low water peak fiber extends the bandwidth in the extended band of 1360 to 1460 nm, which greatly optimizes the CWDM system, increases the transmission channel, and increases the transmission distance. Some metropolitan area networks may not only require low water peaks of the fiber, but also require the fiber to have a negative dispersion value. On the one hand, it can offset the positive dispersion of the light source optical device, and on the other hand, the negative dispersion fiber and the G.652 fiber can be combined. Or G.655 standard fiber, use it for dispersion compensation, thus avoiding complex dispersion compensation design and saving cost. If Raman amplification technology is adopted in the metropolitan area network fiber in the future, such a network will also have obvious advantages. But after all, the specification of the metropolitan area network is not very mature, so the specifications of the metropolitan area network fiber will change with the change of the metropolitan area network mode.
(3) New multimode fiber for local area network
Due to the rapid development of local area networks and customer premises networks, a large number of integrated wiring systems have also adopted multimode fiber instead of digital cables, so the market share of multimode fiber will gradually increase. The reason why multimode fiber is used is because the transmission distance of the LAN is short. Although the multimode fiber is 50% to 100% more expensive than the single mode fiber, the optical device can be equipped with LED, and the price is much cheaper than the laser tube. Moreover, multimode fiber has a large core diameter and numerical aperture, which is easy to connect and couple, and the corresponding components such as connectors and couplers are also much cheaper. ITU-T has not yet accepted the 62.5/125μm multimode fiber standard, but it is still widely used due to the development of LAN. The ITU-T-recommended G.651 fiber, the 50/125μm standard multimode fiber, has a small core diameter and is difficult to couple and connect. Although it has some applications in some European countries and Japan, it is used in North America. Most countries in Europe rarely use it. In response to these problems, some companies have made improvements to develop a new 5O/125μm fiber-graded (G1) fiber, which is different from the gradient index profile of the traditional 50/125μm fiber core. The distribution has been adjusted to match the use of two windows at 850 nm and 1300 nm. This improvement may find a new market for 50/125 pm fiber in LAN applications.
(4) Air core fiber with uncertain future
According to reports, some companies and university research institutes in the United States are developing a new air-core fiber, that is, light is transmitted in the air of the fiber. In theory, this fiber has no core, reduces the attenuation, increases the communication distance, prevents the interference caused by dispersion, can support more bands, and it allows stronger optical power injection, it is expected Communication capacity can reach 100 times that of current fiber. Some industry players in Europe and Japan are also very concerned about the development of this technology, and more and more research proves that air-core fiber seems to be possible. If it is practical, it can solve the problem of long-distance transmission of existing fiber systems and greatly reduce the cost of optical communication. However, such fibers are subject to many thorny problems, such as fiber stability, side pressure performance, and increased bending loss. Therefore, further discussion on the field use of such fibers is needed.
2 Development characteristics of optical cable technology
2.1 The development of optical networks has led to the emergence of new structures for optical cables.
The structure of the optical cable has always evolved with the development of the optical network and the requirements of the use environment. A new generation of all-optical networks requires fiber optic cables to provide wider bandwidth, accommodate more wavelengths, deliver higher speeds, ease of installation and maintenance, and longer life. In recent years, the development of fiber optic cable structures can be summarized into the following characteristics.
1) The cable structure has a clear choice of fiber type according to the network environment used, such as trunk fiber, metro fiber, access fiber, LAN fiber, etc., which determines the requirements of optical fiber transmission characteristics in a wide range of optical cables. The specific application conditions are also based on the criteria and indicators of the subdivision;
2) In addition to considering the environmental conditions for the use of optical cables, more and more optical cable structures are related to their construction methods and maintenance methods, and must be considered in a unified manner.
3) The emergence of new materials for optical cables has promoted the improvement of optical cable structures, such as the use of dry water-blocking materials, nano-materials, and flame-retardant materials, which have significantly improved the performance of optical cables.
Different occasions and different requirements have led to the development of multiple structures of optical cables. New optical cable structures and various structures that are continuously improved in existing structures are also emerging, and the following types have emerged.
· "Dry cable core" type optical cable: The so-called "dry cable core" is a cable core that is different from the commonly used filling tube type. The water blocking function of this cable is mainly achieved by the combination of water blocking tape, water blocking yarn and coating. Its waterproof performance and water permeability are the same as those of traditional optical cable, but it has some advantages in production, transportation, construction and maintenance. . The first is convenient, because the water-blocking material does not contain viscous grease, and the operation is convenient and safe. Secondly, the dry cable is light in weight, easy to connect, easy to handle, low in equipment investment, low in cost, and clean and hygienic in production and use. Long-term use also reduces the relative movement between the various components in the cable core. Especially in the access network indoor cable and user cable, the benefits are more obvious.
·Eco-optical cable: Some companies have developed eco-optical cables for indoor, building and home based on environmental protection and flame retardant performance requirements. Some materials used in existing optical cables have not met the requirements of environmental protection. For example, PVC emits toxic gases when burned, and lead stabilizers sometimes contain lead, which are harmful to the human body and the environment. In 2001, ITU-T adopted a proposal for L45 - "Minimizing the environmental impact of external equipment on the telecommunications network". It is based on life cycle analysis (LCA) for optical cables, cable optical devices and poles. ) method to determine the impact of the product on the environment. As environmental factors are gaining more and more attention, such indicators for communication external devices, especially optical cable products, have been mentioned on the agenda, and it is difficult to meet environmental protection requirements without working on materials and processes. Therefore, many companies have developed some new materials for such problems, such as the development of a polyamine compound containing flame retardant additives and halogen-free flame retardant plastics for indoor cables.
Submarine cable: Submarine cable has developed rapidly in recent years. It requires long-distance, low-attenuation transmission, and it must adapt to the seabed environment. It is particularly strict against water pressure, air loss, tensile and impact resistance. .
·Marinized Terrestrail Cable (MTC): The shallow-water cable is another type of underwater cable that is different from the submarine cable. It is suitable for installation on the coast and in shallow water without relaying and short communication distance. Underwater (such as between islands, cities along the coast) laid. This kind of optical cable is different from the environment of submarine cable, and requires a small number of fibers (medium), but requires a simple structure, low cost, easy installation and transportation, and is easy to repair and maintain. In 2001, ITU-T proposed the shallow-water cable under the ITU-T G.972 definition, providing a set of specifications for the construction of similar underwater cables, and subsequent formation of corresponding international standards.
Micro-cable: In order to cooperate with the installation of pneumatic installation (or hydraulic installation), various micro-cable structures have been designed and used. For pneumatically mounted miniature optical cables, there is a certain coefficient between the optical cable and the pipeline. The weight of the optical cable is accurate and has a certain hardness. This type of microcable and automatic installation is a promising way for future access networks, especially integrated wiring systems in customer premises networks, such as smart pipes used in smart buildings.
·Cables using nanomaterials: Recently, some manufacturers have developed nanofiber coatings, nanofiber greases, polyethylene (PE) for nano sheathing, and nano PBT for fiber sheathed tubes. The nano-material optical cable utilizes many excellent properties of the nano material, and has certain improvement on the mechanical shock resistance, water blocking and gas barrier properties of the optical cable, and can extend the service life of the optical cable. Currently such materials are still in the trial stage.
·All-media self-supporting optical cable (ADSS): The all-media optical cable has excellent characteristics for preventing electromagnetic influence and lightning protection, and is light in weight, small in outer diameter, and easy to use in overhead. It has been widely used in power communication networks. application. It is estimated that from 2000 to 2005, the annual demand for ADSS cable by the power sector is about 15,000km. ADSS is also a good choice of fiber optic cable types in the telecommunications sector in the environment of anti-electromagnetic interference and thunderstorms. In the future, how to reduce the outer diameter of the ADSS cable, reduce the weight of the cable, and improve its withstand voltage performance are the subject of research and improvement of ADSS cable.
· Overhead Ground Cable (OPGW): OPGW has been around for a long time and has been improving and improving in recent years. PBT is used in the optical fiber unit of OPGW, and a layer of stainless steel tube is added on the outside of the casing. Some of them are also provided with a layer of hot plastic between the plastic sleeve and the stainless steel tube. The length of the stainless steel tube can be tens of kilometers by laser welding. The fiber is fully mechanically protected in such a multilayer protective tube. It is estimated that from now to 2005, the demand for OPGW fiber optic cable will increase year by year, increasing by about 2,500km per year, and by 2005 it is expected to reach 20,000km. Of course, the lightning protection problem of OPGW fiber has always been a matter of great concern to the industry, and should be considered in accordance with the specific environment and conditions of use, so that it is fully protected.
2.2 The automatic maintenance and timely monitoring system of the optical cable has been gradually improved to ensure high-capacity and high-speed optical cable transmission without interruption.
Maintenance of fiber optic cables is important to ensure the reliability of the network. In the opened optical network, the maintenance and monitoring of the optical cable should be carried out without interrupting the communication. Generally, the state of the in-use optical fiber is detected by monitoring the idle optical fiber (dark optical fiber), and the more effective way is directly Monitor the fiber being communicated. Although ITU-T has collected and discussed internationally up-to-date information for a long time, the L.25 Cable Network Maintenance Recommendation was issued in 1996, which provides detailed maintenance scope and functions for preventive maintenance and post-failure maintenance of optical cables. However, the current needs are no longer met. The latest proposal is the “Maintenance Monitoring System for Optical Cable Networks” (recommendation L.40) adopted by the IUT-T SG16 meeting in December 2001. In order to further shorten the detection and repair time, Lucent has proposed a new generation of fiber testing and monitoring system, which can issue a fault alarm within 1 s, find the fault point within 3 minutes, and the staff can operate remotely. It is said that the system will also be developed. Fault prediction and rapid response to fiber breaks (cables). Telecommunications companies in Japan, Italy and other countries have also proposed some system programs.
· Japan NTT solution: The use of fiber optic selectors in the office to connect with the test equipment and transmission equipment of the system to form a system that can monitor the condition of the fiber in real time, ensuring that the useful signal is transmitted on the fiber through the fiber optic selector test. The faulty fiber can be pre-selected and sent to the maintenance center for proper processing in time to avoid the bad condition entering the useful optical transmission channel, thereby supporting the entire optical communication system during operation; passing the water sensor outside the office The device can monitor the position of the external equipment optical cable connector box immersed in water, the water sensitive sensor is installed on the idle optical fiber, and the water sensitive sensor is provided with water absorbing expansion material, and when the water penetrates the joint box, the water absorbing material expands to make the joint box The fiber in the medium is forced to bend, so that the loss of the fiber is increased, which is reflected in the OTDR of the monitoring center.
·Italian solution: This solution is a new continuous cable monitoring system. The main feature is the integration of cable network, fiber optic cable and cable jacket monitoring. It not only uses the OTDR system to periodically monitor the attenuation of the fiber, but also detects the attenuation changes, alarms, and locates the fault. Monitor the integrity of the cable jacket, including the monitoring of the insulation resistance of the sheath to the ground, and immediately identify the problem (such as the water in the jacket), so as to achieve a more comprehensive notice of the failure.
Comparing the schemes of the optical cable maintenance support system proposed by the Japanese and Italian telecommunications departments, the Japanese scheme adds a fiber optic selector to the OTDR to automatically test the optical fiber, and installs a water-sensitive sensor on the outer line and monitors the sheath to form a A complete set of automatic maintenance and support systems can truly maintain the maintenance of optical communication. In addition to monitoring fiber performance, the Italian solution also considers automatic monitoring of sheath insulation resistance. From these two examples, it can be seen that the maintenance of fully automatic fiber optic cable should be a development direction.
3 Development characteristics of communication cables
3.1 Broadband HYA communication cable needs to better serve new digital communication services
Although the original cable network can support some digital new services, it is not particularly ideal in practical use, and there are still certain restrictions on communication distance, speed and quality. For the new network, of course, it is based on optical fiber. For areas where the fiber cannot be reached or where the cable network is still to be built for various reasons, the new broadband structure HYA cable (copper core polyethylene insulation integrated sheath) should be considered. Communication cable) to better meet the needs of new business development. Some companies have tested the high-frequency characteristics of existing cables. They have concluded that the cable under study (that is, the existing HYA local cable) cannot meet the technical requirements of Category 5 cable, and the outdoor cable must realize the characteristics of Category J cable. Must be achieved through special design and manufacturing. However, below 20MHz, all cables show adequate transmission performance.
In 1997, the United States developed the standard for twisted communication cables for broadband (ANSI/ICEA S-98-688-1997 and S-99-689-1997), including both unfilled and filled versions. The transmission bandwidth has been extended to 100MHz for use in digital networks. The IEC has also discussed this issue for a long time. In 2001, IEC 62255-1 "Multi-logarithmic cable for high-bit frequency digital access telecommunication network" proposed 0.4 to 0.8 mm wire diameter, 1 ~ The proposal of 150 pairs and the highest frequency of 30MHz, this proposal may open up a new space for this kind of cable. China has also started to explore and develop this aspect, and is setting up corresponding standards.
3.2 Super Category 5 and Category 6 cables will replace Category 5 cables as the development of wiring systems.
With the increasing demand for broadband wiring in intelligent buildings and intelligent building communities, Super Category 5 and Category 6 cables have gradually become the mainstream in the wiring system. The frequency bands of Category 5 and Category 5 cables are both 100 MHz, but they have the capability of two-way communication, allowing users to simultaneously send and receive broadband information. Therefore, the Category 5 cable has improved resistance unbalance, insulation resistance, capacitance imbalance to ground, transmission speed, etc., and increases the near-end crosstalk attenuation power and the iso-level far-end string. Some indicators such as sound power, so some improvements in process and structure can be achieved. On the basis of the Category 5 cable, the Category 6 cable has increased the transmission frequency band to 250 MHz, and its corresponding indicators have also been greatly improved. At the same time, Category 6 cables require not only strict processes, but also many manufacturers have certain improvements and innovations in the structure, such as the use of foamed leather insulated core wire or leather foam insulated core wire, skeleton structure isolation line pairs have improved The high frequency characteristics of the cable.
3.3 Physical foaming RF coaxial cable and leaky coaxial cable will have a good development prospects
Due to the rapid development of mobile communications, physical foaming RF coaxial cables for radio bases, especially for ultra-flexible indoor cables and routing cables, have a large market demand. At the same time, as the coverage of mobile communication signals continues to expand, the number of base stations increases, and the requirements for mobile signals in the edge areas (elevators, subways, underground buildings, high-rise buildings, etc.) continue to increase. It is expected that such cables will have Better development prospects. However, the requirements for cable indicators (such as standing wave ratio, shielding loss, etc.) have been significantly improved, and the process and structure of the cable should be continuously improved to adapt to it.
4 Fiber optic cable and communication cable technology and industry development issues worth considering
4.1 Actively innovating and developing new technologies with independent intellectual property rights
Although China's optical cable technology has developed greatly in recent years, some technologies with independent intellectual property rights are already playing a role, but it should be seen that this ratio is still very small. There are nearly 200 fiber optic cable factories in China, but Most of the products are single, have no independent intellectual property rights, and have low technical content and low competitiveness. According to statistics, there were 132 domestic enterprises applying for optical communication patents from 1997 to 1999, including 38 optical fibers and 19 optical cables. In the same period, foreign companies applied for 550 optical communication patents in China, including 37 optical fiber cables. There are also reports that since 1997, the domestic optical communication core technology patents are 90, and only 9 of China's independent applications, accounting for only 10%. In fact, China's fiber optic cable technology should be said to be far from the international level. Therefore, as the world's second largest optical cable country, we should develop technology with independent intellectual property rights as the top priority of our work, and strive to create more. Patented fiber optic cable.
4.2 Develop new products with advanced technology, compatibility with the use environment and construction technology
As the telecommunications network continues to evolve, new requirements are constantly being placed on fiber optic cable products. It is not difficult to find that the structure of the optical cable is increasingly dependent on the environmental conditions used and the specific requirements of the construction. In the development of submarine cable, shallow water cable, ADSS and OPGW cable, this will have a deep understanding. In the future, the focus of fiber optic cable construction will continue to expand with the construction of access networks and customer premises networks. The new generation of fiber optic cable structures and construction techniques will also be based on, for example, micro-cables, insufflation or floating installations, and mini-microtubes or tubule systems. A full range of technologies and a series of new changes, so that limited space can be fully and flexibly utilized. This also includes a number of new technical issues in fiber optic cable design, manufacturing processes, fiber optic cable materials, and construction and installation. Some countries or companies have gained some experience and are gradually forming new system technology patents. There are many users in China, and the access network and customer premise network have many characteristics, and there are more requirements for accessing optical cables, which provides a good opportunity for us to research and innovate the access network and the customer premises network cable structure. should say,
Most of the fiber optic cable technology is behind the latest technology in foreign countries. Although it is closely followed by advanced technology, there are too few components for self-innovation. In the future, we should make some efforts in this area and take our own path of innovation. In the access network with Chinese characteristics and the customer premises network, some optical cable products with Chinese characteristics are used.
4.3 Utilize existing equipment and technology to improve the corresponding characteristics of HYA local cable and provide better services for digital services
For copper cables that have already been laid, we can only use the features to open digital new services under existing conditions. While the existing HYA cable can also open some new services such as ADSL, the capacity is limited. When the number of ADSL increases to a certain limit, interference problems will occur, and the previously opened services will also be affected. Therefore, for the newly laid copper cable, it is hoped that some new broadband indicator requirements will be put forward to prepare for the opening of more and better new services in the future. Existing local cable manufacturers should thoroughly study their own production processes, carefully design and elaborately without changing (or changing) production equipment, and improve the technical level of existing cables to provide a higher level. Broadband cable provides a high quality channel for more and better development of digital new services.
4.4 Improving the construction and maintenance methods of optical cable
At present, in order to adapt to the characteristics of urban construction, the international focus on the construction of light and cable without digging trenches, the use of small trench or micro-dished technology to install optical cable, and automatic monitoring of the optical cable network to ensure that the optical cable network does not interrupt communication maintenance. Corresponding to this is the need to develop the corresponding components, tools and equipment, and to make some improvements in the system to adapt to it. The ITU has attached great importance to the development of water-immersed sensors for optical cables, fiber optic selectors for automatic fiber testing, and the 1s alarms proposed by the United States, the positioning indicators within 3 minutes, and the comprehensive monitoring of fiber-optic cores and cable jackets proposed by Italy. These methods have already played a significant role in modern optical networks. It can be seen that in order to ensure the reliability of the work of the optical cable network, reduce costs, save labor and save time in construction and maintenance, gradually promote new construction methods, gradually improve the automatic monitoring and maintenance system of the optical cable network and improve the uninterrupted optical cable network. Maintenance levels are imperative.
4.5 Calmly review the development of the current telecommunications market and promote the development of fiber optic cable and communication cable industry
Since the second half of 2001, the demand for fiber optic cable has declined, which of course has a lot to do with the overall decline of the world telecom industry and the bursting of the broadband network bubble, but more is due to the shortage of fiber optics since the second half of 1999. The company's expansion has had too much impact. According to the data, in 2000, the global fiber manufacturer's investment reached 2.6 billion US dollars, six times that of 1999. According to projections, the global fiber production capacity will reach 1.65 to 175 million fiber-optic kilometers in 2002, far exceeding the actual demand. . Coupled with the current telecommunications infrastructure downturn, the phenomenon of excess fiber is inevitable.
Although the market trend of fiber optic cable and communication cable has been affected by the development of the international economic situation, especially with the development of the entire telecommunications industry, it should be seen that after extruding the water of the network bubble, along with the fiber The network will grow from the expansion of the backbone network to the expansion of the access network, metropolitan area network and the extension of the customer premises network. The market for fiber optic cable and broadband digital cable is bound to grow. According to KMI, the world fiber market will start to grow significantly in 2003, and the market size in 2004 will exceed the highest installed volume in 2000.
It should be noted that the information and communication industry is a sunrise industry full of vitality and vitality. The network economy has a strong vitality. The development of information technology and network technology is still an important driving force for social progress. Information network is still the world economy today. A strong trend in social development. Therefore, we should build confidence and seize opportunities under the favorable conditions of global economic improvement, communication market recovery and the development of western China to promote greater progress in fiber optic cable and communication cable technology and industry.
4.6 Grasp the great opportunity of the development of the western region and develop optical cable technology and industry
The development of the western region is a major strategy of the country. The state has formulated favorable policies and the government has also given strong support to the development of communications and other industries. The west is a region with a complex geographical area, a wide distribution, and relatively backward communications. In the economic development, communication must be advanced, and some advanced products of fiber optic cable and communication cable are needed to meet the needs of development. Therefore, qualified products will find a good market here. Huge projects such as West-East Power Transmission and West-East Gas Transmission also require a large number of high-quality ADSS, OPGW and other types of optical cables and various cables. Therefore, various technologies, products and achievements of fiber optic cables and communication cables will be exerted in the development of the western region. At the same time, the construction of western modernization has raised many new problems for our products. The fiber optic cable and cable industry will also have better opportunities for transformation and innovation while developing the Great Western Region, and promote the upgrading and development of its own technical level.
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