On the fiber optic cable and communication cable technology

First, the characteristics of optical fiber technology

(a) The development of fiber optic network with new requirements. Next Generation Network (NGN) led to a number of views and controversy. Some experts predicted that, regardless of how the development of next-generation network
network must be to reach the three worlds that the service level of Ⅳ world, passing the light of the world level and access level of the wireless world. Next-generation transport network requires higher rates, greater capacity, which is none other than non-fiber optic network.

1, expanding the transmission capacity of a single wavelength. At present, the transmission capacity of a single wavelength has been reached 40Gbit / s, and has started 160Gbit / s of study. 40Gbit / s transmission over fiber PMD will be made on certain requirements, in the near future there will be a dedicated 40Gbit / s optical fiber type.

2, to achieve ultra-long haul transmission. No relay transmission is the ideal backbone transmission network, at present, some companies have been able to use homogeneous dispersion management technology, 2000-5000Km non-relay transmission. Some companies are to further improve the optical indicators, the use of Raman amplification, optical transmission can be extended greater distances.

(B) of sub-standard optical fiber for the accurate application. 2000 World Telecommunications Standards Assembly re-divided into the original G.625 fiber G.625A, G. 652.8 and G.652.0 three types of fiber, the G. G. 655 fiber is divided into re- 655. A and G. 655. B two fiber. This contributed to the breakdown of the standard optical fiber using the exact, detailed criteria also increased the number of fiber target, and proposed some new indicators of the concept of rational use of optical fiber made of a very good role.

(C) of the new fiber in the emerging. In order to adapt to market requirements, fiber optic continuous improvement of technical indicators, a variety of new optical fiber in the constantly emerging, while large companies are stepping up the development of new varieties.

1, for the new high-capacity long-haul long-distance communications fiber. Mainly because some large effective area, low-maintenance new G.655 fiber dispersion, the PMD value is very low, you can make the capacity of existing transmission systems to easily upgrade to 10-40Gbit / s and to facilitate a distributed Raman fiber effect amplification, the optical signal transmission distance is greatly extended.

2, a new type of communication for metropolitan low water peak fiber. MAN need to consider simplifying the design of equipment and reduce costs, also need to consider non-wavelength division multiplexing (CWDM) application possibilities. Low water peak optical fiber in the 1360 - 1460nm band extension of the bandwidth has been greatly expanded, making CWDM system is highly optimized in the ground, increasing the transmission channel, an increase of transmission distance.

3, for LAN's new multi-mode fiber. As local area networks and the rapid development of CPN, a large number of integrated wiring has also been adopted to replace the digital multi-mode fiber cable, multimode fiber thus market share will gradually increase. Multimode fiber was selected because the local area network transmission distance is shorter, although the single-mode fiber multimode fiber expensive than the 50% --- 100%, but they are supporting the use of light emitting diode devices, grid is cheaper than the laser tube many, and multi-mode fiber has a larger diameter core diameter and numerical space, easy connection and coupling, the corresponding connectors, couplers and other components of the price is much lower.

4, the uncertainty of the hollow fiber. According to reports, some U.S. companies and university Research institutes in the development of a truly new hollow fiber, that fiber alone in the air transmission. If practical, we can solve the existing problem of long-distance transmission fiber optic systems, and greatly reduce the cost of optical communication.


Second, the fiber optic cable technology features

(a) makes the development of fiber optical networks are emerging new structure. The development of fiber optic cable structure can be summarized as the following characteristics:
1, fiber optic cable structure based on the use of the network environment with a clear choice of the type of fiber, such as fiber optic backbone network, metropolitan optical fiber, optical fiber access, fiber optic local area network, etc. This determines the transmission characteristics of optical fiber within a wide range of requirements, the specific conditions of use can be broken down according to the standards and indicators.

2, optical fiber cable structure, consider the use of environmental conditions than other, more and more of its construction method, maintenance method is related to the same considerations, supporting the design.

3, the emergence of new materials, optical fiber, optical cable for the improvement of the structure such as dry-type water blocking materials, nano materials, such as the use of flame retardant material, so that cable performance improved significantly.

(B) the automatic maintenance of fiber optic cable, timely monitoring system has been gradually improved, to ensure high-speed large-capacity fiber optic cable does not interrupt transmission. To guarantee the maintenance of fiber optic cable network reliability is very important. Has been opened in the optical network, cable maintenance and monitoring without interrupting the communication should be carried out under the premise, usually by monitoring the free fiber (dark fiber) way to detect the state of the optical fiber, a more effective way is to direct Monitoring is the fiber communications. The latest proposal was in December 2001 adopted by the TUT-TSGl6 "cable network maintenance monitoring system" (L40 recommended). Lang has made the U.S. a new generation of telecommunications companies fiber testing and monitoring system, a fault in the warning 1s, 3min to find the point of failure, and the staff can remote control operation, said to have failed the system will also develop prediction and the broken fiber (cables) of the rapid response capability.

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