Next generation optical fiber selection of reference

 Except for a few years ago it was widely believed, developed trunk cable construction has been basically completed. However, nearly two years IP business explosion caused by the huge demand for network capacity, leading to a new round of climax of construction of fiber optic trunk cable. In North America at present many trunk cable routing capacity is exhausted, the maximum section capacity demand has begun to develop in the direction of Tb / s, once again become the shortage of demand for transmission capacity. Therefore, many far-sighted telecommunications companies especially those emerging telecommunications company launched a new round of large-scale construction of fiber optic cable network climax. Its characteristics are all using a new generation of G.655 fiber, and has a very high density of optical fiber. According to statistics, in recent years, the new application of G.655 fiber length is more than 11000000 km, has been far more than the traditional G.652 fiber. These new networks using the latest technology, high capacity, low cost, is the traditional network from 10% to 50%, in infrastructure formed the traditional telecommunication companies an important competitive advantage.

In recent years, the telecommunication network in China present situation of rapid development, the demand for telecommunication services lasts high speed grows, telephone network scale has been ranked second in the world, cellular mobile communication network scale is ranked third in the world. By the end of 1999, the national telecommunications network scale has more than 160000000 doors, trunk cable length of 220000 km, telephone penetration rate of 13%.

According to preliminary estimate, China's main maximum cross section capacity over the next 10 years may reach 600Gb / s～ 1Tb / s, the development potential of large.

Optical fiber is a foundation, must account for 15～ 20 years life period can still meet the transmission capacity and rate of development needs, so that the optical fiber selection in some sense than the equipment selection is more important, more need to have strategic eye and prospective. From our future business development needs, our country east Shinkansen construction will gradually shift to 10Gb / s rate based WDM system. At this rate under the premise, although G.655 fiber itself price is still G.652 fiber 2.5 ~ 3 times, but the cable after the price only increased 30% to about 70%, whereas in dispersion compensation on savings made by G.655 optical fiber system cost than the traditional G.652 fiber optic system cost about 30%～ 50% therefore, new dressing fiber steering G.655 fiber is decision-making have farsightedness. On the other hand, our country is an economic development highly unbalanced state, the western region of China's business needs in a long time are difficult to catch up with area of the eastpart part, and using 2.5Gb / s rate based WDM system will be sufficient to meet the very long time the main traffic demand.

As for the specific G.655 fiber selection, needs to consider many factors, such as whether the effective support for 10Gb / s and 40Gb / s transmission, can effectively support the C band and L band transmission, optical fiber system, optical fiber system total cost, existing the fiber production record and process stability, there is no an affirmative answer, one thing is certain, the first generation of true wave fiber and LS fiber do not have to take into account, and the second generation of the true wave RS optical fiber with large effective area fiber in performance are sufficient to support our future for at least 15 years in the capacity and speed of development.

From the network perspective, in order to adapt the future multiple service multiple rate environment demand, expanding the available spectrum range, new dressing fiber gradually shift is roughly equal to the price, and the available spectrum range can be extended 100nm without water peak fiber is logical.

Optical access network technology

According to Forrester Research estimates, in the next two years half the business users to be bandwidth doubling. Then the bandwidth from why and come? Enterprise user is currently only a few options: bandwidth constrained T1 line or is expensive and is not popular T3 line.

Optical fiber is the solution to this problem. According to the Vertical Systems Group said, at present only 3% businesses connected to the optical network, at the same time 76% enterprises from the optical fiber network distance in miles ( about 1.6 km ). However, until now, the optical fiber is connected directly to the enterprise is the only way to use the expensive SONET equipment, it is possible to optical fiber is connected to each building.

A new network technology -- optical access network technology ( OAN ) is to remove the barrier in LAN and WAN increasing capacity bottleneck practical technology. OAN allows service providers to businesses of all sizes to fiber based broadband services. Based on the passive optical network ( passive optical network, PON ) OAN does not need to be installed in the external station precious active electronic equipment, so that the service provider can be cost-effective to provide the necessary bandwidth.

OAN consists of three parts: one is installed in the service provider the central office of the optical access switch ( OAS ); a mounting in the client's intelligent optical terminal ( IOT ); and a mounting in the above two kinds of equipment between the PON. In the PON environment in addition to fiber optic lines only required external equipment is low ( a few hundred dollars ) passive optical splitters and couplers. These two kinds of equipment can be like water pipes of T shaped connector as isolated or combined transport stream: the half of the light transmission in one direction, the other half to another direction. Coupler / splitter can be seen in many optical components manufacturers to buy.

OAS is a kind of from distribution in the PON " downstream" hundreds of IOT transport stream pooled IP/ATM switch, standard interface of OAS provides an effective entry point into the wide area network. While the pizza box size IOT is a low-cost client device, it can support voice and broadband data services.

In an access network, a specification can not satisfy all the needs, the T1, T3 and digital subscriber line is such a case. OAN enables business users can enjoy a variety of flexible bandwidth: from 1M to 100Mbps and special wavelength bandwidth. In addition, OAN enables business users can quickly improve the bandwidth to support them on bandwidth demand changes, for example, a retailer in the holiday season will be the service level from 3M to 10Mbps.

Since few companies ready to use occupy the entire wavelength services, so the OAN application can be divided into smaller wavelength wavelength is very important. As the dense wavelength division multiplexing technology can increase the optical fiber line wavelength quantities, segmentation wavelength capacity was increased by a wavelength which can provide a service endpoint number. In this function, service providers do not require customers to submit to each wavelength when a lot of investment.

OAN is another key attribute is the use of embedded fiber optic infrastructure. Through the outer stations using passive optical splitter and a coupler, the service provider only in the office area near the deployment of small optical fiber line, and then by the office area to radiate out for the majority of business customers.

Submit high capacity bandwidth fiber optic infrastructure will eliminate the public network in the last kilometer obstacle. With the famous chicken-and-egg question like, enterprise users have unrestricted access to the Internet, will enjoy a virtual private network, business to business e-commerce and application of outsourcing in next generation service.