Analysis of future development direction of fiber optic cable technology

Fiber optic cable is an indispensable part of the "broadband China" construction, and its technology development trend has been concerned and studied by industry experts. Recently, some experts from the front line of operators have expressed their views on the application of fiber optic cable new products developed by FiberHome Communications in actual projects. This “behavioral interaction of operations and manufacturing” is conducive to the timely development and production of equipment suitable for operators. Network fiber optic cable products. They are now summarizing their views, hoping to provide useful reference for the construction of optical fiber networks for operators around the country.

Air blown micro cable technology booster

China Mobile builds a smart optical network

As a new and mature optical fiber network construction technology, the air blown microcable technology provides an excellent solution to solve the bottleneck problem of pipeline resources faced by China Mobile, and will help China Mobile build a smart fiber network in the future.

After being introduced into China in 2001, air blown microcable technology has been applied in long-distance networks, metropolitan area networks, and access networks in China after more than ten years of development. Moreover, with the application and development of this technology in the country, relevant pipes, fittings and construction services have been realized in domestic commercialization, and there is no longer any obstacle in the application of technology.

In recent years, with China Mobile’s full-service operations, large-scale construction of FTTH, large-scale 3G deployment, and 4G deployment, the increase in China Mobile’s traffic volume has increased the demand for fiber optic cables in metropolitan area networks. However, due to historical reasons, China Mobile has a limited amount of metropolitan pipeline network resources, and in the context of the municipality's inability to excavate roads to build new metropolitan pipelines, China Mobile’s shortage of metropolitan pipeline network resources is becoming increasingly serious. Find spare pipes to lay new cable routes. Under such a realistic condition, full use is made of the remaining space in the pipeline where the optical cable has been laid, and a micropipe is manually pulled in the pipeline, and then the microcable is blown into the micropipe by the air blowing technology, and the metro cable can be easily realized. Capacity expansion and fiber access.

In the pipeline where the optical cable has been laid, using this solution to utilize the remaining space has three advantages compared to directly pulling and laying a new cable in the remaining space:

(1) Since the micropipes are of small mass and good bending performance, it is easier to manually place the micropipes than to manually pull the pipe cables, which can reduce the construction difficulty, increase the construction efficiency, save the construction cost, and shorten the cycle.

(2) Due to the unique advantages of the air-blown microcable technology, in the case of micropipes and pipe cables with the same outer diameter, the microcables can be air-discharged in the micropipes with a greater number of cores than the cable of the pipeline. Increase the pipe core density in the remaining space.

(3) Since the construction difficulty of artificial traction microtubes is even lower, and the microcables are all in the micropipeline during construction and after construction, the protection of already installed optical cables and microcables is better.

Therefore, to make full use of the remaining space in the pipeline where the optical cable has been laid, first manually hauling and placing a micro-tube, and then blowing the micro-cable into the micro-tube is no doubt an excellent solution to solve the problem of shortage of pipeline resources currently facing China Mobile.

However, although air blown microcable technology is an excellent and mature solution to the shortage of pipeline resources, as a new technology, there are also some specialities in its application. For example, professional air blowers and equipment are required for construction. The size of the microtubes should be uniform and the inner wall should have a silicon core lubricant layer and a diversion groove; fittings should use matched size devices; and the microtubes and the microcables should be fixed separately and then be blocked in sections. As the air blown microcable technology has just begun to be applied in large scale in China, the construction team of many operators does not understand these special features and does not have the corresponding construction equipment and conditions. Therefore, the author proposes that China Mobile should use the air blowing microcable. The technology should adopt a tender mode of a package of services to allow fiber cable manufacturers to provide a package of services for microcables, pipes, fittings and construction to fully utilize the advantages of air-blown microcable technology and solve the problem of shortage of pipeline resources faced by China Mobile.

In addition, the air blowing performance of the microcable is a key indicator of air-blow construction, while the air-blowing performance of the microcable is determined by the interaction of the microcable, tubing and air blower. When operators of certain provincial and municipal companies apply air-blown microcable technology, they often tender micro-cables, pipe materials and air-blasting construction services separately, resulting in poor performance of micro-cable air-blowing during construction and cannot fully define the corresponding conditions. Responsible party. However, if a blanket service bidding model is used to apply air blown microcable technology, allowing cable manufacturers to provide a full range of solutions can solve this problem.

A few days ago, Guangdong Mobile has launched a tender package service using air blown microcable technology. The inspection of the early-stage bids shows that Fiberhome Communications can provide an excellent air-blown micro-cable technology package service solution. Its pipes, fittings and construction services are all imported from abroad, and the air-blowing performance of the micro-cables has been tested by foreign professional air blowers. Institution testing, air blow performance is very good. (China Mobile Design Institute Tang Hongju)

Low Loss Fiber Applications in High-Speed ​​Transmission Systems

Optical fiber is the cornerstone of modern information networks. As a key component in an optical communication network, the transmission performance of the optical fiber directly affects the development of the communication system.

With the gradual resolution of key technologies for high-speed transmission such as polarization-multiplexed phase modulation, DSP-based digital coherent reception, and third-generation super-error-correction coding, WDM100G systems began to be deployed in 2013, and wavelength dispersion and PMD are no longer Important limitations. However, the nonlinearity of the fiber is determined by the nature of the material, and it is very difficult for the system to compensate. In order to increase the fiber input power, the current consideration is to further increase the effective area. The new large-mode fiber in the industry can increase the effective area by 70% when the dispersion is less than 20ps/nm/km, which has a significant effect on extending the transmission distance and increasing the OSNR.

At present, G.652 fiber is still the mainstream type, and the soft-judgment technology provides a long-span indicator of 14×25 dB or more for the WDM100G system, making the low-loss performance become the relentless pursuit of this most common fiber type. China's optical fiber manufacturers such as FiberHome, Fortis, Changfei, Hengtong, etc., after years of technological improvement and practical accumulation, can mass production of G.652D optical fiber better than 0.185dB/km, continue to maintain the world's best price. FiberHome's optical fiber preforms have a leading edge in terms of low-loss, and in collaboration with the unique fiber processing technology of the bonfire, it further reduces the attenuation coefficient of the fiber and provides users with a practical transmission capability of over 1200km without relay.

The rate of 400G or even higher needs to reduce the nonlinear effect of high-speed transmission by increasing the area of ​​the mode field, reduce the accumulation of ASE noise introduced by the OA through ultra-low loss, can increase the fiber input power and effectively extend the transmission distance, so on the current fiber It is costly to implement long-distance transmission. This area will be the stage for future new fiber with a mode area of ​​130 μm2, attenuation of 0.17 dB/km, and non-linear coefficient of 0.8 w-1*km-1. However, commercial products that meet these three criteria have not yet emerged. The dispersion of such large-diameter fibers may no longer be the main indicator, but the working environment is more demanding and may even affect the structure of the main cable. The new fiber is complemented by a Hybrid Noise or Raman OA with a smaller noise figure, which in turn enhances the performance of the line system and is a visible choice for the 400G+ rate.

In view of cost and revenue pressures, it can be predicted that China’s leading operators will only consider large-scale deployment of new-generation optical fiber varieties under the premise of reliable and reliable high-speed transmission technology, a breakthrough in network data interface speed, and maturity of new optical fiber products. It will not overbuild ahead of the basic physical network. Low-cost and stable G.652D products and low-loss optical fiber derived from this guarantee 100G speed deployment without increasing costs. With the high-quality optical fiber material structure and superb maintenance and management level, it is still pragmatic for operators to enhance profitability. And wise choices.

Circular introduction of optical fiber cable in the promotion of FTTH construction

With the expansion of modern society's information and soaring demand, users are increasingly demanding transmission rates and transmission bands. Broadband network construction and smart buildings are also rapidly developing. In order to meet the needs of development, all countries in the world are carrying out FTTH construction and promotion on a large scale.

FTTH fiber optic cable is indispensable for construction. As the introduction of optical fiber for communications, due to the differences in building structure, laying method and application environment, it will inevitably bring about differences in the cable structure and performance requirements.

At present, in China, a large number of butterfly optical cables are used in the introduction of optical cables for communications. The cost of butterfly-entry optical fiber cable is low, but it has the following disadvantages: 1. The structure is not very reasonable, the optical index is easily affected, thus affecting the use and product life; 2. The indicator redundancy is small, such as tension indicators; 3. Application scenario Limited, especially not suitable for outdoor use, not suitable for use in narrow laying spaces or pipes.

More fiber optic cables must be developed that meet the structural and performance requirements in order to increase the reliability and suitability of users to introduce fiber optic cables. Under such background conditions, Fiberhome Communications first proposed the concept of circular cable introduction, and developed several types of circular cable for introduction, and cooperated with China Telecom Group Corporation Jiangsu Branch to carry out a large number of trials and tests in actual projects. verification. The results show that the circular introduction of optical fiber cable overcomes a lot of quality risks, is more suitable for use in more occasions, and also proves the feasibility of a large number of circular introduction of optical fiber cable and practical application. The Jiangsu branch had been used commercially in the second half of last year and has so far purchased more than 20,000 kilometer-km. The branch office in the city has reported very good results. The amount of circularly introduced fiber optic cable has begun to exceed the amount of fiber optic cables used in the butterfly.

Circular introduction of optical fiber cable is uniform, symmetrical, soft, and easy to peel. Various mature technology is mature. It is superior in tensile, twisting, bending, crack resistance and solar radiation. In the case where the cable is required to have a greater tensile strength in the penetrating pipe, in the narrow installation space or in the pipeline, in the case where the cable is required to be flexible and the bending radius is small in the installation environment and in wet and humid environments, the circular introduction cable may be preferentially used. Placed.

In order to better regulate the manufacture, inspection, procurement and application of circular incoming optical cables, FiberHome is drafting circular introduction of optical cable industry standards and related technical specifications.

It can be foreseen that the round-input optical fiber cable will surely get a lot of promotion and application in the construction of FTTH, and the matched devices, engineering, and design will also get a lot of development and application.