The Research And Manufacture Of New Type Of Wideband Optical Fiber

With the rapid development of internet technologies, an increasing transport capacity through optical fiber transmission system is needed. Facing the demand of increasing transport capacity, there are three methods to meet it at present: the 1st way is to increase transfer bit rate of single channel; the 2nd way is to reduce the spacing between adjacent channels; the 3rd way is to increase the bandwidth of transmission system. The first method will face the new problems of dispersion compensation as transfer bit rate of signle channel gets 10Gbit/s or more, and the electronic system has so-called'electonic bottle neck'effect as transfer bit rate increases more. The second method will face nonlinear effect such as FWM, as the spacing between adjacent channels is decreased from 100GHz to 50GHz or 25GHz, at same time, there needs wavelength stabilization technology. So the third method is the most potential way to increase the transport capacity of system effectively. To increase the bandwidth of transmission system, one side, we need develop new type of laser resource (for example, L band EDFA extend its operating wavelength range from 1530 ~1560nm to 1570 ~1605nm, its amplifying gain bandwidth increases double); on the other hand, we need increase the bandwidth of optical fiber, i.e. the wavelength width of operating band.G.655 optical fiber needs dispersion compensation on L band even it only transfers 80km long. Zero dispersion points of part of G.655 optical fibers are on the S band, nonlinear effects like FWM will be serious problem as DWDM technology is applied on this band. By this reason, these kinds of optical fibers are not suitable for using DWDM technology on S band, so G.655 optical fibers are only designed for DWDM applied on C and L bands. The bandwidth of G.652 optical fiber is biggest in all kinds of transport optical fibers, but its high dispersion values on C and L bands limit the transport distance without dispersion compensation. Dispersion management in 10Gbit/s or more DWDM system is critical. The more the channels are or the narrower the spacing between adjacent channels is, the more strictly the dispersion accumulated by the system transported a certain distance are. Big dispersion value of G.652 optical fiber will increase the frequency of dispersion compensation; more frequency of dispersion compentstion will certainly cause higher cost. Big dispersion slope of G.655 optical fiber will add the difficulty of dispersion compentsation, higher difficulty of dispersion compensation will also increase the cost.G.656 optical fiber is specially designed for using DWDM technology on S, C and L bands; the optical fiber have overcomed some defects of G.655 optical fibers and G.652 optical fibers. It has enough dispersion value on S band to restrain effectively nonlinear effects such as FWM; it has same dispersion level with G.655 optical fiber, it can be applied in long haul network and metro area network. Aim at the future trend of optical fiber communication technologies and based on the standard of ITU-T G.656, one new type of wideband optical fiber was developed. The new fiber has excellent dispersion performance, the minimum dispersion coefficiency from wavelength 1460nm to 1625nm is greater than 2ps/ (nm km), and the maximum is between 14 ps/ (nm km). The effective area at 1550nm is between 52～64μm2. Relative high dispersion and moderate effective area can restrain effectively nonlinear effect, such as FWM (four-wave mixing) etc. The relative dispersion slope of the optical fiber is excellent, it is much lower than that of G.655 fiber and it is same or less than that of G.652 optical fiber. The dispersion is much lower than that of G.652 fiber it is little higher or same level than that of G.655 fiber. Low dispersion and low slope is helpful to realize full dispersion compensation with lower cost. The optical fiber has also excellent attenuation performance, in which the water peak caused by OH absorption is almost removed by use of advanced PCVD process. The attenuation from 1310nm to 1650nm is less than 0.4 dB/km, attenuation at 1550nm is less than 0.22dB/km. In addition, it has also excellent mechanical performance and geometry performance.Combination with experiments of new type of wideband optical fiber, some basic theory of fiber manufacture, process control ruler and measurement method are introduced in this paper, a lot of experimental data was analyzied. Besides these, the paper also describes:(1) Basic theory of communication optical fiber was introduced simply in this paper, dispersion compensation technology in DWDM system and concept of nonlinear effect are described.(2) Based on the theory of numerical simulation of optical fiber and using CAD technology, the profile design of new type of wideband optical fiber was accurately calculated with Fiber_CAD software. A lot of calculation results can be used for manufacture instruction of these types of optical fiber.(3) The processes of optical perform making and optical fiber drawing are described; how to optimize the performance of optical fiber was introduced by the annlyzation of main factors of PCVD process and drawing process.(4) The results of new type of wideband optical fiber are analyzed by some optical fiber theorys.(5) The results of new type of wideband optical fiber on 40Gbit/s DWDM are described.