The Advances of fiber technology can be explained in two ways: one is the communication system optical fiber, the other is special fiber.
There are only three fiber transmission window earlier: 850nm (first window), 1310nm (second window) and 1550nm (third window).
In recent years have developed a fourth window (L-band), the fifth window (full-wave fiber), and S-band window. The anhydrous peak full-wave window is the particular importance develoment . Huge significance for the successful development of these windows is that from 1280nm to 1625nm broad optical frequency range, can achieve low-loss, low-dispersion transmission, the hundred times transmission capacity, or even thousands of times growth. The results of this technology will bring huge economic benefits. On the other hand, Specialty fiber development and its industrialization is a very active field.
The types of special fiber:
Mainly refers to the optical fiber doped with rare earth ions, such as Er3+, Nb3+, Pr3+, Yb3+ ,Tm3+ and so on to constitutes the laser active substances. This is the core material for producing fiber optical amplifier. Differently doped optical fiber amplifier is applied to the different working bands:
EDFA applied to near 1550nm (C, L-band); PDFA is mainly used in the 1310nm band; TDFA is mainly used in the S-band.
These doped fiber amplifiers and Raman fiber amplifier has brought revolutionary changes for optical fiber communication technology.
Active fiber significant role is:
To directly amplify optical signals, to extend the transmission distance;
Allocated loss compensation in optical fiber communication network and CATV network;
An indispensable keycomponents in wavelength division multiplexing (WDM) systems and optical soliton communication system.
With the Fiber amplifier, we achieve one million kilometers of optical soliton transmission without repeaters. WDM transmission distance can be substantially extended, but also makes the transmission performance optimization.
Dispersion Compensation Fiber (DCF)
Conventional G.652 fiber are at 1550nm wavelength dispersion near 17ps/nm × km. When the rate exceeds 2.5Gb / s, the increasing transmission distance will result in errors. If used in CATV systems will cause the signal distortion. The main reason is : the accumulation of positive dispersion value cause the dispersion intensifies, so that detery the transmission characteristics. In order to overcome this problem, it is necessary to adopt the negative dispersion value of the optical fiber, is about anti-dispersion fiber string access system to offset the positive dispersion value to control the size of the entire system dispersion. The reverse dispersion fiber just is the so-called dispersion compensation fiber(DCF).
The fiber grating is the use of the photosensitivity of the fiber material in the UV irradiation (usually referred to as UV “write”), to generate a periodic refractive index variation at the core of optical fiber. As we all know, the grating itself is a frequency-selective devices can be use to make many important optical passive devices and active optical devices. For example: a dispersion compensator, gain equalizer, OADM, optical filter, lightwave multiplexer, the optical module or the converter, the optical pulse compression device, the optical fiber sensor and an optical fiber laser or the like.
Multi-Coremono-Mode Fiber (MCF)
Multi-core optical fiber is a common cladding layer, containing multiple root core, and each core has its own inner cladding single mode optical fiber. The obvious advantage is the lower cost of such a fiber, about 50% lower production costs than the ordinary optical fiber. In addition, such an optical fiber can improve the integration density of a cable, and also reduce construction costs.
The above is the main achievements of the fiber-optic technology in recent years. As for the the optical cable achievements, we believe that the success and mass production, mainly in the development of optical fiber ribbon cables. This cable must have a fiber optic cable fiber access network and LAN. Fiber cable containing a total of more than one thousand to guarantee the construction of the access network.