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Application of WDM technology in communication network capacity expansion


1、 What is optical wavelength division multiplexing technology?

WDM (wavelength division multiplexing) technology is a technology that can transmit multi wavelength optical signals on an optical fiber at the same time. The optical signals of different wavelengths are combined (multiplexed) at the transmitting end and coupled to the same optical fiber on the optical cable line for transmission. At the receiving end, the optical signals of combined wavelengths are separated (demultiplexed) and further processed to recover the original signals and send them to different terminals. Therefore, this technology is called optical wavelength division multiplexing (WDM).

About 200 nm low loss region is available in 1310 nm wavelength band and 1550 nm wavelength band, which is equivalent to the frequency band width of 30000 GHz. However, in the current actual optical fiber communication system, due to the limitation of optical fiber dispersion and modulation rate, the communication rate of single-channel TDM system is limited to 10Gbit / s or less, so most bandwidth resources of single-mode optical fiber need to be developed.

2、 WDM and DWDM

WDM system is mainly composed of the following five parts: optical transmitter, optical relay amplification, optical receiver, optical monitoring channel and network management system. The application of WDM system is of great significance to increase communication capacity and the construction of information network, but there are still some technical problems. For example, the wavelength and stability of the laser are highly required; The nonlinearity of optical fiber limits the output power of optical amplifier“ "Four wave mixing" effect will cause crosstalk between channels; The dispersion effect of optical fiber limits the improvement of channel rate; How to monitor the line optical amplifier.

Among them, the wavelength division multiplexing with small channel spacing in the same low loss window of the optical fiber is called dense wavelength division multiplexing (DWDM).

Sharetop DWDM (dense wavelength division multiplexing) equipment system has a variety of networking modes, which can form point-to-point, chain, ring, single fiber bidirectional, one-to-many and other network connections. The number of service channels can reach 48 waves, the maximum transmission rate of single wavelength is 40Gbit / s, and the maximum transmission capacity of the system can reach 1920gbit. It has the characteristics of high speed and large capacity. You can gradually increase the wavelength to expand the capacity according to the actual business volume, which is very economical and flexible. DWDM (dense wavelength division multiplexing) system technology can make full use of the huge bandwidth resources of optical fiber and increase the transmission capacity of an optical fiber by dozens or even hundreds of times compared with single wavelength transmission. It is the best solution to deal with the shortage of optical cable resources at present.



 


XYT-1600 Series wavelength division transmission platform


In addition to the advantages of large capacity and flexible networking,Sharetop DWDM transmission system also has 1 + 1 optical protection function and 1 + 1 power thermal redundancy backup to provide safe and stable transmission lines. At the same time, it also has flexible network management configuration, adopts SNMP based graphical interface, and can support in band and out of band management. The network management system adopts embedded operating system, with real-time monitoring function, flexible and diverse management methods, friendly man-machine interface and convenient and reliable use experience.