Graph core technology of All Optical Networks: optical switching technology (1)

In modern communication networks, dense wavelength division multiplexing (DWDM) optical transmission networks make full use of the huge bandwidth resources of optical fiber to meet the explosive growth needs of various communication services. However, the transmission and exchange of high-quality data services still adopt multi-layer network architecture solutions such as IP over ATM and IP over SDH, which not only have a huge overhead, but must also undergo photoelectric conversion on the transit node, the underlying DWDM Bandwidth Resources and powerful wavelength routing capabilities cannot be fully utilized. In order to overcome the electronic bottleneck in optical networks, a highly survivability all-optical network has become the future development goal of broadband communication networks. As an important supporting technology in the all-optical network system, optical switching technology plays an important role in the all-optical communication system, it can be said that the development of optical exchange technology also determines the development of all optical communication to some extent.

I. Definition and features of optical switching　

The optical switching technology means that the input optical signals are directly exchanged to different output ends without any optical/electrical conversion. The optical switching system consists of the input interface, optical switching matrix, output interface, and control unit, as shown in 1.

Figure 1

Currently, Optical Logic Devices have simple functions and cannot complete some complex logic processing functions. Therefore, the existing optical switching control units in the world must be completed by electrical signals, the so-called electronic control optical switching. Photoelectric conversion is performed at the input end of the control unit, while electro-optic conversion is required at the output end. With the development of optical device technology, the ultimate development trend of optical switching technology will be optical switching.

As the communication network develops towards an all-optical platform, network optimization, routing, protection, and self-healing functions become more and more important in the optical communication field. The optical switching technology can overcome the capacity bottleneck of electronic switching, achieve high-speed network rate and Protocol transparency, improve the flexibility and survivability of network reconstruction, and greatly save the cost of network construction and network upgrade.