An optical switch is a device with one or more selectable transmission windows, which can perform mutual conversion or logical operation on optical signals in optical transmission lines or integrated optical circuits. The basic form of the optical switch is 2×2, that is, there are two optical fibers at the input end and the output end, and two connection states can be completed, parallel connection and cross connection. Larger space-splitting optical switching units can be composed of basic 2×2 optical switches and corresponding 1×2 optical switches cascaded and combined.
Optical switches play a very important role in optical networks. In Wavelength Division Multiplexing (WDM) transmission systems, optical switches can be used for wavelength adaptation, regeneration and clock extraction. In Optical Time Division Multiplexing (OTDM) system, an optical switch can be used for demultiplexing. In an all-optical switching system, an optical switch is a key device for an Optical Cross-connect (OXC) and an important device for wavelength conversion. According to the number of input and output ports of the optical switch, it can be divided into 1×1, 1×2, 1×N, 2×2, 2×N, M×N, etc. They have different uses in different occasions.
1×1 optical switch has the function of making the optical path on and off, and is usually used to block the light transmission in the optical path.
1×2 optical switch has a protection switching function and is usually used for network fault recovery. When the fiber breaks or other transmission failures occur, the optical switch is used to realize the detour route of the signal, and switch from the main route to the backup route.
2×2 optical switch is the most commonly used one in the optical switch series, widely used in FDDI, optical node bypass, loop test sensing system, etc., It also can be used in combination with other types of optical switches to make the switching system better and more flexible.
Network Monitoring When it is necessary to monitor the network, it just needs to connect the multi-fiber optical switch to the network monitoring instrument (such as OTDR) at the remote monitoring point. When the optical path needs to be monitored, use the optical switch to switch each optical fiber in a cycle. Every fiber will be tested by the light source to realize online monitoring. The optical switch mainly plays the role of testing in the optical cable monitoring system. Using a 1×N optical switch can connect multiple fibers.
Optical Device Testing Connect multiple optical devices to be tested through optical fibers and 1×N optical switches, the devices can be tested by monitoring the signal of each channel of the optical switch.
Build the Switching Core of OXC OXC is mainly used in the backbone network to aggregate and switch services of different subnets. Therefore, it is necessary to switch the services of different ports. At the same time, the use of optical switches enables OXC to dynamically configure and switch services and support protection switching functions, and supports wavelength routing configuration and dynamic routing at the optical layer. Because OXC is mainly used in high-speed and large-capacity dense wavelength division multiplexing optical backbone network, it is required that the optical switch has the characteristics of transparency, high speed, large capacity and multi-granularity switching.
Comments