The optical switch is an optical device with 1 or N channels to choose from, which can switch the optical signal from one channel to another, thereby realizing optical path switch. According to different principles, there are many types of optical switches. At present, mechanical optical switch is widely used, which mainly rely on moving optical fibers or optical components to switch optical paths.

Aided by the mechanical device, mechanical optical switch is able to move optical fibers or other components to direct the light from the input port to the certain output port. According to the different driven components, there are three main application principles:

1. Switch fiber:

2. Switch optical prism:

3. Switch reflector:

Although the mechanical optical switch is widely used because of the advantage of low cost, its large size and difficulty in large-scale integration limit its future application in optical communication. With the continuous progress of technology, MEMS (Micro-Electro-Mechanical) optical switch has become the development direction of optical switches for large-capacity optical network switching. It is a new type of mechanical optical switch that combines MEMS and traditional optical technology, with the advantage of low loss, low crosstalk and high extinction ratio. At the meanwhile, it also has the characteristics of small size, low polarization loss and fast switching speed.

The application principle of MEMS optical switch is mainly based on micro lens and micro reflector.

Micro-reflector-based MEMS optical switch1

Micro-reflector-based MEMS optical switch2

Micro-lens-based MEMS optical switch3

Micro lens array (Can be rotated in multiple directions)

Usually there are several type of optical switch as 1×1, 1×2, 2×2 and M×N. The following will explain their applications.

1×1 Optical Switch

The connection and disconnection of the optical path can be realized by simple switch.

1×2 Optical Switch

To switch the optical path to the standby routing when the primary one fails.

2×2 Optical Switch

2x2 optical switch is the most widely used. It is usually applied in OADM node equipment for wavelength division multiplexing in backbone networks and metropolitan area networks. It can realize dynamic configuration of services to enhance the flexibility of nodes in the entire network system, and switch the problematic service under the node to the standby routing, so as to improve the stability of the entire network.

M×N Optical Switch

It is often used in network monitoring, optical device testing and building the switching core of optical cross-connect equipment.