Guide to Optical Switch

With the development of fiber optic communication technology and dense wavelength division multiplexing system, optical networking has become the trend of network communication. In optical networks, optical fiber is the fundamental medium of transmission, but switching, signaling, and processing functions are accomplished electronically. Hence, optical switches are naturally developed. Optical switch is a device used to open or close an optical circuit which enables signals in optical fibers or integrated optical circuit (IOCs) to be selectively switched from one circuit to another in telecommunication. In a network system, optical switch plays an important part in protecting the path. It is the key to all-optical switching devices and can be realized in all-optical layer routing, wavelength selection, optical cross-connect and self-healing protection function. This post intends to give a brief introduction to optical switch.

Optical Switching Technology

When it comes to optical switch, it is necessary to mention optical switching technology. As an important foundation for all-optical communication network technology, the development and application of optical switching technology will greatly influence the trend of future optical communication networks development. It is known that optical signals are multiplexed in three ways, including space division, time division and wavelength division multiplexing (WDM). Accordingly, there are three optical switching methods, space division switching, time division switching and wave division switching to complete the three multiplexed ways. Besides, there are also hybrid switching technologies used in large-scale communication network, such as time-space (TS) switching which enables broadcast operators to seamlessly switch channels within the same or different TS stream.

Types of Optical Switch

Different principles and technologies of optical switches are different in characteristic and available for different applications. And according to different specific standards, there are a number of optical switches., such as thermal optical switch, acousto-optic switch, waveguide optical switch and magneto-optic switch, etc. However, opto-mechanical optical switch and MEMS optical switch are the most widely used products in the market today.

Opto-mechanical Optical Switch

Opto-mechanical switch is the oldest type of optical switch and it is the most widely deployed switch. Due to its working principle, it is relatively slow with switching times in the 10-100ms range. Nevertheless, it can achieve excellent reliability, insertion loss, and crosstalk. Generally, opto-mechanical optical switches collimate the optical beam from each input and output fiber, then move these collimated beams around inside the device which allows distance between the input and output fiber without deleterious effects.

 MEMS Optical Switch

OptoMEMS (micro-electro-mechanical) optical switch is a micro-optical switch in free space which is made of semiconductor material. It has attracted wide attention in the world because of its versatility. MEMS optical switch is designed to have the advantage of opto-mechanical, but it is more compact and easier to expand. With the ability of combining the electrical, mechanical and optical integration as a whole, MEMS optical switch can transparently transmit different rates and different businesses services.

Application of Optical Switch

Optical switches are widely used in high speed networks where high switching speeds and large switches are required to handle the large amount of traffic. Optical switches can be used within optical cross-connects (OXCs) which contain a whole series of optical switch to forward data using switches. Furthermore, optical switches can also be utilized for switching protection. The switch can allow the signal to be rerouted to another fiber before a fiber failing to transmit the signal. And it takes an optical switch only milliseconds to detect the failure and inform network.

Conclusion

Optical switch plays a very important role in optical network, which is not only as the switching core of the key equipment in WDM network, but also as key components in optical networks. This passage provides a brief introduction to optical switch for you. FS.COM offers optical switch solutions and tutorials for your project, please visit FS.COM for more information.