An optical switch is a device that can selectively switch light signals that run through in optical fibers or integrated optical circuits from one circuit to another. That is to say, optical switches can transfer light signals between different channels in communication networks. As the growing popularity of Internet and telephone, greater quantities of data managed by communication networks also expanded. Optical switching technology provides a perfect solution to fully exploit capacity of optical systems. The main focus of this post is to introduce basics of optical switches in optical communication.
As we all know, when a light signal runs through from one computer to another in fiber optic networks, it may be required to move the signal between different fiber paths. To accomplish this, a switch is required to transfer the signal with a minimum loss. Optical switch is a technology needed. The optical switch we often see is operated by mechanical method which just moves fiber or other bulk optic components. But they can offer unprecedented high stability and unmatched low cost performance.
Optical switches are mainly deployed in establishing the light path. They feature scalability and highly reliable switching capacity. Following are the major functions that optical switches bear in optical cross networks.
- Protection. Sometimes a failure of some single point can cause the whole network breaking down. And the protection switching is to protect the transmission data, which can avoid network fault before finding the failure causes.
- Optical add/drop multiplexing. Optical switches must be equipped with the capability that can add or delete the wave channels without any electronic processing. This kind of optical switches is also called wavelength selective switches.
- Optical spectral monitoring. Optical spectral monitoring is a network management operations. In this process, operators receive a small portion of optically tapped signal for monitoring power level, wavelength accuracy and optical cross talk.
As data requirements grow, the traditional electrical switches no longer meet people’s demand. There are two major types of optical switches on the market: opto-mechanical optical switches and MEMS (Micro-electromechanical Systems) optical switches.
Opto-mechanical optical switch is an old type of switches but the most widely used one. It can produce different optical path selections out of a plurality of optical path sections that are oriented in different spatial directions. Hence opto-mechanical optical switches can be used in multi-channel optical power monitoring, optical local area networks, switching multiple laser sources or optical receivers in Ethernet networks. They are also very useful in optical fiber, components or systems testing and measurement, as well as applications in multi-point fiber sensor systems. Generally, according to the number of redirecting signals, opto-mechanical optical switches have different configurations such as 1×1, 1×2, 1×4, 1×16, etc. In simple terms, the 1×8 opto-mechanical optical switch module connects optical channels by redirecting an 1 incoming optical signal into a selected signal from 8 output fibers. This kind of optical switches can achieve excellent reliability, insertion loss, and cross talk.
MEMS optical switches use a micro-mirror to reflect a light beam. And the direction that the light beam is reflected can be changed by adjusting the angle of the mirror, which allows the input light to be connected to any out port. It is a compact optical switch which connects optical channels by redirecting incoming optical signals into the selected output fibers. And the switching state is highly stable against environmental variations of temperature and vibration due to its unique design. In some degree MEMS optical switch can be considered as a subcategory of opto-mechanical switches. But it is distinguished from opto-mechanical switches in many aspects such as the characteristics, performance and reliability. The most obvious is the opto-mechanical switch has more bulk compared to other alternatives, but the MEMS switch overcomes this. Besides, MEMS optical switches also have different configurations such as 1×8, 1×12, 1×16, etc.
As the increasing growth of high speed transmission demand for networks, optical networks have become the most cost-effective solution. Optical switches play a vital role in today’s optical network system. They can offer users significant power, space and cost savings. Now different optical switches are available on the market, so you can choose a suitable one based on your requirements.