Key devices of large-capacity data networks in the future-Optical Switch continued

New Optical Switch Technology

Now we have an optical switch based on thermal, liquid crystal, acoustics, and Micro-electromechanical MEM: Micro-o-Mechanical.

The thermo-Optical Switch uses an aggregation waveguide with heat regulating. The swap is controlled by thin film heating elements published in the polymer stack. When the current passes through the heater, it changes the heat distribution in the waveguide branch area, thus changing the refractive index, so that the optical coupling can be guided from the source waveguide to the target branch waveguide. This optical switch is very small in size and can achieve microsecond-level switching speed. Its disadvantage lies in its high intervention loss, severe crosstalk, low extinction rate, large power consumption, and a sound radiator.

Liquid Crystal Optical Switch Package contains liquid wafer polarization beam splitter PBS) or a first-come inverter. The liquid chip is used to rotate the Polarization Angle of the incident light. When there is no voltage on the electrode, the Polarization Angle of the light passing through the liquid wafer is 90 degrees. When the voltage is applied to the electrode of the liquid wafer, the incident light bundle will maintain its polarization state. PBS or beam inverters act as routers and direct signals to the destination port. Matrix switches that are sensitive to polarization or not sensitive can exploit this technology.

When an oriented liquid crystal is used, the switching speed of the switch is about 100 ms. When a electro-mechanical liquid crystal is used, the switching speed is 10 microseconds. Using Liquid Crystal Technology, You can construct a multi-path switch. However, its disadvantage is that it has a large loss, a large amount of thermal drift, severe crosstalk, and expensive driving circuit.

The third optical switch is based on the sound and light technology. In such a switch, by adding transverse sound waves to an optical medium such as a TeO2 crystal, light can be accurately directed from one fiber to another.

Sound and light switches can achieve microsecond-level switching speed. Using this technology, you can easily build vswitches with fewer ports. However, it is not suitable for matrix switches because complex systems need to change the frequency to control switches. In addition, the table consumption of such switches varies greatly with the wavelength, and the driving circuit is also expensive.

Another interesting switch uses MEM technology to adjust the beam in idle space. A variety of MEM switches have been developed that use different types of special low-light level devices activated by miniaturized mechanical systems.

The worry of MEM switches is that they are small in size and highly integrated, and can be produced on a large scale like an integrated circuit. However, further efforts need to be made in the production process to make MEM a viable and profitable alternative technology.

Optical switches in a photonic Network

In addition to traditional applications, optical switches will play an increasingly important role in the emerging multi-path, reconfigurable photonic networks. In order to make all-optical synchronization a reality, technologies such as DWDM, optical plug-in Multiplexing (OADM) and the first cross-connection (OXC) must be implemented.

So far, DWDM has become the main application of all-optical communication technology in long distance and man communication. Introducing OADM and OXC network elements in a user's ever-increasing network environment will help to flexibly use and allocate wavelengths. These new network elements can help operators reconfigure network traffic on the photon layer to achieve the best data transmission and quickly recover when the link fails. The all-optical network will eventually discard the slow and expensive photoelectric converter, so that the future network can run more quickly and economically. Both OADM and OXC require larger optical switching capacity.

By using an optical switch, OADM can select and unload a wavelength from a WDM signal on a node in the network, and then add a new signal to the original wavelength to continue transmission to the next node. This feature greatly enhances load management capabilities in all-optical networks. In a simple OADM design, a 2*2 optical switch and a DWDM multiplexing/demultiplexing filter can be loaded into a module to achieve selective wavelength insertion. In this kind of OADM, some new functions can also be displayed by adding components such as a variable attenuation and a photon detector.

In a DWDM network, OXC can provide a dynamic exchange connection between the input and output of M * N optical fiber. In this way, the optical crossover switch can provide one-to-multiple connections without blocking in matrix configuration. OXC can improve network viability, reduce network management costs, and re-configure signal routing on the photon layer, So that you no longer need to resend expensive digital switches. OXC operates on Guangcheng, so that it can accommodate future T-holding data based on its wavelength, bit rate and Protocol transparency.

The future of Optical Switches

In addition to the various optical switches discussed above, OADM and OXC applications provide higher speed, performance, and reliability requirements, new and improved switch technologies are emerging. Optical fiber-based all-optical switching devices with non-strong characteristics are emerging technologies. One example is the use of Nonlinear oriented coupler as optical switch. The coupling device consists of two needle cores very close to each other. When the phase of the polar material core is first configured, the core is separated, resulting in a switching effect. Because the switch is completed in the optical fiber, the switch has a high switching speed and low loss, and can achieve multi-level cascade in the matrix configuration, therefore, we hope to use it in future optical networks.

Due to the continuous expansion of optical network capacity, and the failure to adapt to the requirements of the gibit rate, the development of high-speed and high-performance switches has become an inevitable trend. When there is a more effective signal management method, all-optical communication will eventually become a reality. In the future, optical switches will play a key role in large-capacity optical networks.

The content of the optical switch is not limited to the above content. I hope you can master it more.