MEMS Optical Switches - A Key Technology for the Future of Optical Communications

Introduction

MEMS optical switches are a type of optical switch that uses microelectromechanical systems (MEMS) to control the flow of light. MEMS are miniature mechanical devices that can be fabricated on a semiconductor substrate using a variety of techniques, including photolithography, etching, and deposition.

MEMS optical switches offer a number of advantages over other types of optical switches, including:

l Small size and weight: MEMS optical switches are typically much smaller and lighter than other types of optical switches, making them ideal for applications where space and weight are limited.

l Low power consumption: MEMS optical switches typically consume much less power than other types of optical switches, making them more energy efficient.

l High reliability: MEMS optical switches are typically very reliable, with failure rates of less than 1%.

Types of MEMS Optical Switches

There are two main types of MEMS optical switches:

• Rotary MEMS optical switches: Rotary MEMS optical switches use a rotating mirror to control the flow of light.
• Tilting MEMS optical switches: Tilting MEMS optical switches use a tilting mirror to control the flow of light.

Applications of MEMS Optical Switches

MEMS optical switches are used in a wide variety of applications, including:

l Telecommunications:

MEMS optical switches are used in telecommunications networks to route optical signals between different nodes.

l Data centers:

MEMS optical switches are used in data centers to connect servers and other network devices.

l Medical imaging:

MEMS optical switches are used in medical imaging devices to control the flow of light.

l Industrial automation:

MEMS optical switches are used in industrial automation systems to control the flow of light.

Future Trends

The market for MEMS optical switches is expected to grow significantly in the coming years. This is due to the increasing demand for small, lightweight, and reliable optical switches in a variety of applications.

Conclusion

MEMS optical switches are a versatile and reliable technology that is finding increasing use in a wide range of applications. As the demand for small, lightweight, and reliable optical switches continues to grow, MEMS optical switches are well positioned to continue to play a leading role in this market.

What Is Transponder and Muxponder?

 Data centers and service providers face the increasing demands for data security, low latency, higher speeds and longer distances in networks. Transponders and muxponders are both key elements that receive and send the signals over the fiber in an optical transport network.

What Is Transponder?
Transponders are used to enable point-to-point connections over long distances when the client rate matches the optical wavelength. A transponder is the element that sends and receives the optical signal from a fiber in optical fiber communications. A transponder is typically characterized by its data rate and the maximum distance the signal can travel. Transponders are used to enable point-to-point connections over long distances when the client rate matches the optical wavelength. In cases where the client rates are lower than the optical wavelength, a muxponder is used to multiplex multiple sub-rate clients onto the line interface.

What Is Muxponder?
In cases where the client rates are lower than the optical wavelength, a muxponder is used to multiplex multiple sub-rate clients onto the line interface. Muxponder is used in WDM or ROADM equipment, which needs to meet the needs of any service, port Muxponder or function card on the basis of reducing power consumption and cost. Muxponder also has the capability to combine multiple services into a single wavelength by multiplexing several channels to a higher order signal. 

200G Muxponer supports 100G or 200G OEO card. Its main function is to convert the service signals of 1*100G-QSFP28 into 1*100G-DCO coherent transceiver or 2*100G-QSFP28 to 1*200G-DCO coherent transceiver for coherent optical transmission. The line side adopts coherent optical modulation mode, and other technologies. It supports 100GE to 100G DWDM signal (100G CFP2 DCO) conversion and 2*100GE to 200G DWDM signal (200G CFP2 DCO) conversion and realize maximum transmission without repeater of 800 km, support C-band 96 channels (50GHz).

When to Use Transponders and Muxponders?
Transponders and muxponders can automatically receive, amplify and re-transmit signals on new wavelengths without any changes to the data carried over the signal at all, which can not be achieved by only adopting transceivers. However, a solution based on active transponders or muxponders is preferable when transceivers and switches are not fully compatible or when transceivers alone could not meet the real needs. 

1.When the networks need to be encrypted, transponders and muxponders can help to protect sensitive data and meet regulatory requirements with encryption.

2.When data needs to be transmitted over a long distance but the transceiver does not support long–distance WDM, an OEO-based solution with transponders and muxponders can extend the distance of WDM network and add FEC to the signal.

3.When an Internet service provider need to hand off a gray signal to end users, transponders and muxponders can help to control and restrict the bandwidth.

4.When the data needs to be transmitter at higher speeds than supported by transceivers in WDM networks, transponders and muxponders are another way to support faster speeds regardless of the transceiver form factor. 

What is Optical Circulator in Optical Communication?

Optical circulator is a multi-port optical device with nonreciprocal property. It is based on the nonreciprocal polarization of an optical signal by Faraday effect. When an optical signal is input from any port, it can be output from the next port sequentially with very low loss, and the loss from this port to all other ports is very large, so these ports are not communicating with each other.

That means that optical circulator is a three- or four-port optical device designed such that light entering any port exits from the next. If light enters port 1 it is emitted from port 2, but if some of the emitted light is reflected back to the circulator, it does not come out of port 1 but instead exits from port 3. This is analogous to the operation of an electronic circulator.

 

Fiber-optic circulators are used to separate optical signals that travel in opposite directions in an optical fiber, for example to achieve bi-directional transmission over a single fiber. Because of their high isolation of the input and reflected optical powers and their low insertion loss, optical circulators are widely used in advanced communication systems and fiber-optic sensor applications.

 

Optical circulators are non-reciprocal optics, which means that changes in the properties of light passing through the device are not reversed when the light passes through in the opposite direction. This can only happen when the symmetry of the system is broken, for example by an external magnetic field. A Faraday rotator is another example of a non-reciprocal optical device, and indeed it is possible to construct an optical circulator based on a Faraday rotator.

 

Structure Principle
It consists of a Faraday rotator and two polarizing prisms on both sides. When polarized light passes through a Faraday rotator, its polarization plane can rotate 45°under the action of an external magnetic field. As long as the optical axes of the two polarizing prisms are set at an appropriate angle to each other, the insertion loss of the inter-connected optical paths can be very low and the isolation of the disconnected optical path is very large.

 

The optical circulator can also be formed by utilizing the characteristics of the single-mode fiber will produce the Faraday rotation effect under the action of an external magnetic field. The insertion loss and isolation of the polarization-independent optical circulator are independent of the polarization state of the incident light.

 

Technical Parameters
The technical parameters of optical circulator include insertion loss, isolation, crosstalk, polarization dependent loss(PDL), polarization mode dispersion(PDM) and return loss, etc. The definitions of insertion loss, isolation, polarization dependent loss and polarization mode dispersion of optical circulators are basically the same as those of optical isolators, except that for an optical circulator, it refers to a specific index between two adjacent ports.