Patent Application
20200142182
This invention relates to MEMS optical switches. More specifically, this invention relates to MEMS optical switches with micro optical filters.
The telecommunications and connectivity technologies have been rapidly developing new methods in order to meet customers' demand for faster data speed and higher throughput of data traffic. Technologies such as mobile data, video-on-demand, social media and so on pose new challenges to data traffic management and drive innovations that address problems in high speed data processing.
In data intensive applications, such as those found in datacenters, data traffic is increasingly being processed in optical medium instead of conventional electrical medium. That is because optical communications have many advantages over traditional communication methods in terms of having high data throughput, low costs, small formfactors etc. Optical based data traffic has increasingly becoming a critical form of data traffic in those applications.
One critical process in managing high data traffic is data switching, i.e. distributing received incoming data to their destinations for use or further processing. Switches are specifically designed with regard to the underlying type of signal it processes. For optical data switching, optical switches must be used. Among the many different types of optical switches, Micro Electronics Mechanics System (“MEMS”) optical switch is a popular choice. MEMS devices are electromechanical devices with microscopic moving parts driven by very small electric currents. Conventionally, MEMS optical switches manage optical data traffic by using reflective micromirrors. In MEMS optical switches, optical signals propagate in short free space between the transmitter and the receiver, or transceivers, located on the optical paths, or propagation paths, of the optical signals. When it is determined that switching is needed for an optical signal, the MEMS optical switch is activated and places a micromirror on the optical signal's free space propagation path, optically switching the optical signal to the destination transceiver located on the switched free space path.
Conventional optical switches have many disadvantages, including: channel interferences when providing an any-to-any switching, slow switching speed; lack of wavelength selection and express channel for pass-through, switching restrictions brought by refection-only micromirrors, fixed array of transceiver that cannot be individually replaced, vulnerability in switch malfunctions when there is power outage, limited scalability, limited capability in adjusting power splitter ratio, signal monitoring and tapping, complicated design in channel arrays and costly maintenance and upgrade.
As such, there is a need for a MEMS optical switch that overcomes the disadvantages of the conventional switches.
An object of the present invention is to provide a MEMS optical switch. The switch includes plurality of optical transceivers in a 2D plane comprising an X-axis and a Y-axis with m pairs of optical transceivers lining along the Y-axis and n pairs of optical transceivers lining along the X-axis, wherein each transceiver of a pair is located on an optical path across an optical filter matrix of another transceiver of said pair; an optical filter matrix comprising m×n micro optical filter units, wherein each micro optical filter unit is located on a cross point of optical paths of an X-axis transceiver pair and Y-axis transceiver pair man optical filter matrix board on which the optical filter matrix is located; and a controller configured to provide MEMS control signals. Each micro optical filter unit of the MEMS optical switch is configured to be able to be activated by the MEMS control signals and switching optical signals transmitted through the cross point where the micro optical filter unit is located.
According to this object of the present invention, each micro optical filter unit further includes: a micro optical filter assembly configured to be movable within a unit frame of said micro optical filter assembly.
Further according to this object of the present invention, the micro optical filter assembly further includes: a rotation shaft; and at least one micro optical filter attached to the rotation shaft. The rotational shaft is configured to be rotatable to place the at least one optical filter to one of an optical path space and an inactive space.
Further according to this object of the present invention, the micro optical filter assembly further includes: at least one tail rod; and a plurality of magnetic tabs attached to the at least one tail rods, wherein at least one of the magnetic tabs is of a magnetic north and at least one of the magnetic tabs is of a magnetic south. An electro-magnetic field may be actuated in accordance with the MEMS control signal, said electro-magnetic field interacts with the plurality of magnetic tabs and drives the rotation shaft to place one of the at least one micro optical filter to the optical path space.
Further according to this object of the present invention, the MEMS optical switch may further include one micro optical filter and two magnetic tabs. When the electro-magnetic field is not actuated, the micro optical filter is located in the inactive space. Alternatively, the MEMS optical switch may include two micro optical filters, and three magnetic tabs, wherein when the electro-magnetic field is not actuated, the two micro optical filters are located in the inactive space. Further alternatively, the MEMS optical switch may include three micro optical filters, and four magnetic tabs, wherein when the electro-magnetic field is not actuated, the three micro optical filters are located in the inactive space. Still further alternatively, the MEMS optical switch may include a stepper motor attached to the rotation shaft, wherein the stepper motor is configured to drive the rotation shaft to place one of the at least one micro optical filter to the optical path space.
Further according to this object of the present invention, the at least one micro optical filter may be a micromirror, a coated micro lens, wherein the coated micro lens reflects a first plurality of wavelengths and passes a second plurality of wavelengths, or may include two micro lenses in contact with each other on a tilted coated surface with a tilting angle θ, wherein the micro optical filter reflects a first plurality of wavelength to an angle adjusted by the tilting angle 9 and passes a second plurality of wavelengths.
According to another object of the present invention, a 2D MEMS optical switch is provided herein, which includes: a plurality of free space optical paths in a 2D plane including an X-axis and a Y-axis with m horizontal optical paths and n vertical optical paths; l pairs of optical transceivers located on the m horizontal paths, wherein l<m, and k pairs of optical transceivers located on the n horizontal paths, wherein k<n, wherein each transceiver is located on an optical path across an optical filter matrix of another transceiver of said pair, and wherein at least one pair of the l pairs of transceivers and the k pairs of vertical optical is configured to be moveable and transmits optical signals on at least two optical paths; the optical filter matrix including m×n micro optical filter units, wherein each micro optical filter unit is located on a cross point of optical paths of an X-axis transceiver pair and Y-axis transceiver pair; an optical filter matrix board on which the optical filter matrix is located; and a controller configured to provide MEMS control signals, wherein each micro optical filter unit is configured to be able to be activated by the MEMS control signals and switching optical signals transmitted through the cross point where the micro optical filter unit is located.
Further according to the other object of the present invention, each micro optical filter unit further includes a micro optical filter assembly configured to be movable within a unit frame of said micro optical filter assembly.
Further according to the other object of the present invention, the micro optical filter assembly includes: a rotation shaft; at least one micro optical filter attached to the rotation shaft, wherein the rotational shaft is configured to be rotatable to place the at least one optical filter to one of an optical path space and an inactive space.
Further according to the other object of the present invention, the micro optical filter assembly may further includes: at least one tail rod; and a plurality of magnetic tabs attached to the at least one tail rods, wherein at least one of the magnetic tabs is of a magnetic north and at least one of the magnetic tabs is of a magnetic south, wherein an electro-magnetic field may be actuated in accordance with the MEMS control signal, said electro-magnetic field interacts with the plurality of magnetic tabs and drives the rotation shaft to place one of the at least one micro optical filter to the optical path space.
Further according to the other object of the present invention, the micro optical filter assembly may further include a stepper motor attached to the rotation shaft, wherein the stepper motor is configured to drive the rotation shaft to place one of the at least one micro optical filter to the optical path space.
Further according to the other object of the present invention, the at least one micro optical filter includes two micro lenses in contact with each other on a tilted coated surface with a tilting angle θ, wherein the micro optical filter reflects a first plurality of wavelength to an angle adjusted by the tilting angle θ and passes a second plurality of wavelengths.
Yet another object of the present invention is to provide a 3D MEMS optical switch, including a plurality ff optical transceiver layers. Each layer including a plurality of optical transceivers in a 2D plane comprising an X-axis and a Y-axis with m pairs of optical transceivers lining along the Y-axis and n pairs of optical transceivers lining along the X-axis, wherein each transceiver of a pair is located on an optical path across an optical filter matrix of another transceiver of said pair; the optical filter matrix comprising m×n micro optical filter units, wherein each micro optical filter unit is located on a cross point of optical paths of an X-axis transceiver pair and Y-axis transceiver pair; an optical filter matrix board on which the optical filter matrix is located; and a controller configured to provide MEMS control signals; wherein each micro optical filter unit is configured to be able to be activated by the MEMS control signals and switching optical signals transmitted through the cross point where the micro optical filter unit is located.
Further according to the yet another object of the present invention, an optical filter unit is further configured to be able to switch optical signals transmitted from a first transceiver located in a first layer of the MEMS optical switch to a second transceiver located in a second layer of the MEMS optical switch.
As such, the present invention provides a main switching mechanism using electro-magnetic pole activation. It provides a non-intrusive any-to-any matrix based optical switch without channel interference.
Another advantage of the present invention is that it provides a fast optical switch with switching speed in the range of micro- to mini-seconds.
Yet another advantage of the present invention is the switching mechanism covers optical channel path change, wavelength selection and express channel for pass-through channels.
Yet another advantage of the present invention is to provide an optical switch using lens interface, wherein each lens interface may provide a multi-way channel cross-connect.
Yet another advantage of the present invention is to provide optical transmitters and receivers that can be individually replaced.
Yet another advantage of the present invention is that the optical switch can be extended to 3D and multi-directions using different layers of optical coatings on the lens.
Yet another advantage of the present invention is to provide an optical switch that can provide an adjustable power splitter ratio, signal monitoring and tapping.
Yet another advantage of the present invention is to provide an optical switch, wherein each of the channels can be replaced or upgraded separately.
The above-mentioned advantages and other features of the present invention will become more apparent to and the invention will be better understood by people skilled in the art with reference to the following description of the preferred embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
One or more embodiments are illustrated by way of example, and not by limitation. In the figures of the accompanying drawings, elements having the same reference numeral designations represent like elements throughout. The drawings are not to scale, unless otherwise noted. It is to be understood that all terminologies and phraseology used herein are for the purpose of illustration and should not be understood as limiting. The phrases such as “including”, “comprising”, “having” and other variations thereof are meant to encompass the items as described, their equivalents without excluding any additional items thereof.
According to a preferred embodiment of the present invention, all of the optical transceivers 110 are of the same type. There are a total number of 2m+2n optical transceivers 110 lining up the rectangular peripheral of the optical filter matrix 120. Parallel to the Y-axis, i.e. the vertical axis illustrated in
Similarly, parallel to the X-axis, i.e. the vertical axis illustrated in
As such, people skilled in the art will appreciate that the MEMS switch 100 has a total of m horizontal free-space optical paths and n vertical free-space optical paths crossing each other at m×n cross points. According to an embodiment of the present invention, at each of the cross point, a micro optical filter unit 200 is placed therein to switch any optical signals transmitted freely on one optical path. The micro optical filter units will be described in more detail later.
As illustrated in
According to the preferred embodiment of the present invention, all optical signals travels to one side of the matrix board 130, whereas no optical signal travels to the other side of the matrix board 130. As such, the space where the optical signals are transmitted on the optical paths between the transceivers is denoted as the optical path space, and the space where no optical signals will be transmitted is denoted as the inactive space. For convenience, the optical path space may also be referred to as the upper side of matrix board 130 and the inactive space may be referred to as the lower side of the matrix board 130.
Depending on the space each micro optical filter unit 200 of matrix 120 is in, the micro optical filter 200 may either in an active state and an inactivate state. When all of the micro filters in a micro optical unit 200 stay in the inactive space, the micro optical unit 200 is said to be in an inactive state. Whereas when at least one of the micro filters in a micro optical unit 200 is in the optical path space, the micro optical unit 200 is said to be in an active state. Therefore, when a micro optical unit 200 is inactive, all of its micro filters stay below matrix board 130; whereas when a micro optical unit is active, at least one of its micro filters is above the matrix board 130 in the optical path space. During the process of activation, at least one of the micro optical filters will be moved from the inactive space and placed at the corresponding cross point in the optical path space where the micro optical unit 200 is located. Detailed description of the structure and operation of the matrix 120, matrix board 130 and the micro optical filter units 200 will be described in more detail later.
Controller 140 provides control signals for the MEMS switch 100. The control signals may be generated by the controller 140 or received from other computing units. Controller 140 provides control signals to all components of MEMS switch 100, including all transceivers 110, the micro optical filter matrix 120 comprising micro optical filter units 200, and the matrix board 130. The controller signals are derived by algorithm taking into account information such as the need and requirement of the system, network traffic, the type of the optical filters, pre-conditions etc. and provided appropriate to all relevant components for coordinating the desired optical data switching. It will be appreciated by people skilled in the art that controller 140 is schematically rendered in
According to another embodiment of the present invention not shown in
Assembly 300 is attached via the filter bearings 50 to the unit frame 240 and can be tilted, rotated and other moved in order to switch the optical signals on the unit frame 240. The frame bearings 250 are immovably attached to the matrix board 130. As such the unit frame 240 in the same X-Y plane as the matrix board 130. The filter bearings 50 are bearing points by which assembly 300 moves Control and other electrical signals for assembly 300 may also wire through the filter bearings 50.
It is understood by people skilled in the art that assembly 300 is schematically and conceptually rendered in
A plurality of embodiments of assembly 300 is now described in connection with
Referring to
Towards one end of the rotation shaft 20, an elongated tail rod 70 is attached at its midpoint thereto, perpendicularly both to the rotation shaft 20 and the micro optical filter 10. Balanced on each end of tail rod 70 are two magnetic tabs. The first magnetic tab 30-a is of one of a magnetic dipole and the second magnetic tab 30-b is of the other dipole. As illustrated in
At each end of rotation shaft 20, filter bearings 50 mechanically connect to the micro optical filter unit 200 as illustrated in
As described above, when the assembly 300-A is not active, micro optical filter assembly 300-A stays in the inactive position as illustrated in
When the assembly 300-A needs to be activated, controller 140 will send control signal to actuate a magnetic field around the micro optical filter assembly 300-A according to known art. The magnetic field will interact the magnetic tabs 30-a and 30-b on tail rod 70 in such a way that it will push and/or pull the tabs and move them out of their current inactive locations. As a result, tail rod 70 starts to exert torsional forces at rotation shaft 20. Rotation shaft 20 will then start to rotate between the bearing points 50, which will turn the micro optical filter 10 out of the inactive space up towards the optical path space. The magnetic field is configured to stop the rotation and stabilize the assembly 300-A when the micro optical filter 10 is in the activated position where optical switching may be conducted. When the micro optical filter assembly 300-A needs to be deactivated, the controller 140 may simply send signals to withdraw the magnetic field around the assembly 300-A, which will automatically return to the inactive state due to gravity pull.
The assembly 300-B's inactive state and activate states are as follows. When the assembly 300-B is inactive, it rests in a position where the first micro optical filter 10-a and the second micro optical filter 10-b are balanced on each side of the full tail rod 70a, parallel to the plane of the matrix board 130, which is a stable position of the assembly 300-B without an actuated magnetic field, or where there is no power or a power outage.
When the micro optical filter assembly 300-B is active, an actuated micro magnetic field around assembly 300-B will exert mechanical forces on the magnetic tabs 30-a, 30-b and 30-c, which will cause the rotation shaft 20 to turn, resulting in either the micro optical filter 10-a or 10-b being placed in the optical path space to switch the optical signals. Therefore, assembly 300-B has two active states. The magnetic field is configured to allow either one of the 10-a or 10-b to be placed on the optical path space for optical switching according to known art. The advantages 300-B is to provide additional switching options.
For example, micro optical filters 10-a and 10-b may be micromirrors configured with different incident and reflection angles. One of them may reflect an incident signal to 90 degrees, and the other to −90 degrees. As such, by activating either 10-a or 10-b, the assembly 300-B may switch the incident optical signal to either one of the transceiver pair on the same switched optical path, thus simplifying the implementation of an any-to-any switching capacity.
Regarding the optical filters, according to one embodiment, the micro optical filters 10-a, 10-b and 10-c are of same shape, dimension and weight, but with different optical characteristic. According to another embodiment, the middle micro optical filter, namely 10-b in
Regarding the magnetic tabs 30-a, 30-b, 30-c and 30-d, according to a preferred embodiment, they are all of the same shape, dimension and weight. The polarization of the tabs can be any combination that do not impede the rotation of the rotation shaft 20 when the magnetic field is actuated. As such the assembly 300-C has 3 activated state with either 10-a, 10-b or 10-c placed on the optical paths, which provides further switching choices for the MEMS switch 100.
The micro optical filters 10 throughout embodiments 300-A to 300-D can be any type of optical filters. They can be micromirrors, including total reflection micromirrors that reflect the entire spectrum of the optical signal they receive, selective pass micromirrors that reflect most spectrums but not certain wavelengths, or narrow band pass micro mirrors that only reflect selective bandwidth of the optical signal. In addition, the micro optical filters can be lenses that refract or allow to pass the whole or certain optical signals depending on the wavelength thereof The micro optical filters will be descried in more detail below.
In
In
The embodiments of micro optical filters 10-iii illustrated in
The MEMS switch 100 illustrated in
It is appreciated by people of ordinary skill of the art that the present invention provides a non-intrusive any-to-any matrix based optical switch without channel interference.
For example, with regard to the 2D optical switch, any optical signals from an X-axis transceiver can be switched to any of the Y-axis transceivers and vice versa, wherein the optical paths of the signals do not interest or cross each other hence eliminating channel interference.
Another advantage of the present invention is that it provides an optical switch with fast switching speed in the range of micro- to mini-seconds due to the usage of the Electro-magnetic actuation or the stepper motors. In the meantime, the switching mechanism covers optical channel path change, wavelength selection and express channel for pass-through channels.
Yet another advantage of the present invention is to provide an optical switch using lens interface, wherein each lens interface may provide a multi-way channel cross-connect as illustrated in
Yet another advantage of the present invention is to provide optical transmitters and receivers that can be individually replaced.
Yet another advantage of the present invention is that the optical switch can be extended to 3D and multi-directions using different layers of optical coatings on the lens.
Yet another advantage of the present invention is to provide an optical switch that can provide an adjustable power splitter ratio, signal monitoring and tapping.
Yet another advantage of the present invention is to provide a simplified channel array replaceable for any baud rate signal.
Yet another advantage of the present invention is to provide an optical switch, wherein each of the channels can be replaced or upgraded separately.
It is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided herein would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. That is, it should be understood that the application is capable of modification and variation. As such, the following claims are hereby incorporated into the Detailed Description of the Preferred Embodiments, with each claim standing on its own as a separately claimed subject matter.
