MEMS Optical Switch with Micro Optical Filters

A MEMS optical switch with micro optical filters using is disclosed. The optical switch provides any-to-any non-intrusive multi-layer optical switching using micro optical filters such as micromirrors and micro-lenses activated and deactivated using MEMS technology. 3-D optical switches using the same switching design can also be constructed by combining multiple MEMS optical switches together.

TECHNICAL FIELD

This invention relates to MEMS optical switches. More specifically, this invention relates to MEMS optical switches with micro optical filters.

BACKGROUND OF THE INVENTION

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.

SUMMARY OF THE INVENTION

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 angle9and 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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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.

FIG. 1is a top view of a schematic diagram of the MEMS optical switch with micro optical filters according to a preferred embodiment of the present invention. Referring toFIG. 1, the MEMS optical switch with micro optical filters100(hereinafter “the MEMS switch100” or “the switch100”) includes a plurality of optical transceivers110, including all items starting with the numerical “110” inFIG. 1, which will be described in further detail below. The plurality of optical transceivers110are lined up to in surrounding a micro optical filter matrix120. The micro optical filter matrix120comprises a matrix of micro optical filter units200, including all items starting with the numerical “200” inFIG. 1,, which will be described in further detail below. Micro optical filter matrix120located on micro optical filter matrix board130, which provides a physical framework in support of the operation of the micro optical filter matrix120. The MEMS switch100further includes controller140, which provides control signals to the system. The top view of the MEMS switch100is in a 2D plane consisting an X-axis and a Y-axis as illustrated inFIG. 1. A Z-axis of the 3-dimentional (hereinafter “3D”) space the MEMS switch100is located is not shown herein. People skilled in the art will appreciate that the Z-axis is perpendicular to the 2D plane. The various components of the MEMS switch100will now be described in further detail below.

According to a preferred embodiment of the present invention, all of the optical transceivers110are of the same type. There are a total number of 2m+2n optical transceivers110lining up the rectangular peripheral of the optical filter matrix120. Parallel to the Y-axis, i.e. the vertical axis illustrated inFIG. 1, there are m pairs of transceivers, i.e.110Y1,110Y2, . . . ,110Ymlocated on the left side of the micro optical filter matrix120and110Y1′,110Y2′,110Ym′located on the right side of the micro optical filter matrix120(hereinafter collectively “Y-transceivers”). The Y-transceivers on the left and right sides face each other and are placed in m pairs, wherein the paired Y-transceivers are in each other's free space optical propagation path to transmit and receive optical signals to and from each other when no optical switch is placed on the optical propagation path.

Similarly, parallel to the X-axis, i.e. the vertical axis illustrated inFIG. 1, there are n pairs of transceivers, i.e.110x1,110x2, . . . ,110xnlocated on the up side of the micro optical filter matrix120and110x1′,110x2′, . . .110xn′located on the bottom side of the micro optical filter matrix120(hereinafter collectively “X-transceivers”). The X-transceivers on the up and bottom sides face each other and are placed in n pairs, wherein the paired X-transceivers are in each other's free space optical propagation path to transmit and receive optical signals to and from each other when no optical switch is placed on the optical propagation path.

As such, people skilled in the art will appreciate that the MEMS switch100has 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 unit200is 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 inFIG. 1, the MEMS micro optical filter matrix120(hereinafter “matrix120”) is located in the center surrounded by the transceivers110. The matrix120comprises a total number of m×n micro optical filter units20000,20001. . . ,2001n,20011. . .200mn(hereinafter collectively “optical filter units200”), each located at a cross point of the free space optical paths of the transceivers110. All of the micro optical filter units200are attached to the micro optical filter matrix board130, which is on the same 2D plane of the switch100. The matrix board130provides mechanical support, operating space, as well as control signal circuitry for each of the micro optical filter units200of the matrix120.

According to the preferred embodiment of the present invention, all optical signals travels to one side of the matrix board130, whereas no optical signal travels to the other side of the matrix board130. 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 board130and the inactive space may be referred to as the lower side of the matrix board130.

Depending on the space each micro optical filter unit200of matrix120is in, the micro optical filter200may either in an active state and an inactivate state. When all of the micro filters in a micro optical unit200stay in the inactive space, the micro optical unit200is said to be in an inactive state. Whereas when at least one of the micro filters in a micro optical unit200is in the optical path space, the micro optical unit200is said to be in an active state. Therefore, when a micro optical unit200is inactive, all of its micro filters stay below matrix board130; whereas when a micro optical unit is active, at least one of its micro filters is above the matrix board130in 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 unit200is located. Detailed description of the structure and operation of the matrix120, matrix board130and the micro optical filter units200will be described in more detail later.

Controller140provides control signals for the MEMS switch100. The control signals may be generated by the controller140or received from other computing units. Controller140provides control signals to all components of MEMS switch100, including all transceivers110, the micro optical filter matrix120comprising micro optical filter units200, and the matrix board130. 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 controller140is schematically rendered inFIG. 1. In other embodiments, controller140may be placed in other locations in the MEMS switch100, or consist of several components, each located at a different location. It may either generate control signal locally or use control signal received from other computing units not shown inFIG. 1. The circuitry of the controller connecting to the rest of the components of the MEMS switch100can also have various layouts. It is understood by people skilled in the art that all these variations on the controller140are within the scope of the present invention.

According to another embodiment of the present invention not shown inFIG. 1, the MEMS switch100of a m xn micro optical filter matrix120may have less than m transceiver pairs on the Y-axis and/or less than n transceiver pairs on the X-axis. According to these embodiments, some or all of the transceivers are configured to move along their respective axes in a predetermined range. As such, a transceiver may provide optical signals to more than one optical path. For example, there may be only one transceiver pair located on the Y-axis. This single pair of transceivers may move along the sides of a matrix120comprising m xn micro optical filters units and may stop at any of the m horizontal optical paths. People skilled in the art will appreciate that the single moveable pair transceiver can accomplish almost all functions of an optical switch system comprising m pairs of Y-transceivers by originating or receiving the optical signals on the m horizontal paths in a serial manner. Alternatively, there may be more than one transceiver pairs on each axis, each covering a number of optical paths. There may be any number of transceiver pairs on each of the X- and Y-axis in the range of 1 to m on the -axis and 1 to n on the X-axis. These embodiments can be implemented using well-known or obvious prior art methods such as by including sliding tracks and respective sliding components on the movable transceivers to cover more than one optical path. Other electrical and/or mechanical designs may be provided to facilitate the moving of the transceiver, which are also within the scope of the present invention.

FIG. 2is a schematic top view of a micro optical filter unit200of the matrix120. As illustrated inFIG. 2, the micro optical filter unit200includes a unit frame240, a micro optical filter assembly300(hereinafter “assembly300”), a plurality of micro optical filter bearings50(hereinafter “filter bearings50”), and a plurality of frame bearings250.

Assembly300is attached via the filter bearings50to the unit frame240and can be tilted, rotated and other moved in order to switch the optical signals on the unit frame240. The frame bearings250are immovably attached to the matrix board130. As such the unit frame240in the same X-Y plane as the matrix board130. The filter bearings50are bearing points by which assembly300moves Control and other electrical signals for assembly300may also wire through the filter bearings50.

It is understood by people skilled in the art that assembly300is schematically and conceptually rendered inFIG. 2, in which it is represented by a shaded rectangular shape. As will be illustrated in more detail below in connection with the rest of the accompanying figures, it is noted that assembly300may have many different components and structures in the 3D space. The illustration of the 2D rectangular shape of the filter assembly300inFIG. 2is by no means intended and should never be interpreted as limiting the shape, dimension or other geometrical features of assembly300. Rather, people skilled in the art shall refer to the detailed description of the embodiments of the filter assembly300below.

A plurality of embodiments of assembly300is now described in connection withFIGS. 3A-3D.FIGS. 3A-3Dare perspective views of embodiments of the micro optical filter assembly300. InFIGS. 3A-3D, the embodiments of micro filter assembly300are further identified with added alphabetic letters, i.e.300-A,300-B,300-C and300-D, in order to distinguish the embodiments from each other.

Referring toFIG. 3A, the assembly300-A comprises a micro optical filter10, a rotation shaft20, a first magnetic tab30-aof one of the N-S magnetic dipole, a second magnetic tab30-bof the other dipole, filter bearings50, and tail rod70. The assembly300-A as illustrated inFIG. 3Ais in the inactive state, which will also the position the assembly300-A be in when there is a power outage or otherwise no power in the system due to the gravity pull. Rotation shaft20is an elongated mechanical shaft that rotates freely between the filter bearings50and is central in activating or deactivating the micro optical filter unit200. At approximately the middle part of rotation shaft20, a micro optical filter10is fixedly attached thereto. With the rotation of the rotation shaft20, micro optical filter10will then be moved up from the inactive space to the optical path space. When rotation shaft20rotates approximately 180 degrees from the inactive state, assembly300-A will be in the activated state, wherein the micro optical filter10is placed in the optical path of incoming optical signals. Rotational degrees other than 180 degrees are also possible, as long as the optical filter10is rotated to a position where optical signals can be switched.

Towards one end of the rotation shaft20, an elongated tail rod70is attached at its midpoint thereto, perpendicularly both to the rotation shaft20and the micro optical filter10. Balanced on each end of tail rod70are two magnetic tabs. The first magnetic tab30-ais of one of a magnetic dipole and the second magnetic tab30-bis of the other dipole. As illustrated inFIG. 3A, the first tab30-ais an N-pole and the second tab30-bis an S-pole. Alternatively, the first tab30-ais an S-pole and the second tab30-bis an N-pole. The tabs may be of the same dipole as well. The tabs30-aand30-bare otherwise identical in shape, size and weight etc. It will be appreciated by people skilled in the art that the inactive state of the micro optical filter assembly300-A is stable due to the balanced tabs30-aand30-band the gravity pull.

At each end of rotation shaft20, filter bearings50mechanically connect to the micro optical filter unit200as illustrated inFIG. 2. Filter bearings50are connected to the micro optical filter unit200in such a way that assembly300-A may freely rotate along rotation shaft20according to control signals.

As described above, when the assembly300-A is not active, micro optical filter assembly300-A stays in the inactive position as illustrated inFIG. 3A. Micro optical filter assembly300-A is activated by generating an electro-magnetic field that interacts with magnetic tabs30-aand30-b.More particularly, the MEMS micro optical filter switch system100includes components that generate and change micro magnetic fields around each of the assembly300-A according to known art.

When the assembly300-A needs to be activated, controller140will send control signal to actuate a magnetic field around the micro optical filter assembly300-A according to known art. The magnetic field will interact the magnetic tabs30-aand30-bon tail rod70in 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 rod70starts to exert torsional forces at rotation shaft20. Rotation shaft20will then start to rotate between the bearing points50, which will turn the micro optical filter10out of the inactive space up towards the optical path space. The magnetic field is configured to stop the rotation and stabilize the assembly300-A when the micro optical filter10is in the activated position where optical switching may be conducted. When the micro optical filter assembly300-A needs to be deactivated, the controller140may simply send signals to withdraw the magnetic field around the assembly300-A, which will automatically return to the inactive state due to gravity pull.

FIG. 3Bis another embodiment of the micro optical filter assembly300. Assembly300-B is similar to assembly300-A with a few modifications. Referring toFIG. 3B, the micro optical filter assembly300-B includes two micro optical filters10-aand10-b,both attached to the rotation shaft20at the same distance from either ends of rotation shaft20. They are 180 degrees separated from each other. The micro optical filters10-aand10-bare of the same shape, dimension and weight. However, they may have different optical filtering characteristics, the advantage of which will be described later.300-B further includes a first magnetic tab30-a,a second magnetic tab30-b,a third magnetic tab30-c,filter bearings50, a full tail rod70aand a half tail rod70b.Tabs30-aand30-bare of same size, weight and shape and balanced on the ends of full tail rod70a,similar to the embodiment of3A. An additional half tail rod70bis fixedly attached to the full tail rod70aat its midpoint, wherein at the end of which another magnetic tab30-cis attached. According to one embedment of3B,30-aand30-bare of the N pole whereas30-cis S pole. Other polarization of the tabs30-a,30-band30-cthat will interact with a magnetic field and turn the assembly300-B are also within the scope of the present invention.

The assembly300-B's inactive state and activate states are as follows. When the assembly300-B is inactive, it rests in a position where the first micro optical filter10-aand the second micro optical filter10-bare balanced on each side of the full tail rod70a,parallel to the plane of the matrix board130, which is a stable position of the assembly300-B without an actuated magnetic field, or where there is no power or a power outage.

When the micro optical filter assembly300-B is active, an actuated micro magnetic field around assembly300-B will exert mechanical forces on the magnetic tabs30-a,30-band30-c,which will cause the rotation shaft20to turn, resulting in either the micro optical filter10-aor10-bbeing placed in the optical path space to switch the optical signals. Therefore, assembly300-B has two active states. The magnetic field is configured to allow either one of the10-aor10-bto be placed on the optical path space for optical switching according to known art. The advantages300-B is to provide additional switching options.

For example, micro optical filters10-aand10-bmay 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 either10-aor10-b,the assembly300-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.

FIG. 3Cillustrates another embodiment of the micro optical filter assembly300. Assembly300-C is similar to assembly300-B and the description of embodiment of300-C will be made by comparison of the two. Referring toFIG. 3C, the assembly300-C includes 3 micro optical filters10-a,10-band10-cand one more magnetic tab30-dis added comparing to300-B. While the micro optical filters10-aand10-bare still located at the same distance from either ends of the rotation shaft20with a 180-degree angle across, the third micro optical filer10-cis located right in between them and in an orthogonal orientation to them. Likewise, the additional magnetic tab30-dis added at the end of the tail rod70b.As such, the micro assembly300-C has four magnetic tabs, with the adjacent tabs separated by 90 degrees.

Regarding the optical filters, according to one embodiment, the micro optical filters10-a,10-band10-care of same shape, dimension and weight, but with different optical characteristic. According to another embodiment, the middle micro optical filter, namely10-binFIG. 3C, may be of a different shape, dimension or weight than10-aand10-b.When the assembly300-C is inactive, micro filter10-bwill be perpendicularly suspended in the inactive space below the matrix board130with10-aand10-cbalanced on either side.

Regarding the magnetic tabs30-a,30-b,30-cand30-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 shaft20when the magnetic field is actuated. As such the assembly300-C has 3 activated state with either10-a,10-bor10-cplaced on the optical paths, which provides further switching choices for the MEMS switch100.

FIG. 3Dis a perspective view of the assembly300-D according to yet another embodiment of the present invention. Referring toFIG. 3D, the assembly300-D comprises a multi-blade array of n micro optical filters10-a,10-b. . .10-n,rotation shaft20, filter bearings50, and a micro stepper motor60. While the rotation shaft20, filter bearings50have the same functions as in embodiments3A-3C, the operation of the micro optical filter assembly300-D however does not depend on an actuated magnetic field to turn the rotation shaft20and activate of the micro optical filters. Instead, the rotation shaft20is fixedly attached to the shaft of the stepper motor60. Stepper motor60can be configured to rotate at very small angles according to known art. In the embodiment of300-D, the stepper motor60is configured to rotate to place each of the n micro optical filters10onto the optical path. When the assembly300-D is in the inactive state, micro optical filter10-a,10-b,. . . ,10-nall stay in the inactive space. When the assembly300-D is activated, the stepper motor60will place the selected filter according to the control signal provided by the controller140to the active position and angle to switch the optical signal. As people skilled in the art will appreciate, embodiment300-D further expends the number of micro optical filters that can be used in the micro optical filter unit200and provides many more switching options than the previous embodiments.

The micro optical filters10throughout embodiments300-A to300-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.

FIGS. 4A-4Care schematic side views of micro optical filters10, which are various embodiments of micro optical filters10ofFIGS. 3A-3D, according the present invention. To distinguish from the micro optical filters10a-10dillustrated inFIG. 3A-3D, the micro filters10described inFIGS. 4A-4Care denoted by10-i,10-ii,and10-iiirespectively. Now referring toFIG. 4A, the micro optical filter10-iis a micromirror. Referring toFIG. 4A, incident optical beam450consists of a number of wavelengths λ1, λ2, . . . , λn. With the reflection by micromirror10-i,incident optical beam450is switched 90 degrees up. The reflected optical beam consists of wavelengths λ1, λ2, . . . , λm, wherein, if m=n, micromirror10-ia total reflection micromirror; if m<n, micromirror10-iis a selective pass micromirror; and if m<<n, micromirror10-iis a narrow band micromirror.

InFIG. 4B, the micro optical filter10-iiis a micro lens. Referring toFIG. 4B, incident optical beam450consists of wavelengths of λ1, λ2, . . . , λnis transmitted on its free space optical path. Coating420is applied on the surface of the micro lens10-ii.With the appropriate coating420known in the art, wavelengths λ1, λ2, . . . , λiof beam470pass through micro lens10-iiand continue to travel in the same direction, whereas wavelengths λn+1, λi+2, . . . , λnof beam460are reflected 90 degrees up to transceivers on the other axis. As such, the optical signal of beam450are separated and sent to two transceivers on the X-axis and the Y-axis respectively. The design and application of coating420on micro lens10-iiis well-known in the art and people skilled in the art are able to select and apply the appropriate coating according to the range of wavelengths included in beams450,460and470.

InFIG. 4C, micro optical filter10-iiicomprises a first micro optical filter10-iii-a,a second micro optical filter10-iii-band optical coating430applied between10-iii-aand10-iii-b.The first micro optical filter10-iii-aand second micro optical filter10-iii-bare two wedge-shaped lenses with matching tilted surfaces. When put together, the matching tilted surfaces of the10-iii-aand10-iii-bwill be in full contact with each other with a titling angle θ. In between the tilted surfaces of10-iii-aand10-iii-b,coating430is applied. When incident optical beam450consisting of wavelengths of λ1, λ2, . . . , λnhits10-iii,part of the wavelengths will hit the coating430. Similar to embodiment4B, coating430is configured to reflect some wavelength components and pass others. In the present embodiment, wavelengths λ1, λ2, . . . , λiof beam470pass through micro lens10-iii-aand10-iii-b,whereas wavelengths λi+1, λi+2, . . . , λnof beam460are reflected. However, due to the tilting angle θ, beam460is reflected in an angular way to the side as illustrated inFIG. 4C. People skilled in the art will appreciate that, with the tilting angle θ, the reflected beam460can reach transceivers that are not in an optical path that is orthogonal to the incident beam. With the adjustment of the tilting angle θ, the receiving transceiver can be selected, thereby providing more flexibility in the implementation of the MEMS optical switch.

The embodiments of micro optical filters10-iiiillustrated inFIGS. 4A-4Ccan be applied in any combination to the assembly300inFIGS. 3A-3D. People skilled in the art will also appreciate the embodiments inFIGS. 4B and 4Cwill also enable adjustable power splitter ratio, signal monitoring and tapping by choosing the appropriate micromirrors or lenses that allows for different wavelengths of the incident beams to be reflected and pass the micro optical filter.

The MEMS switch100illustrated inFIG. 1is a two-dimension switch with m xn micro optical filter units. The optical paths are all on the same 2D X-Y plane as illustrated therein. When m and n become big, the size of the MEMS switch100will increase accordingly. However, when the optical signals travel in the free space over a longer distance, the signal intensity and quality decreases rapidly. To solve the problem, a plurality of MEMS switch100as illustrated inFIG. 1may be stacked together forming a 3D switch, which will be described in more detail below.

FIG. 5is a schematic perspective view of a 3D MEMS micro optical filter switch according to an embodiment of the present invention. Referring toFIG. 5, the 3D MEMS micro optical filter switch100-3D (hereinafter “the MEMS switch100-3D”) comprises l layers of micro optical filter matrixes120with m×n micro optical filter units located on matrix boards130stacked on top of each other. The MEMS switch100-3D can have as many as 2(m×l+n×l) transceivers transmitting and receiving optical signals at the same time (not shown inFIG. 5). There are m×n×l cross points in the 3D micro optical filter switch, wherein each cross point has a micro optical filter unit200located therein for switching. Each of the l layer of the 3D micro optical filter switch comprises m+n pairs of transceivers and operates in the same manner of the MEMS switch100as illustrated inFIG. 1. However, inter-layer transmission can also be achieved if special micro optical filters such as the one disclosed inFIG. 4Care used. By adjusting the tilting angle θ as described in connection withFIG. 4C, the reflective optical signals may go to a transceiver in a different layer in the 3D switch. As such, the 3D micro optical filter switch can be constructed. The inter-layer transmission will further increase the flexibility of the MEMS switch100-3D.

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 inFIGS. 4A-4C

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 to3D 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.