Abstract:
A micro electromechanical (MEMS) electromagnetic optical switch capable of redirecting light signals to a plurality of different output structures. The optical switch utilizes a movable mirror to redirect light signals. The mirror is magnetically moved into a predetermined fixed position by a magnetic member such that the mirror is positioned to redirect a light signal into one of a plurality of output structures. An electrical assembly induces a temporary magnetic field across the magnetic member to initiate the movement of the mirror.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. The Field of the Invention  
           [0002]    This invention relates generally to the field of optical switching devices for use in optical networks. In particular, embodiments of the present invention relate to a micro electromechanical magnetically controlled optical switch that is particularly useful for switching optical signals between a plurality of optical fibers.  
           [0003]    2. The Relevant Technology  
           [0004]    Fiber optics are increasingly used for transmitting voice and data signals. As a transmission medium, light provides a number of advantages over traditional electrical communication techniques. For example, light signals allow for extremely high transmission rates and very high bandwidth capabilities. Also, light signals are resistant to electromagnetic interference that would otherwise interfere with electrical signals. Light also provides a more secure signal because it does not emanate the type of high frequency components often experienced with conductor-based electrical signals. Light also can be conducted over greater distances without the signal loss typically associated with electrical signals on copper conductor.  
           [0005]    Many conventional electrical networks are being upgraded to optical networks to take advantage of the increased speed and efficiency. One of the many required components of an optical network is an optical switching device. An optical switching device has the capability of switching an individual light signal between at least two different locations. Usually the optical signal is first demultiplexed or dispersed and the individual channels are switched and routed to specific locations. It is preferable to optically switch the optical signals rather than converting them to electrical signals and then switching them with conventional electrical switching techniques.  
           [0006]    The field of optical switching has progressed rapidly in the last decade. For large bandwidth applications, it is important that the optical switches be extremely small to allow many channels to be switched in a relatively small amount of space. The newest types optical switches fit into the general category of micro-electromechanical systems (MEMS). The size of these devices is typically on the order of microns. Three narrower categories of MEMS optical switches have emerged as the most promising design configurations: piezoelectric, electrostatic and electromagnetic. All of these switches utilize micro-mirrors to switch or reflect an optical channel or signal from one location to another depending on the relative angle of the micro-mirror. Because of the small size of optical MEMS switches, it is important to design a switch that is durable, consumes little power and can generate a sufficient amount of power to rotate the mirror. Durability is important because, over the lifetime of a switch, it is quite common for dust and other debris particles to pass within the switch. Power consumption in optical switches must be minimized because optical switches are usually in operation at all times and therefore any unnecessary power consumption is a significant waste of resources. It is also important for the optical switch design to be capable of generating sufficient forces to rotate the mirror within a large range of angles.  
           [0007]    Piezoelectric switches utilize piezoelectric materials to change shape proportionally to how much electrical voltage is applied to them. The mirror is then attached to the piezoelectric material, which can be manipulated by applying varying degrees of electrical voltage. Unfortunately, piezoelectric materials used in optical switches tend to require relatively high (100V range) voltages to produce relatively small motions, which limit the angular range the mirror is capable of achieving. Piezoelectric materials also tend to be somewhat fragile and susceptible to long term drift.  
           [0008]    Electrostatic switches are currently the most popular form of MEMS optical switches. These switches utilize the small electrostatic force produced by a diamagnetic material when an electrical field is induced upon it. Unfortunately, electrostatic optical switches require high voltages (high by 3V CMOS standards but generally less than required to actuate piezoelectric switches) and produce relatively small forces. This means that it is difficult to design an individual electrostatic optical switch that is capable of switching between a large number of fibers. For this reason, electrostatic optical switches are typically used in large arrays. In addition, these switches tend to be fragile to foreign particulates and sensitive to moisture.  
           [0009]    Electromagnetic switches are the last category of typical MEMS optical switches. This form of optical switch is rarely used despite the numerous advantages they possess over other types of MEMS switches. Electromagnetic optical switches tend to utilize ferromagnetic materials to rotate and manipulate the angle of the mirror. Ferromagnetic materials are easily magnetized and are capable of producing large forces. A hard ferromagnetic material has a wide hysteresis curve (B v H or Magnetic curve) and therefore has the ability to generate remnant magnetization even after an external magnetic field is turned off. For this reason, hard ferromagnetic materials are commonly used to make permanent magnets. A soft ferromagnetic material has a relatively narrow hysteresis curve and consequently is incapable of producing a magnetic force without an external magnetic field being applied across it. Electromagnetic optical switches are capable of generating large forces while consuming little power. In addition, electromagnetic optical switches are durable to particles that may otherwise interfere with the performance of other switches.  
           [0010]    There is a need in the industry for an efficient electromagnetic MEMS optical switch that consumes low power yet is still durable in relation to other forms of optical switches.  
         BRIEF SUMMARY OF THE INVENTION  
         [0011]    These and other problems in the prior art are addressed by embodiments of the present invention, which relates to a MEMS electromagnetic optical switch that generates large magnetic forces and consumes little energy.  
           [0012]    In a preferred embodiment, the electromagnetic optical switch generally comprises a reflection member rotatably coupled to a base. The optical switching function of the device is performed by rotating the reflection member to a specified angle so as to redirect an optical signal to one of a plurality of output locations. The reflection member further comprises a substrate with a mirror coupled to one surface of the substrate and at least one substrate magnetic member connected to the opposite surface of the substrate. The mirror naturally reflects an incident optical signal in a direction mathematically related to the angle of the mirror itself with respect to normal. The substrate magnetic members are permanent ferromagnetic magnets.  
           [0013]    In a preferred embodiment, the electromagnetic optical switch further comprises a plurality of magnetic members and a plurality of electrical assemblies. The magnetic members are preferably formed from a hard ferromagnetic material with a high saturation point and a low coercivity. The magnetic members are disposed in substantial alignment with the substrate magnetic members of the reflection member. The electrical assemblies are further comprised of a conductor, a switch and a source. The conductor is configured to apply a magnetic field across one of the plurality of magnetic members when a current is induced through the conductor. The conductor is electrically connected to the source. The switch is disposed on the electrical connection between the conductor and the source so as to control the current flow from the source to the conductor.  
           [0014]    In one preferred embodiment, the electromagnetic optical switch is operated by magnetically rotating the reflection member so as to deflect incident optical signals to a desired output location. This is accomplished by first switching the switch to electrically connect the source to the conductor of the electrical circuit. This causes a magnetic field to be generated across the corresponding magnetic member. The corresponding magnetic member then creates a magnetic force upon the corresponding substrate magnetic member. This force is either an attraction or a repulsion force depending on the desired angle of the reflection member. Since there are multiple groupings of corresponding magnetic members, electrical circuits and substrate magnetic members, the attraction or repulsion force generated by each grouping depends on the desired position of the reflection member.  
           [0015]    The foregoing, together with other features and advantages of the present invention, will become more apparent when referred to the following specification, claims and accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    In order that the manner in which the above-recited and other advantages and features of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:  
         [0017]    [0017]FIG. 1 illustrates a cross-sectional profile view of one embodiment of an electromagnetic optical switch containing lower stops;  
         [0018]    [0018]FIG. 2 illustrates a cross-sectional profile view of an alternative embodiment of an electromagnetic optical switch containing lower and upper stops;  
         [0019]    [0019]FIG. 3 illustrates a cross-sectional profile view of yet another alternative embodiment of an electromagnetic optical switch containing magnetic bit stops;  
         [0020]    [0020]FIG. 4 illustrates a cross-section profile view of still another alternative embodiment of an electromagnetic optical switch without stops;  
         [0021]    [0021]FIG. 5 illustrates a three-dimensional perspective view of a presently preferred embodiment of an electromagnetic optical switch.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    Reference will now be made to the drawings to describe presently preferred embodiments of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of the presently preferred embodiments, and are not limiting of the present invention, nor are they necessarily drawn to scale.  
         [0023]    In general the present invention relates to an optical switch that utilizes ferromagnetic materials and magnetic fields for rotating and manipulating a mirror within a particular range of motion. As will be described in further detail below, the optical switch is capable of redirecting optical signals from one optical fiber to one of a plurality of other optical fibers. Also, while embodiments of the present invention are described in the context of fiber optic switching mechanisms, it will be appreciated that the teachings of the present invention are applicable to other applications as well.  
         [0024]    Referring first to FIG. 1, one embodiment of an electromagnetic optical switch, designated generally at  100 , is shown. In this embodiment, the optical switch  100  includes a base  170 , a reflection member  105 , four magnetic members  115 ,  120 ,  130 ,  135 , and two electrical assemblies  160 ,  165 . The reflection member  105  further comprises a mirror  107  which is coupled to the top of a substrate  110 , a first substrate magnetic member  115 , and a second substrate magnetic member  120 . The substrate magnetic members  115 ,  120  are coupled to the bottom of the substrate  110 . The substrate magnetic members  115 ,  120  are formed from a hard ferromagnetic material with a high saturation point and a low coercivity, wherein the magnetic members  115 ,  120  have previously been magnetized so as to form permanent magnets. A pair of flexures  125 ,  127  elastically couple the reflection member  105  to the base  170 . Flexures can be formed from any material that is capable of providing rigid yet flexible response. For example, silicon nitride is a common flexure material that can be used with the invention. Flexures  125 ,  127  represent one example of means for coupling the reflection member to the base in a manner that allows rotational motion of the reflection member and also represents an example of means for supporting the reflection member in any of a plurality of positions.  
         [0025]    As is further shown in FIG. 1, the base  170  forms a cavity  122  with a particular width and depth configured to house the reflection member  105  in the manner shown. A first and a second base magnetic member  130 ,  135  are located at the bottom of the cavity  122  such that each is approximately horizontally aligned with one of the substrate magnetic members  115 ,  120  located on the bottom of the substrate  110 . The base magnetic members  130 ,  135  rise above the bottom of the cavity  122  so as to form stops for the reflective member  105 . The base magnetic members  130 ,  135  are formed from of a hard ferromagnetic material with a high saturation point and a low coercivity.  
         [0026]    A first and a second electrical assembly  160 ,  165  are positioned to individually apply a magnetic field across the first and second base magnetic members  130 ,  135 , respectively. The electrical assemblies  160 ,  165  include an electrical conductor  140 ,  145  and an electrical circuit  150 ,  155 . The electrical conductors  140 ,  145  are configured and disposed to generate a magnetic field upon the corresponding base magnetic member  130 ,  135  when an electrical current is induced across the electrical conductors  140 ,  145 . The electrical conductors  140 ,  145  are electrically coupled to the electrical circuits  150 ,  155 . The electrical circuits  150 ,  155  further include an electrical source and a switch. In addition, the electrical circuits  150 ,  155  may be connected to external computer circuitry or contain logic circuits to efficiently control the timing and amount of electrical current placed across the electrical conductors  140 ,  145 .  
         [0027]    As is further shown in FIG. 1, the reflective member  105  can be magnetically rotated by the relative magnetic attraction and repulsion forces of base magnetic members  130 ,  135  and substrate magnetic members  115 ,  120 . The electrical assemblies  160 ,  165  generate a directional magnetic field across the corresponding base magnetic members  130 ,  135 . The magnetic field then causes the base magnetic member  130 ,  135  to generate a magnetic force. Thus, electrical assemblies  160  and  165 , as well as the other electrical assemblies disclosed herein, represent examples of means for electromagnetically moving the reflection member into a fixed position by temporarily inducing a current that initiates the movement of the reflection member.  
         [0028]    The direction of each magnetic field is based upon the desired position of the reflection member  105 . For example, if it is desired to rotate the reflection member  105  in a clockwise motion, the magnetic field generated by the second electrical circuit  165  is selected to will cause the second base magnetic member  135  to exert a magnetic attraction force upon the second substrate magnetic member  120 . Likewise, the first electrical circuit  160  generates a magnetic field across the first base magnetic member  130  such that a repulsion force is exerted upon the first substrate magnetic member  115 . When these magnetic forces are generated between the magnetic members  115  and  130  and between the magnetic members  120  and  135 , the reflective member  105  is forced to rotate in a clockwise motion. A similar configuration can be used to rotate the mirror in a counter-clockwise motion.  
         [0029]    The mirror can be flattened and aligned horizontally by configuring both electrical assemblies  160 ,  165  to generate a magnetic field in the same direction. This causes both base magnetic members  130 ,  135  to exhibit the same direction of force upon the corresponding substrate magnetic members  115 ,  120 . Thereby, the mirror is horizontally aligned. It should be noted that since the base magnetic members  130 ,  135  are formed from a hard ferromagnetic substance, the electrical circuits  160 ,  165  only need to pulse a magnetic field across the base magnetic members to induce a magnetic force to be exerted by the base magnetic members  130 ,  135 . Likewise, when it is necessary to change the orientation of the reflection member  105 , the electrical circuits only need to pulse a new magnetic field across the base magnetic members to alter the magnetic force generated by the base magnetic members  130 ,  135 . The pulsed magnetic fields generated by the electrical assemblies  160 ,  165  cause the base magnetic members  130 ,  135  to change their position on a hysteresis curve and, when the magnetic field is removed, the base magnetic members  130 ,  135  relax to a new position on the hysteresis curve. Considerable power consumption is saved by utilizing the remnant magnetization properties of the hard ferromagnetic base magnetic members  130 ,  135  in this way.  
         [0030]    Reference is next made to FIG. 2, wherein an alternative embodiment of an electromagnetic optical switch, designated generally at  200 , is shown. Many of the components that make up the optical switch  200  are described in more detail with reference to FIG. 1. This embodiment of the electromagnetic optical switch  200  utilizes four nonmagnetic stops  220 ,  225 ,  255 ,  260  to brace and prevent over-rotation of the reflection member  234 . This additional bracing of the reflection member  234  helps to prevent misalignment when an optical signal is being redirected to another fiber. The non-magnetic stops  220 ,  225 ,  255 ,  260  are formed from a non-magnetic material that will not damage the reflection member upon contact.  
         [0031]    Similar to FIG. 1, the reflection member  234  includes mirror  232 , a substrate  230  and two substrate magnetic members  235 ,  240 . The substrate magnetic members  235 ,  240  are formed from of a pre-magnetized hard ferromagnetic substance. Also similar to FIG. 1, a pair of flexures  243 ,  245  are used to elastically couple the reflection member  234  to a base  212 . The base  212  contains a cavity  242  with a particular length and width to house the reflection member  234  as shown. Unlike FIG. 1, this embodiment of the electromagnetic optical switch  200  has a first assembly  210  and a second assembly  215 . The assemblies  210 ,  215  are shaped and coupled to the base  212  in a manner to increase the height of the cavity  242 . The assembly stops  220 ,  225  are secured to the lower portion of the corresponding assemblies  210 ,  215  such that when the reflection member  234  is rotated in either a clockwise or counter-clockwise motion, the assembly stops  220 ,  225  prevent further rotation of the reflection member  234  in that direction. FIG. 2 illustrates the second assembly stop  225  preventing the reflection member  234  from rotating in a counter-clockwise motion.  
         [0032]    As is also shown in FIG. 2, the electrical assemblies  287 ,  292  and base magnetic members  275 ,  270  are located under the bottom of the cavity  242 . Similar to FIG. 1, the electrical assemblies  287 ,  292  are include of electrical conductors  265 ,  280  and electrical circuits  285 ,  290 . Unlike FIG. 1, the electrical conductors  265 ,  280  in this embodiment are shown to be stacked rather than wrapped around the base magnetic members  275 ,  270 . This configuration also enables the electrical assemblies  287 ,  292  to create a magnetic field across the base magnetic members  275 ,  270 . The base magnetic members  275 ,  270  are formed from a hard ferromagnetic material with a high saturation point and a low coercivity such that they exhibit remnant magnetization properties even after a magnetic field is turned off. Unlike FIG. 1, this embodiment contains two base stops  255 ,  260 , which are secured to the upper potion of the base  212  within cavity  242 . The base stops  255 ,  260  act in the same manner as the assembly stops  220 ,  225  such that they prevent the further rotation of the reflection member  234  in either a clockwise or counter-clockwise motion. FIG. 2 shows the first base stop  255  preventing the reflection member  234  from further rotating in a counter-clockwise motion. The operation of this embodiment of the electromagnetic switch  200  is similar to the embodiment shown in FIG. 1 except for the addition of the assembly stops  220 ,  225 .  
         [0033]    Reference is next made to FIG. 3, wherein yet another embodiment of an electromagnetic optical switch, designated generally at  300 , is shown. Many of the components that make up the electromagnetic optical switch  300  are described in more detail with reference to FIG. 1. The embodiment shown in FIG. 3 utilizes four magnetic stops  315 ,  320 ,  350 ,  355  that prevent over-rotation of the reflection member  344  and secure the reflection member  344  in a particular position. Unlike FIGS. 1 and 2, the base magnetic members  360 ,  365  in this embodiment are formed from a soft ferromagnetic material that does not exhibit remnant magnetization properties. Similar to FIGS. 1 and 2, the reflection member  344  includes a mirror  342 , a substrate  345  and two substrate magnetic members  335 ,  340 . But unlike FIGS. 1 and 2, the reflection member  344  also contains two side magnetic members  325 ,  330  formed form a pre-magnetized hard ferromagnetic material. The base  312  contains a cavity  352  with a particular length and width to house the reflection member  344  as shown.  
         [0034]    Similar to FIG. 2, the electromagnetic optical switch  300  further comprises a first assembly  305  and a second assembly  310  that are shaped and configured to fit on top of the base  312  and to increase the height of the cavity  352 . Also similar to FIG. 1, a pair of flexures  361  and  362  are used to elastically couple the reflection member  344  to the base  312 . The assembly stops  315 ,  320  are secured to the lower portion of the assemblies  305 ,  310 , such that when the reflection member  344  is rotated in either a clockwise or counter-clockwise motion, the assembly stops  315 ,  320  prevent further rotation of the reflection member  344  in that direction. In addition to preventing further rotation, the assembly stops  315 ,  320  magnetically secure the reflection member  344  at a particular location. This is accomplished by the magnetic attraction force between the side magnetic members  325 ,  330  and the assembly stops  315 ,  320 . FIG. 3 illustrates the first assembly stop  315  preventing the reflection member  344  from rotating in a counter-clockwise motion and magnetically securing the reflection member  344  in that position.  
         [0035]    As is also shown in FIG. 3, the electrical assemblies  387 ,  392  are located under the bottom of the cavity  342 . Similar to FIGS. 1 and 2, the electrical assemblies  387 ,  392  include of electrical conductors  370 ,  375  and electrical circuits  380 ,  385 . The base magnetic members  360 ,  365  are formed from a soft ferromagnetic material that does not exhibit remnant magnetization properties after a magnetic field is turned off. Similar to FIG. 2, this embodiment also contains two base stops  350 ,  355 , which are secured to the lower potion of the base  312  cavity  352 . The base stops  350 ,  355  act in the same manner as the assembly stops  315 ,  320 , such that they prevent the further rotation of the reflection member  344  in either a clockwise or counter-clockwise motion and also magnetically secure the reflection member  344  in a particular position. FIG. 3 shows the second base stop  355  preventing the reflection member  344  from further rotating in a counter-clockwise motion. The second base stop  355  is also magnetically bonding with the second side magnetic member  330  of the reflection member  344  so as to secure the reflection member in a particular position.  
         [0036]    The operation of this embodiment of the electromagnetic switch  300  is similar to the embodiment shown in FIG. 2 except the stops  315 ,  320 ,  350 ,  355  are magnetic and the base magnetic members  360 ,  365  are formed from a soft ferromagnetic material. When a magnetic field is induced across the base magnetic members  360 ,  365  in this embodiment, they generate an attraction or repulsion magnetic force in the same manner as described with reference to FIG. 1. But unlike FIG. 1, when the magnetic fields generated by the electrical assemblies  387 ,  392  are turned off, the base magnetic members  360 ,  365  no longer generate a magnetic force. The reflection member  344  is held in place by the magnetic attraction force between the stops  315 ,  320 ,  350 ,  355  and the side magnetic members  325 ,  330 . When a different magnetic field is induced across the base magnetic members  360 ,  365 , the base magnetic members  360 ,  365  generate a magnetic attraction or repulsion force large enough to overcome the magnetic attraction force between the stops  315 ,  320 ,  350 ,  355  and the side magnetic members  325 ,  330 .  
         [0037]    Reference is next made to FIG. 4, wherein yet another embodiment of an electromagnetic optical switch, designated generally at  400 , is shown. Many of the components that make up the electromagnetic optical switch are described in more detail with reference to FIG. 1. The embodiment of an electromagnetic optical switch  400  shown in FIG. 4 is similar to FIG. 1 except that switch  400  does not contain any stops for securing the reflection member  405  in a particular position. Instead, the magnetic forces generated by the base magnetic members  430 ,  435  are be precisely controlled so as to properly align the reflection member  405  in the desired position. Similar to FIGS.  1 - 3 , the reflection member  405  includes a mirror  407 , a substrate  410  and two substrate magnetic members  415 ,  420 . The substrate magnetic members  415 ,  420  are formed from of a pre-magnetized hard ferromagnetic substance. Also similar to FIG. 1, a pair of flexures  425 ,  427  are used to elastically couple the reflection member  405  to a base  470 .  
         [0038]    As is further shown in FIG. 4, the base  470  forms a hollow cavity  422  with a particular width and depth configured to house the reflection member  405  in the manner shown. A first and a second base magnetic member  430 ,  435  are located at the bottom of the cavity  422  such that they are each approximately horizontally aligned with one of the substrate magnetic members  415 ,  420  located on the bottom of the substrate  410 . A first and a second electrical assembly  460 ,  465  are positioned to individually apply a magnetic field across the first and second base magnetic members  430 ,  435  respectively. The electrical assemblies  460 ,  465  include an electrical conductor  440 ,  445  and an electrical circuit  450 ,  455 . Unlike FIG. 1, the electrical assemblies  450 ,  455  comprise an electrical source, a switch, a thermal compensation circuit, and an alignment circuit. In addition, the electrical circuits  450 ,  455  may be connected to external computer circuitry or contain logic circuits to efficiently control the timing and amount of electrical current placed across the electrical conductors  440 ,  445 .  
         [0039]    Since the embodiment shown in FIG. 4 does not contain any stops to help align the reflection member  405 , it is necessary to utilize additional components in the electrical circuits  450 ,  455 . The alignment circuit executes an alignment algorithm that utilizes optical feedback to determine the best angle for the reflection member  405 . Upon completion, the algorithm stores the electrical signals necessary to generate the magnetic field upon the base magnetic members  430 ,  435  that will generate the necessary magnetic force upon the substrate magnetic members  415 ,  420  so as to position the reflection member  405  at the proper angle.  
         [0040]    The thermal compensation circuit senses thermal disturbances that would potentially affect the angle of the reflection member. Upon sensing these disturbances, the thermal compensation circuit adjusts the electrical signals to correct for the disturbance. Additional circuits may be included in the electrical circuits  450 ,  455  so as to ensure proper alignment and calibration of the electromagnetic optical switch  400 . Other than the additional electrical components and the lack of stops, the operation of electromagnetic optical switch  400  is similar to the embodiment described with reference to FIG. 1.  
         [0041]    Reference is next made to FIG. 5, wherein a presently preferred embodiment of an electromagnetic optical switch, designated generally at  500 , is shown. Many of the components that make up the electromagnetic optical switch  500  are described in more detail with reference to FIG. 1. FIG. 5 shows a three-dimensional view of electromagnetic optical switch  500 . The reflection member  505  is suspended by two sets of torsion bars  515 ,  517 , such that the reflection member can be rotated into almost any three-dimensional position. The torsion bars  515 ,  517  can be rotated but not bent. The torsion bars  515 ,  517  behave like a spring, such that they spring back to a normalized position when a force is removed from them. Torsion bars  515 ,  517  represent another example of means for coupling the reflection member to the base in a manner that allows rotational motion of the reflection member and also represents another example of means for supporting the reflection member in any of a plurality of positions. In general, the flexures and torsion bars, as well as other structures that perform the equivalent function of coupling the reflection member to the base can be used according to the invention.  
         [0042]    Similar to FIGS.  1 - 4 , the reflection member  505  includes a mirror  507 , a substrate  509 , and two substrate magnetic members  510 ,  512 . The two magnetic members  510 ,  512  are located along a plane that is perpendicular to the axis defined by the inner torsion bars  515 . In this embodiment, an outside ring  520  allows for rotation with two degrees of freedom. The outside ring  520  is rotatably coupled to the reflection member  505  via the inner torsion bars  515 . The outside ring  520  is rotatably coupled to the base  540  via the outside torsion bars  517 . The inner torsion bars  515  have an axis of rotation that is perpendicular to the axis of rotation of the outer torsion bars  517 . In addition, the outside ring  520  contains two ring magnetic members  525 ,  527  that are formed from pre-magnetized hard ferromagnetic substances. The magnetic members  525 ,  527  are located along a plane that is perpendicular to the axis of rotation of the outer torsion bars  517 .  
         [0043]    As is further shown in FIG. 5, the base  540  forms a cavity  542  that has a particular height and width to house the reflection member  505  and the outside ring  520  in the manner shown. At the bottom of the cavity are located four base magnetic members (not shown) that correspond to the two substrate magnetic members  510 ,  512  and the two ring magnetic members  525 ,  527 . In addition, four electrical assemblies (not shown) are also located at the bottom of the cavity  542  and are positioned to individually apply a magnetic field upon one of the base magnetic members (not shown).  
         [0044]    In operation, the electromagnetic optical switch  500  shown in this embodiment operates similarly to the embodiments described in reference to FIGS.  1 - 4 . The four electrical assemblies (not shown) generate a magnetic field that causes the base magnetic members (not shown) to generate a magnetic force upon either the substrate magnetic members  510 ,  512  or the ring magnetic members  525 ,  527 . This magnetic force can be used to position the reflection member  505  at selected angular positions defined by the rotation about the two axes of rotation almost any three dimensional angle. Similar to the embodiment shown in FIG. 4, this embodiment does not contain stops to help align the reflection member and prevent over-rotation. Because of this, additional electrical components, such as thermal compensation and calibration circuits can be used to precisely align the reflection member  505  as described above in reference to FIG. 4. The embodiment of FIG. 5 provides the benefit of switching between a large number of fibers, whereas the embodiments shown in FIGS.  1 - 4  are generally limited to fewer fibers.  
         [0045]    The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.