WO2002023241A1

WO2002023241A1 - Opto-mechanical switch

Info

Publication number: WO2002023241A1
Application number: PCT/US2000/035324
Authority: WO
Inventors: Nobuyuki Tanaka
Original assignee: Opient, Inc.
Priority date: 2000-09-15
Filing date: 2000-12-22
Publication date: 2002-03-21
Also published as: AU2001225991A1

Abstract

An opto-mechanical switch (801) selectively redirects signals traveling through two inputs (803, 805) and two outputs (813, 815) of the switch. The opto-mechanical switch (801) includes a center member (819) that selectively aligns switch fibers (821, 823, 825, 827) which control the path of input signals in response to a control signal. The input and output optical fibers (821, 823, 825, 827) are mounted in blocks (863) that slide against the center member (819). The opto-mechanical switch (801) utilizes rods (891) which engage grooves (865) which provide stops for aligning switch fibers (821, 823, 825, 827) in the center member (819) with the input and output fiber.

Description

OPTO-MECHANICAL SWITCH FIELD OF THE INVENTION

The present invention relates generally to opto-mechanical switches for optical fiber communications systems.

BACKGROUND OF THE INVENTION

Optical fiber communications systems carry many muxed light signals within a single optical fiber. This muxing of optical signals is known as "wavelength division multiplexing", WDM. The optical fibers are connected to each other at optical nodes to form optical networks.

Referring to Figures 1 A a simple "point to point" network includes two optical nodes 105 connected to the ends of an optical fiber 103. Data signals are converted into light signals at a first node 105 and are transmitted through the optical fiber 103. The light signals are received at the second node 105. Light signals can currently travel a few hundred miles through an optical fiber before the signal becomes too weak to identify. At the second node 105 the signal may be converted into an electrical signal or amplified and retransmitted before reaching its final destination. Referring to Figures IB and 1C, more complex optical networks can be constructed with switching devices at the nodes 105 that are connected to multiple fibers 103. Figure IB illustrates a "ring" type network. The circular configuration of the ring network allows signals to be transmitted between any two nodes 105 even if there is a break in a single fiber 103 of the network. This redundancy of data transmission paths provides a backup that allows for breaks in an optical fiber 103 or maintenance to be performed without interrupting operation of the rest of the network. Figure 1C illustrates a "mesh" type network which provides further redundancy of transmission paths. In the mesh network, optical fibers 103 as well as nodes 105 may be taken out of service without interrupting the operation of the rest of the network. A variety of processes may occur at the nodes of the network. Weak signals may be amplified. Individual signals may be added and muxed into a single fiber with other signals traveling through the same optical fiber of the network. Other individual signals may be removed or dropped from the network. The nodes may also include many switches which control the direction of individual signals through the network. Where many individual muxed signals are traveling through a single fiber but have separate destinations, the individual signals must separated and individually switched at the nodes.

Referring to Figure 2, a prior art optical switch system 201 is illustrated. The first group muxed input signals each having a different frequency travel together through a first input fiber 211 to a first demuxing device 215 and a second group of muxed input signals are transmitted through a second input fiber 209 to a second demuxing device 213. The demuxing devices 213, 215 separate the muxed signals into individual frequencies or signals. The individual signals exit the demuxing devices 213, 215 and pass through individual fibers to dedicated switches 217 for each signal. The switches 217 each have two positions and are individually actuated. In the first position, the switches 217 transmit signals from the first demuxing device 211 to the first muxing device 219 and signals from the second demuxing device 213 to the second muxing device 221. In the second position, the paths of the signals are switched. The switches 217 transmit signals from the first demuxing device 215 to the second muxing device 221 and signals from the second demuxing device 213 to the first muxing device 219. The muxing devices 219, 221 remux the output signals from the switches 217 and transmit the muxed signal through the associated output fibers 225, 227.

There are two broad categories of optical switches: optical - electric - optical (OEO) switches and all optical switches. The OEO switch first receives a muxed optical signal and separates the individual optical signals. The individual light signals are converted into electrical signals which are individually switched to their desired paths. The elpctrical signals are then converted into light signals muxed and retransmitted through another optical fiber. The OEO switches require complex and expensive equipment.

There are several variations of all optical switches: micro electro mechanical machines (MEMs), liquid crystals, bubbles, or thermo-optical. MEMs utilize an array of tiny mirrors that are tilted to switch beams of light from one fiber to another. Liquid crystal switches transmit light through a liquid crystal structure which polarizes the light and switches the light in different directions depending upon the polarization. Bubble switches utilize bubbles which act like mirrors to switch the light signals. Thermo-optical switches utilize a structure having a thermally variable refractive index to switch the light signals.

SUMMARY AND OBJECTS OF THE INVENTION

It is an object of embodiments of the invention to provide a compact and fast acting all-optical switch that allows the user to remotely direct optical signals in a multichannel optical network system. It is a further objective of the invention to provide an optical switch having an actuator which controls the position of the switch in response to a remote control signal.

In an embodiment, the opto-mechanical switch may have a cubic shape and have two input fibers and two output fibers mounted around four sides and a center member mounted between the input and output fibers. The center member has switch fibers which are aligned with the input and output fibers to control the paths of signals through the switch. The switch directs the input signals through one of two paths depending upon the position of the switch. In the "off position, the center member aligns a first set of switch fibers with the inputs and outputs, such that signals from the first input exits the first output and signals from the second output exit the second output. In the "on" position, the center member aligns a second set of switch fibers with the inputs and outputs such that signals from the first input exit the second output and signals from the second input exit the first output.

In one embodiment of the present invention, the input and output fibers are each mounted in blocks which may contact planar side surfaces of the center member. In order to reduce the signal losses through the switch, the gap between the input and output fibers and the switch fibers may be minimized by compressing the blocks containing the input and output fibers against the center member. The blocks may be compressed against the center member with springs. In an embodiment, the actuator and optical switch components including input and output fiber blocks and the center member are mounted in a package which is board mountable and easily connected in a modular manner to other optical devices mounted in similar packages. By connecting various packages, complex optical systems can be constructed. The package configuration also allows the actuators and switch components to be easily removed from an optical system without requiring the disassembly of connected packages.

In an embodiment, the opto-mechanical switch may include alignment rods which may be used to simplify the alignment of input and output fibers with the switch fibers. Alignment rods may protrude from the input and output fiber blocks. The alignment rods may engage vertical slots in the center member which limit the movement of the center member relative to the input and output fibers. When the rods are stopped at one end of the slots, the input and output fibers are aligned with one set of switch fibers and when the rods are stopped at the opposite end of the slots, the input and output fibers are aligned with a second set of switch fibers.

In yet another embodiment of the optical switch, the optical fibers and rods may be secured to V-groove blocks with covers. The input fibers, output fibers and alignment rods may be mounted in V-groove blocks around the center member and the switch fibers may be mounted in V-groove blocks in the center member. The rods may engage slots in the center member and limit the travel of the center member. The slots may be formed by removing material between adjacent grooves in the V-groove blocks and placing a cover over the expanded groove. In an embodiment, the optical fibers may have a coating or protective covering that may be removed at the ends so that only the raw optical fiber is secured in the V-groove blocks. In another embodiment, the ends of the optical fiber components may be mounted in ferrules or tube structures and a flexible elastomer may cover the center portion of the optical fiber. The ferrules or tube structures may be secured to the input blocks, the output blocks and the center member of the opto-mechanical switch. Further, the ferrules and tube structures may function as optical fiber connectors. The ferrules or tube structures of two optical fibers may be placed in a V-groove such that the ends contact each other and are secured in place with a cover or any other fastening mechanism. This optical fiber connector may also be used to interconnect optical component packages. In another embodiment, the optical switch fibers are covered with a flexible protective material and ferrules are mounted on the ends forming optical switch fiber assemblies. The input and output fibers of the switch are mounted in center grooves of input and output V-groove blocks. When the switch is in the off position, the "off switch fiber assemblies are aligned with the input and output fibers by placing the "off switch fiber assemblies in the center grooves of the input and output V-groove blocks. Similarly, in the switch's on position, the "on" switch fiber assemblies are placed in the center grooves of the input and output V-groove blocks.

Other objects, features, and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows below. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and should not be limited to the embodiments in the figures of the accompanying drawings, in which like references indicate similar elements, and in which: Figure 1 A illustrates a point to point optical network;

Figure IB illustrates a ring type optical network;

Figure 1C illustrates a mesh type optical network;

Figure 2 illustrates an optical - electrical - optical transponder;

Figure 3 A illustrates a sectional view of an embodiment of the optical switch in the off position;

Figure 3B illustrates a sectional view of an embodiment of the optical switch in the on position;

Figure 4 illustrates a view of the center member of the optical switch in accordance with an embodiment of the present invention; Figure 5 A illustrates a view of an embodiment of the optical switch in the off position;

Figure 5B illustrates a view of an embodiment of the optical switch in the on position;

Figure 6 illustrates an actuator mounted on the switch according to an embodiment of the present invention;

Figure 7 illustrates an embodiment of the present invention having the switch and actuator mounted in a modular package; Figure 8 illustrates an embodiment of the present invention that includes input fibers and output fibers mounted in blocks which contact a center member having switch fibers;

Figure 9 illustrates an embodiment of the center member; Figure 10 illustrates an array of connected optical switches in accordance with an embodiment of the present invention;

Figure 11 illustrates a cross section of an embodiment of an optical fiber assembly;

Figure 12 illustrates a group of optical component packages interconnected with optical fiber assemblies;

Figure 13 illustrates a modular embodiment of the opto-mechanical switch;

Figures 14A and 14B illustrate an input V-groove block of an opto-mechanical switch according to an embodiment of the present invention;

Figures 15A and 15B illustrate a sectional side view of the input V-groove block of an opto-mechanical switch in accordance with an embodiment of the present invention;

Figures 16A and 16B illustrate a sectional side view of the input V-groove block in accordance with an alternate embodiment of the present invention;

Figure 17 illustrates an embodiment of the present invention that includes input fibers, output fibers switch fibers are mounted in sliding optical fiber switch blocks; and

Figure 18 illustrates an array of optical switches in combination with muxing and demuxing devices according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

An optical wavelength opto-mechanical switch is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident, however, to one of ordinary skill in the art, that the present invention may be practiced without these specific details. The description of preferred embodiments is not intended to limit the scope of the claims appended hereto.

Opto-mechanical switches are used with optical networks to route optical signals. Many individual signals may travel through a single optical fiber. The input signals traveling through a single optical fiber may include up to 32 frequencies each transmitting data at up to 40 GB/s. In the future 80-128 or more channels of data may be transmitted through a single optical fiber. The transmitted signals may be digital signals. The inventive wavelength switch is frequency specific and is compatible with all types of digital signals. Sectional top views of an embodiment of the two position opto-mechanical switch 301 are illustrated in Figures 3A and 3B. The switch 301 has two inputs 303, 305 mounted on adjacent side walls (top and left sides) of the switch 301 and two outputs 313, 315 mounted on the opposite side walls (bottom and right sides). The switch 301 has a center member 319 containing four switch fibers 321, 323, 325, 327 which are selectively used to direct optical signals depending upon the position of the switch 301. In Figure 3A, the switch 301 is illustrated with the center member 319 in the "off position. Switch fiber 321 is aligned between the first input 303 and the first output 313 so that signals traveling through the first input 303 pass through the switch fiber 321 and are directed to the first output 313. Similarly, switch fiber 323 is aligned between the second input 305 and the second output 315 so that signals traveling through the second 305 input are directed through the switch fiber 323 to the second output 315. In Figure 3B the switch is illustrated in the "on" position. Input signals traveling through the first input 303 pass through switch fiber 325 and are directed to the second output 315. Signals traveling through the second input 305 pass through switch fiber 327 and are directed to the first output 313.

The opto-mechanical switch 301 toggles between the "off and "on" positions by moving the center member vertically relative to the input and output fibers. Figure 4 illustrates an embodiment of the center member 319 in more detail. The switch fibers 321, 323 are mounted within the center member 319 and are aligned with the input and output fibers (not shown) when the switch is in the off position. The ends of the switch fibers 321, 323 cross each other and intersect opposite side surfaces of the center member 319. The end of the switch fibers 321, 323 may intersect the sides of the center member 319 at the same vertical position such that the intersection points define a first plane 431.

Switch fibers 325, 327 are also mounted within the center member 319 and may be aligned with the input and output fibers (not shown) when the switch is in the "on" position. The ends of the switch fibers 325, 327 intersect adjacent side surfaces of the center member 319 and do not intersect each other. Similarly, the ends of the switch fibers may intersect the sides of the center member 319 at the same vertical position that defines a second plane 433. The second plane 433 defined by the ends of switch fibers 325, 327 may be substantially parallel to the first plane 431 defined by the ends of switch fibers 321, 323. In Figures 5 A and 5B, an embodiment of the opto-mechanical switch 501 is illustrated. The input fibers 303, 305 and output fibers 315, 313 are mounted within side walls of the switch 501 and the center member 319 is movable in the vertical axis within the switch 501. Figure 5 A illustrates the center member 319 in the "off position with the center member 319 in a lower position. The center member 319 is positioned in the switch 501 such that the first plane 431 is aligned with the input fibers 303, 305 and the output fibers 313, 315. As discussed with reference to Figure 3 A, signals traveling through input fiber 303 exit output fiber 313 and signals traveling through input fiber 305 exit output fiber 315. Figure 5B illustrates the switch 501 in the "on" position with the center member 319 moved into an upper position. The second plane 433 of the center member 319 is aligned with the input 303, 305 and the output fibers 313, 315. As discussed with reference to Figure 3B, in the "on" position signals from the input fiber 303 pass through switch fiber 325 to the output fiber 315 and signals from the input fiber 305 pass through the switch fiber 327 to the output fiber 313.

In Figure 6, an embodiment of the opto-mechanical switch 601 having an actuator 651 is illustrated. In this embodiment, the actuator moves the center member (not shown) between the "off and "on" positions by an actuator 651. The actuator 651 may be a fast acting electro-mechanical device, such as a solenoid or any other fast acting actuator. Due to the high optical data transmission rate requirements, the switching speed may be less than 5 milliseconds. In an embodiment, the actuator 651 may also have a latching mechanism which keeps the center member switched in its last position even if power to the actuator 651 is cut off. This feature helps to maintain the flow of information through the switch 601 even if there is a loss of power to the actuator 651.

In another embodiment, electrical power to the actuator 651 is also the control signal. The opto-mechanical switch 601 may have a normal position that the center member assumes when power to the actuator 651 is disconnected. Because the switch 601 may only be actuated periodically, energy may be saved because the actuator 651 does not continuously consume electricity. The switch 601 may be configured to be either "normally on" or "normally off." In the "normally off switch configuration the "off switch fibers are normally aligned with the input and output fibers and the actuator 651 is only energized when the switch 601 is actuated into the "on" position. Alternatively, in the normally on configuration, the "on" switch fibers are normally aligned with the input and output fibers and the actuator 651 is only energized when the switch 601 is actuated into the off position.

With reference to Figure 7, the actuator 751 and the opto-mechanical switch 701 may be mounted in a package 761. The package 761 provides a support frame for the actuator 751, blocks 763 and the center member 719. The input fibers 703, 705 and the output fibers 713, 715 may each be mounted in blocks 763 and ends of the input fibers 703, 705 and output fibers 713, 715 may abut planar surfaces of the blocks 763. The package 761 may be configured to be easily connected to other packages 761 containing other optical signal control elements. The actuator 751 and/or the opto-mechanical switch 701 may be independently removed from the package 761 for repair, replacement or modification without having to disassemble other components of the switch assembly or other packages in the modular system. Packages 761 are easily mounted on a board and allow any other optical devices mounted in packages 761 to be easily interconnected as modules of an optical system. The package system may be used with any of the disclosed switch embodiments or optical components.

In an embodiment, the center member 719 of the switch 701 may have a cross shape that supports the ends of the switch fibers. The switch fibers abut polished planar side surfaces of the center member 719. The center of the center member 719 may be hollow and the center portions of the switch fibers may not be supported by the center member 719. The planar sides of the center member 719 may slide against the planar surfaces of the blocks 763. In an embodiment, the actuator 751 may be connected to the center member

719 of the opto-mechanical switch 701 with an actuator arm 751 which may engage the ends of the cross shaped center member 719. The actuator 753 may move the actuator arm 753 vertically in response to a control signal between the "on" and "off positions. In an embodiment, the actuator 753 precisely aligns the selected switch fibers in the center member 719 with the input fibers 703, 705 and output fibers 713, 715 in the blocks 763. In alternative embodiments, a mechanism provides upper and lower stops that limit travel of the center member 719 and aligns the switch fibers with the input fibers 703, 705 and output fibers 713, 715 in the "on" and "off positions. The transmitted signal strength may be reduced by gaps between the aligned input fibers, switch fibers and output fibers. The gaps between the adjoining fibers may be minimized by compressing the blocks 763 containing the input fibers 703, 705 and output fibers 713, 715 against the center member 719. In an embodiment, springs may be used to compress the blocks 763 against the center member 719. In other embodiments, any other force mechanism may be used to compress the blocks against the center member including: magnetic, fluid pressure, vacuum, gravity, force transducers or any other suitable mechanical device.

The compression of the center member may compensate for irregularities in the sliding surfaces of the opto-mechanical switch. For example, if the surfaces of the switch are not perfectly flat, the compression may compensate for some dimensional irregularities. Similarly, the compression can compensate for variations in dimensional tolerances, manufacturing irregularities and thermal expansion. The compression force should not create a significant amount of friction between the sliding components of the optical switch. With proper alignment of the optical elements and a minimal gap between the optical elements, the signal losses through the inventive wavelength switch may be less than 0.1 dB.

In order to minimize signal losses through the wavelength switch, it is desirable to have the adjoining ends of optical fibers or other optical elements highly polished and placed as close together as possible. Reflective signal losses may be minimized by slant polishing the ends of the optical fibers to approximately 8°. In an embodiment, the ends of the optical switch fibers may be slant polished flush with the sides of the center member. Similarly, the input fibers and output fibers may be slant polished after securing the optical elements to fixed switch components. The exposed ends of the optical elements and the planar surfaces may be polished simultaneously. In an embodiment, the optical elements may be fastened to the center member and blocks and the sliding planar surfaces may be subsequently polished together.

Other signal losses are primarily the result of random scattering of light and absorption of the light by impurities within the glass fibers. Another source of loss within the fiber is due to excessive bending, which causes some of the light to leave the core area of the fiber. Smaller bend radii produce greater signal losses in the optical fibers. The bending of the switch fibers within the center member may have a turning radius of at least an 20 mm. Figure 8 illustrates a more detailed view of an embodiment of the optomechanical switch 801. The opto-mechanical switch 801 may include V-groove blocks which have uniformly spaced grooves across a surface and are well known in the optical fiber art. The input fibers 803, 805 and output fibers 813, 815 may be mounted in V-grooves and secured to the blocks 863 with covers 893. The switch fibers 821, 823, 825, 827 may be mounted in V-groove in the center member 819 and similarly secured to the center member 819 with covers 893. The covers 893 may be secured to the V-groove of the blocks 863 and center member 819 with screws, adhesives or any other suitable fastening device. The blocks 863 are mounted around the center member 819. The V-groove blocks may be metal, plastic, ceramic, glass or any other suitable material.

The optical fibers may have a cover coating that helps to protect the glass fiber. The cover coating may be of a polyamide material or any other suitable material. The cover coating may be stripped at sections so that only the bare glass fiber engages the V-groves. The diameter of the coated fiber may be about 250 μm and the diameter of the bare glass fiber may be about 125 μm.

In an embodiment, the opto-mechanical switch 801 may also include alignment rods 891 and grooves 831 which provide stops for aligning the optical fibers. Two alignment rods 891 may be mounted in each of the blocks 863 on opposite sides of the input fibers 803, 805 and output fibers 813, 815. A portion of the alignment rods 891 extending from the blocks 863 may engage the grooves 831 in the center member 819. The ends of the grooves 831 may correspond with alignment positions of the optical fibers. When the center member is in the "off position, the "off switch fibers 821, 823 are aligned with the input fibers 803, 805 and the output fibers 813, 815, and the rods 891 are in contact with the upper end of the grooves 831. Similarly, when the rods 891 contact the lower end of the grooves 831, the "on" switch fibers 825, 827 are aligned with the input fibers 803, 805 and the output fibers 813, 815. Precise positioning of the center member 819 by the actuator is not required with the optical switch 801 having an alignment mechanism. The actuator only needs to move the center member 819 against the alignment stops to align either the "off switch fibers 821, 823 or the "on" switch fibers 825, 827 with the input fibers 803, 805 and the output fibers 813, 815.

In an embodiment, the optical fibers and the alignment rods 891 of the switch 801 may be mounted in V-groove blocks. The rods 891 may engage slots 831 in the center member 819 which limit the travel of the center member 819 between blocks 863. The slots 831 may be formed in the center member 819 by removing material between adjacent grooves and placing a cover 863 over the enlarged grooves. In an alternative embodiment, the rods 891 may be mounted in the center member 819 and may engage slots in the surrounding blocks 863. Figure 9 illustrates the center member 919 in more detail. The center member

919 may include two cross pieces 929 be fastened to each other to form a cross shaped assembly. The cross pieces 929 may have cut out centers andN-groove blocks on the ends. The cuts outs may reduce the mass of the center member 919 and allow the switch to actuate more quickly and with less actuator energy. The ends of the switch fibers 921, 923, 925, 927 may be placed in grooves at the ends of the cross pieces 929 and held in place with covers 993. The ends of the off switch fibers 921, 923 may be mounted in grooves above the groves that the on switch fibers 925, 927 are mounted in so that when the center member 929 turns the switch off when the center member 929 is in a lower position.

In alternative embodiments, the blocks and the center member may be made of molded components. The holes and slots in the blocks and center member may also be molded or machined into the components. The optical fibers and the rods may be molded into the blocks or inserted into holes in the molded blocks. If the rods and optical fibers are molded into the switch components, they are inherently secured within the blocks and center member. If the rods and optical fibers are inserted into holes in the blocks an adhesive or any other suitable fastening process, material or device may be used to secure the rods and optical elements within the blocks or center member. Again the alignment rods engage slots which limit the travel of the center block between the input and output fiber blocks and provide alignment stops for the switch fibers between the input and output fibers.

Referring to Figure 10, an embodiment of a switch matrix 1001 is illustrated. Each of the switches 1061, 1063 may be oriented with inputs at the top and left sides and the outputs at the bottom and rights sides. Thus, by connecting many switches 1061, 1063 in the same orientation, the output sides of switches 1061, 1063 will face the input sides of adjacent switches 1061, 1063 to the right and bottom. As discussed, "off position switches 1063 allow signals to pass straight across the switch 1063 and "on" position switches 1061 divert the signals 90 degrees. The sequential letters adjacent to the inputs of the array of switches 1001 correspond with the numbers and letters adjacent each of the outputs and indicate the paths of each of the signals through the array of switches 1001. By controlling the positions of the individual switches 1061, 1063 in the array of switches 1001, the paths of the signals travelling through the array of switches 1001 can be controlled. A signal from any one of the inputs may be directed to any one of the outputs.

In an alternate embodiment, the array of switches 1001 may be used with demuxing and muxing devices. Input signals may travel through a single optical fiber to demuxing devices and the individual demuxed signals may be transmitted to the array of switches 1001. The individual signals may then be directed through the array of switches 1001 to any one of the outputs and transmitted to a muxing device. In this embodiment a control system must coordinate the paths of the signals through the array of switches 1001 to insure that two signals having the same frequency are not directed to the same output muxing device and transmitted to the same output optical fiber. As discussed, the signal losses through the inventive opto-mechanical switch may be less than 0.1 db. In a 8x8 array of switches the signals may pass through up to 15 different switches and thus the signal loss for a signal traveling through the switch array will be less than 1.5 dB (15 x 0.1 dB).

With reference to Figure 11, a cut away view of compliant ferrule connector 1101 is illustrated. The compliant ferrule connector 1101 includes an optical fiber 1121 and a surrounding cover 1195 mounted between two ferrules 1193. The optical fiber 1121 may be mounted concentrically within the ferrules 1193 may be tube shaped structures that are fastened to the ends of the cover 1195. The ends of the internal optical fiber 1121 may be flush with the ends of the ferrules 1193. The cover 1195 may be a polyamide or any other type of flexible material which enables compliant ferrule connector 1101 to bend, expand or contract. In an embodiment, the compliant ferrule connector 1101 may be approximately 2 mm in length and 250 μm in diameter. The compliant ferrule connector 1101 may be able to deflect off axis up to approximately 50 μm or more and expand or contract up to approximately 50 μm. The flexibility of the compliant ferrule connector 1101 may be proportional to the length, thus longer compliant ferrule connectors 1101 may be able to deflect and expand or contract much more than 50 μm.

The compliant ferrule connector 1101 structure may be used with all optical components of the described opto-mechanical switch embodiments. Specifically, the ferrules 1193 of the compliant ferrule connector 1101 may be mounted in the N- groove blocks of the input blocks, output blocks, and center member of the described switch devices.

The compliant ferrule connector 1101 may also be easily connected to other optical components with N-groove blocks. As discussed, the optical fibers 1121 are mounted in circular cross section ferrules 1193. Thus two optical fibers mounted within ferrules 1193 are aligned and connected when placed in a common N-groove with their end ferrules 1193 butted up against each other. By securing the ferrules 1193 against each other in a N-groove, the optical fibers are connected with very little signal loss.

The compliant ferrule connectors 1201 may also be used as to connect adjacent optical devices. In Figure 12, a group of packages 1261 that are interconnected with compliant ferrule connectors 1201 is illustrated. The flexibility of the compliant ferrule connectors 1201 allows interconnection where the packages 1261 are not precisely aligned or where there may be some movement between the packages 1261. The compliant ferrule connectors 1201 also allow for some irregularities in the positioning of the packages 1261 on a mounting board. The packages 1261 may have sockets that are releasably connectable to the compliant ferrule connectors 1201. In an embodiment, the sockets may have a N-groove block similar to that previously described with reference to Figure 9. By securing the compliant ferrule connector 1201 within the N-groove of the socket, the optical fiber within the compliant ferrule connector 1201 is aligned with optical components in the packages 1261. The compliant ferrule connector 1201 may be secured within socket of the package 1261 with a cover or any other fastening mechanism.

Figure 13 illustrates a modular embodiment of the opto-mechanical switch 1301 that is easily connected to other switches 1301. In this embodiment, the switch 1301 includes compliant ferrule connectors 1303 which extends from the switch 1301 and sockets 1313 which may be releasably connected to the compliant ferrule connectors 1303. Adjacent opto-mechanical switches 1301 are easily connectable by placing the compliant ferrule connectors 1303 of an opto-mechanical switch 1301 into the sockets 1313 of an adjacent opto-mechanical switches 1301. As discussed, the sockets 1313 may include N-grooves which assists in aligning the optical fibers 1303 with other optical components within the switches 1301. The opto-mechanical switches 1301 may be 5 mm x 5 mm or smaller in size.

In an alternative embodiment, the compliant ferrule connector structure described with reference to Figure 11 is used with multiple groove N-groove blocks to form an optical switch mechanism. Figures 14A and 14B are detailed illustrations of an input block 1409 portion of an embodiment of an optical switch mechanism which includes an input fiber assembly 1405, an "off switch fiber assembly 1421, and an "on" switch fiber assembly 1427. Ferrules 1493 are mounted on the ends of the assemblies and covers protect the internal optical fibers. The "off switch fiber assembly 1421 and the "on" switch fiber assembly 1427 are placed in adjacent grooves of the input block 1409. The input fiber assembly 1405 is secured in the center groove of the input block 1409 and either the "off switch fiber assembly 1421 or the "on" switch fiber assembly 1427 are aligned with the input fiber assembly 1405 depending upon the position of the switch. As discussed, when the ferrules 1493 are placed in very close proximity with each other in a N-groove, the optical fibers are connected with very little signal loss.

As discussed, ferrules 1493 are mounted on the ends of the optical element assemblies. The ferrules 1493 protect the optical elements of the "off switch fiber assembly 1421 and the "on" switch fiber assembly 1427 from damage due to rolling or sliding between grooves in the N-groove input block 1409. The input N-groove block 1409 may be ceramic, plastic, metal or any other suitable material.

In an embodiment, all input and output blocks of an opto-mechanical switch may be configured with the described N-groove block mechanism. As discussed above regarding the "off position, the "off switch fiber assemblies are aligned with the input and output optical fibers and in the "on" position, the "on" switch fiber assemblies are aligned with the input and output optical fibers. In an other embodiment, an actuator may be used to move either the "off switch fiber assemblies or the "on" switch fiber assemblies into alignment with the input and output fibers in response to a control signal. Figures 15A and 15B illustrate a cross section view of an embodiment of the input block 1509 of an opto-mechanical switch. A switch V-groove block 1587 having two grooves is used to slide the "off fiber assembly 1521 and the "on" fiber assembly 1527 between grooves in the input V-groove block 1509. In this embodiment, the "off fiber assembly 1521 and the "on" fiber assembly 1527 may roll between the adjacent grooves of the input V-groove block 1509 and slide against the surfaces of the grooves of the switch V-groove block 1587. The contact points between the ferrules 1593 and the switch V-groove block 1587 may have a low coefficient of friction so that the sliding friction is minimal. Figure 15A illustrates the opto-mechanical switch in the off position with the "off fiber assembly 1521 placed in the center groove of the input block 1509 and Figure 15B illustrates the optomechanical switch in the "on" fiber assembly 1527 placed in the center groove. The described switch V-groove block mechanism may be used for all input and output blocks and an actuator (not shown) may be attached to all switch V-groove blocks of an opto-mechanical switch. As discussed above, the actuator aligns either the "off fiber assemblies or the "on" fiber assemblies with the input and output fibers in response to a control signal.

Figures 16A and 16B illustrate a cross section view of another embodiment of the input block 1609 of the opto-mechanical switch. In this embodiment, an switch V-groove block 1685 has three grooves which roll the "off switch fiber assembly 1621 and the "on" switch fiber assembly 1627 between grooves in the input V-groove block 1609. In this embodiment, the "off switch fiber assembly 1621 and the "on" switch fiber assembly 1627 may roll across grooves in the input V-groove block 1609. Again, the V-groove switch mechanism may be used for all input and output blocks of an opto-mechanical switch. An actuator (not shown) may be attached to the switch V-groove blocks to align either the "off switch fiber assemblies or the "on" switch fiber assemblies between the input and output fibers in response to a control signal. Figure 17 illustrates an embodiment of the optical switch 1701 which incorporates the input blocks illustrated in either Figures 15A and 15B or Figures 16A and 16B. Four blocks 1763 are mounted around the center member 1719. The center member 1719 holds the "off switch fibers 1723 and "on" switch fibers 1725 and moves vertically to actuate the switch 1701 between the "on" and "off positions. As discussed with reference to Figures 15A, 15B, 16A and 16B, the ends of the optical fibers of the switch 1701 are mounted in ferrules (not shown) and the ends of the center member 1719 and blocks 1763 have parallel grooves. The center member 1719 and blocks 1763 align either the "off switch fibers 1721, 1723 or the "on" switch fibers 1725, 1727 with the input fibers 1703, 1705 and output fibers 1713, 1715 which are held stationary in a center groove of the blocks 1763. In another embodiment illustrated in Figure 18, the opto-mechanical switches may be used with muxing devices 1893, 1895 and demuxing devices 1881, 1883 to form an add/drop optical system 1801. The add/drop system 1801 includes an input fiber 1803, an output fiber 1813, an add fiber 1823 and a drop fiber 1833. Muxed input signals travel through the input fiber 1803 to the input demuxing device 1881 and muxed add signals travel through the add fiber 1823 to the add demuxing device 1883. The demuxing devices 1881, 1883 separate the individual input and add signals which are then transmitted through individual fibers to either "on" switches 1861 or "off switches 1863. The input signals that pass through the "off switches 1863 are directed to the output muxing device 1893 and add signals that pass through the "off switches 1863 are directed to the drop muxing device 1895. Input signals that pass through the "on" switches 1861 are directed to the drop muxing device 1895 and add signals that pass through the on switches 1861 are directed to the output muxing device 1893. The input signals and the add signals that have the same frequency may be directed to the same switch so that two signals having the same frequency signals can not both be directed to the same muxing device 1893, 1895. Signals exiting the output muxing device 1893 are transmitted through the output fiber 1813 and signals exiting the drop muxing device 1895 are transmitted through the drop fiber 1833. In the foregoing, an opto-mechanical switch for fiber optic communications networks is described. In all of the disclosed embodiments, the opto-mechanical switches may be toggled by actuators in response to a control signal. The switch assemblies may include rods which engage slots to provide alignment stops for the optical fibers. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Claims

What is claimed is: 1. An opto-mechanical switch, comprising: a center member containing a first switch fiber, a second switch fiber, a third switch fiber and a fourth switch fiber; a first input fiber; a second input fiber; a first output fiber; a second output fiber; wherein the center member is movable between a first position and a second position, in the center member's first position, the first switch fiber is aligned between the first input fiber and the first output fiber and the second switch fiber is aligned between the second input fiber and the second output fiber, and in the center member's second position the third switch fiber is aligned between the first input fiber and the second output fiber and the fourth switch fiber is aligned between the second input fiber and the first output fiber.

2. The opto-mechanical switch of claim 1 further comprising: an actuator for moving the center member between the first position and the second position in response to a control signal.

3. The opto-mechanical switch of claim 2 further comprising: an automatic latch mechanism that locks the center member into its last position in the event of a power outage to the actuator or a malfunction of the actuator.

4. . The opto-mechanical switch of claim 1, wherein the center member has four side surfaces and the first switch fiber and the second switch fiber intersect two opposing side surfaces of the center member and the first optical fiber is substantially perpendicular to the second optical fiber.

5. The opto-mechanical switch of claim 4, wherein the third switch fiber intersects two substantially perpendicular side surfaces of the center member and the fourth switch fiber intersects two substantially perpendicular side surfaces of the center member that are opposite to those intersected by the third switch fiber.

6. The opto-mechanical switch of claim 1, wherein the first switch fiber and the second switch fiber intersect side surfaces of the center member at a first group of points that define a first plane; and the third switch fiber and the fourth switch fiber intersect side surfaces of the center member at a second group of points that define a second plane.

7. The opto-mechanical switch of claim 1 further comprising: one or more rods which engage the center member and limit the travel of the center block relative to the first input fiber, the second input fiber, the first output fiber and the second output fiber.

8. An opto-mechanical switch system comprising: a plurality of opto-mechanical switches of claim 2; wherein the first output fiber of a first opto-mechanical switch is connected to the first input fiber of a second opto-mechanical switch and the second output fiber of a first opto-mechanical switch is connected to the input fiber of a second input fiber of a third opto-mechanical switch.

9. An opto-mechanical switch, comprising: a center member containing a first switch fiber, a second switch fiber, a third switch fiber and a fourth switch fiber movable between a first position and a second position; a first input fiber mounted in a first input block; a second input fiber mounted in a second input block; a first output fiber mounted in a first output block; a second output fiber mounted in a second output block; wherein when the center member is in the first position, the first switch fiber is aligned with the first input fiber and the first output fiber and the second . switch fiber is aligned with the second input fiber and the second output fiber, and when the center member is in the second position, the third switch fiber is aligned with the first input fiber and the second output fiber and the fourth switch fiber is aligned with the second input fiber and the first output fiber.

10. The opto-mechanical switch of claim 9 further comprising: an actuator for moving the center member to the first position or the second position in response to a control signal.

11. The opto-mechanical switch of claim 10 further comprising: an automatic latch mechanism that locks the center member into its last position in the event of a power outage to the actuator or a malfunction of the actuator.

12. The opto-mechanical switch of claim 9, wherein the center member has four side surfaces and the first switch fiber and the second switch fiber intersect two opposing side surfaces of the center member and the first switch fiber is substantially perpendicular to the second switch fiber.

13. The opto-mechanical switch of claim 9, wherein the first switch fiber and the second switch fiber intersect side surfaces of the center member at a first group of points that define a first plane; and the third switch fiber and the fourth switch fiber intersect side surfaces of the center member at a second group of points that define a second plane.

14. The opto-mechanical switch of claim 9, wherein the first input block, the second input block, the first output block and the second output block are compressed against the center member.

15. The opto-mechanical switch of claim 14, wherein springs are used to compress the first input block, the second input block, the first output block and the second output block against the center member.

16. The opto-mechanical switch of claim 9 further comprising: one or more rods engage the center member and limit the travel of the center block relative to the first input fiber, the second input fiber, the first output fiber and the second output fiber.

17. An opto-mechanical switch system comprising: a plurality of opto-mechanical switches of claim 9; wherein a first output fiber of a first opto-mechanical switch is connected to a first input fiber of a second opto-mechanical switch and a second output fiber of the first opto-mechanical switch is connected to a second input fiber of a third opto-mechanical switch.

18. An opto-mechanical switch system having: a plurality of switches each comprising: a center member, a first switch fiber, a second switch fiber, a third switch fiber, a fourth switch fiber, a first input fiber, a second input fiber, a first output fiber, a second output fiber, and an actuator that moves the center member between a first position and a second position, wherein when the center member is in the first position, the first switch fiber is aligned with the first input fiber and the first output fiber and the second switch fiber is aligned with the second input fiber and the second output fiber, and when the center member is in the second position the third switch fiber is aligned with the first input fiber and the second output fiber and the fourth switch fiber is aligned with the second input fiber and the first output fiber; a first demuxing device connected to the first input fiber of the plurality of switches; a second demuxing device connected to the second input fiber of the plurality of switches; a first muxing device connected to the first output fiber of the plurality of switches; and a second muxing device connected to the second output fiber of the plurality of switches.

19. The opto-mechanical switch system of claim 18 wherein each of the plurality of switches further comprises: one or more rods which engage the center member and limit the travel of the center block relative to the first input fiber, the second input fiber, the first fiber block and the second output fiber.

20. The opto-mechanical switch system of claim 18 wherein in each of the plurality of switches the first switch fiber and the second switch fiber intersect side surfaces of the center member at a first group of points that define a first plane; and the third switch fiber and the fourth switch fiber intersect side surfaces of the center member at a second group of points that define a second plane that is substantially parallel to the first plane.

21. The opto-mechanical switch system of claim 18 wherein for each of the plurality of switches: the first input fiber is mounted in a first input block, the second input fiber is mounted in a second input block, the first output fiber is mounted in a first output block and the second output fiber is mounted in a second output block.

22. The opto-mechanical switch system of claim 21 wherein, the first input block, the second input block, the first output block and the second output block are compressed against the switch member.

23. An opto-mechanical switch, comprising: a first input block having a plurality of grooves, wherein a first input fiber is mounted in a center groove of the first input block; a first output block having a plurality of grooves, wherein the first output fiber is mounted in a center groove of the first output block; a second output block having a plurality of grooves, wherein the second output fiber is mounted in a center groove of the second output block; an off switch fiber; and an on switch fiber; wherein when the opto-mechanical switch is in an off position, a first end of the off switch fiber is placed in the center groove of the first input block in alignment with the first input fiber and a second end of the off switch fiber is placed in the center groove of the first output block in alignment with the first output fiber; and wherein when the opto-mechanical switch is an on position, a first end of the on switch fiber is placed in the center groove of the first input block in alignment with the first input fiber and a second end of the on switch fiber is placed in the center groove of the second output block in alignment with the second output fiber.

24. The opto-mechanical switch of claim 23 wherein ferrules are mounted on the ends of the on switch optical fiber and the ends of the off switch optical fiber.

25. The opto-mechanical switch of claim 23 further comprising: an actuator; wherein the actuator moves either the off switch fiber or the on switch fiber into alignment with the input fiber in response to a control signal.

26. The opto-mechanical switch of claim 24 further comprising: an switch block having at least two grooves wherein the switch block is in contact with the off optical fiber and the on optical fiber and the actuator moves the switch block in response to a control signal.