Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     The present application relates and claims priority to U.S. Provisional Application Ser. No. 62/134,298, filed Mar. 17, 2015, the entirety of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates generally to] optical switches and more particularly toward an improved mechanical switch for selectively coupling light from two input fibers to a selected two of a plurality of output optical fibers. 
     BACKGROUND 
     In order to realize the potential of fiber optic transmission of light signals, some form of switching mechanism must be provided for moving light signals from one fiber to another. In principle, mechanical switches have a number of advantages over other forms of optical switches for applications in which switching speed is not important. Mechanical switches offer low insertion losses, a high degree of immunity against backscattering of light from the switch back down the input fiber, low cross-talk, and insensitivity to the wavelength of the light being switched. 
     Prior mechanical switches, however, have been too costly to achieve full market acceptance. Typically, these switches operate by moving an input fiber relative to a plurality of output fibers. The simplest schemes utilize a “butt-coupling” scheme in which the input fiber is aligned with one of a plurality of output fibers using a motor. The output fibers are usually fixed to a carrier and have ends cut at an angle to prevent reflections from the ends generating reflections that propagate back down the input fiber. The angle is typically 6 to 10 degrees. 
     To provide acceptable insertion losses, the ends of the fiber in a butt-couple switch must be separated by an extremely small distance. This tolerance is difficult to achieve in switches having a large number of output fibers. Hence, butt-coupling schemes, while appearing simple, are in reality extremely difficult and challenging to implement in large fan-out switches. 
     Accordingly, there is a long-felt yet unsolved need in the art for a mechanical switch that selectively couples light from two input fibers to a selected two of a plurality of output optical fibers, without using lenses or beam collimators. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to inventive fiber optic switches. Embodiments of the invention fiber optic switches described or otherwise envisioned herein include a switch for selectively coupling light from two input fibers to a selected two of a plurality of available output optical fibers. The switch is able to use standard fiber optical connectors which meet the specifications for optical performance. The duplex mechanical switch creates a method to physically switch two fibers (duplex) to another two fibers (duplex). With the improved fiber optic switches, it is possible to move light signals from one fiber to another with low insertion losses, a high degree of immunity against backscattering of light from the switch back down the input fiber, low cross-talk, and insensitivity to the wavelength of the light being switched. 
     According to an aspect, a fiber optic switch device includes: (i) a plurality of output optical fibers, each having an output fiber first end; (ii) a slider assembly moveable between a first position and a second position, the slider assembly comprising a first input fiber and a second input fiber, each having an input fiber first end, and a first pin and second pin each extending outwardly; (iii) a program plate defining a first channel and a second channel, into which the first pin and second pin, respectively, are inserted, wherein the pins are moveable within the channel from the first position to the second position; (iv) wherein in the first position, the first ends of the first and second input fibers are aligned and in light-transmissive communication with the output fiber first end of a first two of the plurality of output optical fibers; and (v) wherein in the second position, the first ends of the first and second input fibers are aligned and in light-transmissive communication with the output fiber first end of a second two of the plurality of output optical fibers. 
     These and other aspects and embodiments of the invention will be described in greater detail below, and can be further derived from reference to the specification and figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which: 
         FIG. 1A  is a schematic of a duplex mechanical fiber switch (“DMFS”) in a first position in accordance with an embodiment. 
         FIG. 1B  is a schematic of a duplex mechanical fiber switch (“DMFS”) in a second position in accordance with an embodiment. 
         FIG. 2  is an exploded view of a fiber switch (“MFS”) assembly layout in accordance with an embodiment. 
         FIG. 3  is an exploded view of the slider assembly of an MFS in accordance with an embodiment. 
         FIG. 4  is a table illustrating the performance of existing hybrid switches compared to the DMFS. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in  FIG. 1A  a schematic of a DMFS  10  in a first position. The DMFS  10  has a slider assembly  12  consisting of S 1   14  and S 1 A  16 . Slider assembly  12  is shown in position “A,” which connects the slider to pins  18  and  20  on the Quad Bulkhead  22 . When the slider assembly  12  moves to position “B,” as shown in  FIG. 1B , the slider assembly connects to pins  24  and  26  on the Quad bulkhead  22 . The configuration illustrated is a 2×2 Mechanical switch (duplex). 
     Referring now to  FIG. 2  is an exploded view of the components of a DMFS  10 . The DMFS  10  comprises a Quad MFS Housing Bottom  28 . Quad housing bottom  28  contains the Quad Bulkhead  22  and the Steel Flat Head Screws  30  beneath the Quad Bulkhead  22 . The slider assembly  12  provides the physical movement in the X and Y directions. Slider assembly  12  contains two LC/APC connectors which are used to provide the mating in the two positions. A stainless bar  32  is used to move the slider assembly  12  in the X or Y direction. There are two pins  34  on top of the slider, as shown in  FIG. 3 , which are used with the program plate  36  above, to insure the direction of travel when the knob and shaft  38  is turned. The front of the bottom  40  of the slider  12 , as shown in  FIG. 3 , has two magnets  42  beneath each connector which are used to “snap” the connectors into the Quad Bulkhead  22  where the steel flat head screws  30  are located below in  FIG. 2 . The two magnets  42  also provide stability and consistency to the ferrules. The double cam assembly  44  provides a unique movement for the slider  12  in the X and Y direction via the Program Plate  36 . The Quad DMS Housing Top  46  has all of the screws  48  to secure the module. 
     Referring now to  FIG. 3  is an exploded view of the components for the slider assembly  12 . It can comprise, for example, a bottom housing  40  which contains the stainless steel bar  32  along with the two magnets  42 . The Connector Retainer Clip  50  holds the two connectors in place. It is important to note that the connector retainer clip  50  also provides added flexibility for the connector housings when inserting into the mating bulkhead. In order to maintain consistency, regarding losses of light, the connector housings are isolated in order to keep the ferrules mating tension consistent when the magnetic field is sensed. The two set screws  52  are used to stabilize the connector housings. The two dowel pins  34  are used to position the slider assembly  12  based on the program plate  36  shown in  FIG. 2 . The top plate  46  is used to secure to the bottom housing  40  with the three screws  48 . The top plate  46  also holds the dowel pins  34  and the connector adjusting screws  52 . 
     Referring now to  FIG. 4  is a performance table illustrating various parameters including as Loss, back reflection, crosstalk and fiber type. The “Existing” column contains information about typical measurements of all of the parameters of existing switches on the market. The “MFS” Mechanical Fiber Switch column is measurements using the DMFS. The measurement results are significant because the MFS is a “true mechanical fiber switch” which uses standard mating connectors and mating bulkheads. Some of the advantages of the MFS consist of manual switching without any external power. Low loss based on ferrule to ferrule contact which are using the magnets to provide a consistent balance and attraction for the ferrules. Repetitive connections are also consistent when the loss is measured because of the added magnet attraction for stability. Various types of fiber can be used such as single mode, multi-mode, along with the added specialty fiber on the market. The crosstalk continues to be very high because of the isolation of the connectors. 
     According to one embodiment, it is eliminating stainless steel bar  32  from the slider assembly  12 . For example, according to an embodiment the Program plate  36  in  FIG. 2  can be modified to incorporate an additional pin guide. The added pin on the slider makes a total of three pins in a triangle configuration and can be used to navigate the slider assembly  12  without the stainless steel bar  32 . The pin, which is on the top center of the slider assembly  12 , is connected to the double Cam assembly  44  which is considered to be the “Driver Pin.” The two pins that are directly behind the “Driver” are called the “Steering Pins,” which are used to guide the slider  12  in the various directions like a wheel barrel. For example, according to an embodiment, the Program plate  36  or board can comprise three horseshoes which control the slider. This slider  12  has three dowel pins on the top plate instead of two. The three pins work with the program board  36  and follow the triple horse shoe pattern. This provides a more consistent movement for the slider  12  because it is like a wheel barrel and the single pin is the wheel and the other two pins are the handles for the wheel barrel for steering. 
     Although the present invention has been described in connection with a preferred embodiment, it should be understood that modifications, alterations, and additions can be made to the invention without departing from the scope of the invention as defined by the claims.

Technology Category: 3