Abstract:
A non-intrusive monitoring optical connection apparatus includes first and second fiber optic communication lines ( 2, 8 ) arranged for light to pass therebetween. The first and second fiber optic communication lines ( 2, 8 ) have first and second ferrules ( 4, 6 ) at ends thereof, respectively. An optical element ( 13, 25 ) is disposed between the fiber optic communication lines ( 2, 8 ). Most of the light passes between the fiber optic communication lines ( 2, 8 ) and a small part of the light is harvested by the optical element ( 13, 25 ) and detected by a photo detector ( 15, 28 ).

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to non-intrusive monitoring of light signals between two fiber optic communication lines. 
     BACKGROUND OF THE INVENTION 
     There are many optical connections used in fiber optics, such as in distribution frames, patch panels, fiber optic adapters and termination devices. Such systems often require non-intrusive monitoring of light signals between two fiber optic communication lines. However, these systems do not offer cost effective solutions for non-intrusive monitoring. Prior art solutions for monitoring an active line include disconnecting and attaching a monitor device to each of the ends of the fiber optic lines. 
     Another solution utilizes a splitter which requires expensive tooling and extra spacing with an additional box. (See PCT patent application PCT/US2010/025293, “Fiber Optic Cross Connect with Non-Intrusive Monitoring and Circuit Tracer”, to Benny Gaber). 
     SUMMARY 
     The present invention seeks to provide methods and apparatus for non-intrusive monitoring of light signals between two fiber-optic communication lines, such as but not limited to, distribution frames, patch panels, fiber optic adapters and termination devices. 
     In one embodiment of the invention, an optical element is disposed between two fiber optic communication lines. Most of the light from the transmitting fiber is received at the receiving fiber, whereas the optical element harvests only a small part of the light signals, thus achieving efficient non-intrusive monitoring without interrupting the ongoing transmission of optical information data in both directions between the two fiber optic communication lines. The harvested light from the optical element is directed onto a photo detector or a light guide attached to the optical element. If necessary, the light guide may optionally have an infrared (IR) coating that serves to change the wavelength from IR into visible light. 
     In accordance with an embodiment of the present invention, the optical element is a side-emitting ferrule. For example, the ferrule may have an optical opening in its cladding, perpendicular to its axial axis, allowing harvesting part of the light energy in the cladding which is emitted through the opening. The harvested light is detected by at least one photo detector attached to the opening on the ferrule side, again without interrupting the transmission of optical information data. The partially optical opening in its cladding could be on a ferrule of the fiber optic line itself. The at least one photo detector on the opening in the cladding may consist of a plurality of photo detectors. The photo detector or detectors may be of narrow band wavelength. The photo detecting system allows for remote monitoring. 
     In yet another embodiment of the present invention a non-intrusive monitoring device in a fiber optic connection is provided wherein the optical element is a ferrule size lens set including first and second discs and a cylinder with a density filter and a collimating lens shape on both ends of the cylinder. A first fiber optic communication line ferrule is attached to the first disc. Light exiting the first fiber optic communication line ferrule, in its numerical aperture angle, is collimated at the first end collimated lens shape of the cylinder. The light beam travels as a large collimated beam in the density filter cylinder and exits at the second collimated lens face, where it is concentrated into a second fiber optic communication line. The cylinder includes on its side face, perpendicular to its axial axis, at least one photo-detector. This allows for part of the light in the collimated beam in the cylinder to be dispersed, reflected and detected by the photo-detector. 
     In another embodiment of the present invention, which utilizes the ferrule size optical element, the cylinder is fully transparent and has a notch on its side face, opposite the photo-detector, thereby reflecting part of the collimated beam that may come from each direction onto the photo-detector. 
     In another embodiment of the present invention, which utilizes the ferrule size optical element, a light guide is attached to the cylinder instead of the photo-detector. In another embodiment of the present invention, which utilizes the ferrule size optical element, a light guide is attached to the cylinder and is coated with IR coating changing the wavelength from IR into visible light, allowing monitoring without interrupting the ongoing transmission of optical information data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: 
         FIG. 1  is a simplified general view illustration of a non-intrusive monitoring system with optical element ferrule and photo detector, in accordance with an embodiment of the present invention. 
         FIG. 2.1  is a simplified side translucent view illustration of a non-intrusive monitoring system with an optical element ferrule and photo detector. 
         FIG. 2.2  is a simplified cutaway view illustration of an optical element ferrule with photo detector. 
         FIG. 3.1  is a simplified enlarged view illustration of an optical element ferrule with photo detector. 
         FIG. 3.2  is a simplified general view illustration of an optical ferrule cut. 
         FIG. 4  is a simplified general view illustration of a non-intrusive monitoring system with the photo detector on the ferrule line end. 
         FIG. 5.1  is a simplified isometric cutaway view illustration of a photo detector on the ferrule line end. 
         FIG. 5.2  is a simplified cutaway view illustration of a photo detector on the ferrule line end. 
         FIG. 5.3  is a simplified enlarged view illustration of a photo detector on the ferrule line end. 
         FIG. 6.1  is a simplified general view illustration of a photo detector on the ferrule line end. 
         FIG. 6.2  is a simplified general view illustration of a cut in the ferrule line end. 
         FIG. 7  is a simplified general view illustration of two photo detectors on the ferrule line end. 
         FIG. 8.1  is a simplified front cutaway view illustration of a non-intrusive monitor system where the optical element is a ferrule with a side opening. 
         FIG. 8.2  is a simplified front cutaway view illustration of a non-intrusive monitor system where the optical element is a ferrule with a side opening and an IR coated light guide. 
         FIG. 9.1  is a simplified cutaway view illustration of a non-intrusive monitor system where the optical element is a set of two discs and a cylinder with density filter and collimated faces, and including a photo detector. 
         FIG. 9.2  is a simplified cutaway view illustration of a non-intrusive monitor system where the optical element is a set of two discs and a cylinder with density filter and collimated faces and photo detector, showing the light path. 
         FIG. 9.3  is a simplified side cutaway view illustration of a non-intrusive monitor system where the optical element is a set of two discs and a cylinder with density filter and collimated faces and photo detector, showing the dispersed light reflected onto the photo detector. 
         FIG. 10  is a simplified side cutaway view illustration of a non-intrusive monitor system wherein the optical element is a set of two discs and a cylinder with collimated faces and a photo detector, wherein the cylinder is fully transparent and has a notch on its side faces opposite the photo detector, thereby reflecting part of the collimated beam that may come from each direction onto the photo-detector;  FIG. 10  also shows the dispersed light reflected onto the photo detector. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Reference is now made to  FIG. 1 , which illustrates a non-intrusive monitoring system  1 , in accordance with an embodiment of the present invention, which includes a fiber optic connection with an optical element ferrule and photo detector, as is now described. 
     A first connector  3  is connected to an end of a first fiber optic line  2 . The first connector  3  includes a first ferrule  4 , which is inserted into one end of a centering tube  5 . Similarly, a second connector  7  is connected to an end of a second fiber optic line  8 . The second connector  7  includes a second ferrule  6 , which is inserted into an opposite end of centering tube  5 . Tube  5  centers the core  85  and the cladding  14  ( 85  and  14  are shown in  FIG. 3.2 ) of the fiber optic lines in the ferrules. 
     Reference is now made to  FIGS. 2.1, 2.2 and 3.1 . An inner optical element ferrule  13  (also referred to as an intermediate ferrule) with a side opening  16  (seen in  FIGS. 2.2 and 3.1 ) is centered in centering tube  5  between first ferrule  4  and second ferrule  6 . The inner optical element ferrule  13  firmly contacts the end of first ferrule  4  at first contact area  11  and firmly contacts the end of second ferrule  6  at second contact area  12 . Photo detector  15 , having lead wires  17 , is mounted on inner optical element ferrule  13 . The side opening  16  is cut in the inner optical element ferrule  13  and photo detector  15  may be mounted in this opening, as seen in  FIG. 3.1 . 
     Reference is now made to  FIG. 3.2 . It is seen that the side opening  16  of inner optical element ferrule  13  cuts into the cladding  14  to expose an exposed portion  18  of cladding  14  without penetrating the core  85  (also seen in  FIGS. 8.1 and 8.2 ). The photo detector  15  is mounted over the exposed portion  18  in cladding  14 . The invention exploits the normal loss of light transmission into the cladding of real-world, non-perfect optic fibers and harvests this small amount of light for detection by the photo detector. 
     Reference is now made to  FIGS. 4-7 , which illustrate a non-intrusive monitoring system  24 , in accordance with another embodiment of the present invention. Elements which are common to systems  1  and  24  are designated by the same reference numeral. System  24  differs from system  1  in that system  24  does not have an inner optical element ferrule that contacts the first and second ferrules and wherein the opening in the cladding for the photo detector is on the ferrule on the fiber optic line ending itself, as is now explained. 
     In system  24 , first connector  3  is connected to an end of first fiber optic line  2 . The first connector  3  includes first ferrule  4 , which is inserted into one end of a centering tube  5 . Similarly, a second connector  25  is connected to an end of a second fiber optic line  26 . The second connector  25  includes a second ferrule  27 , which is inserted into an opposite end of centering tube  5 . Tube  5  centers the core and the claddings in the ferrules. 
     The second ferrule  27  is formed with a side opening  30  (seen in  FIG. 6.2 ) cut into the ferrule  27  itself and into part of cladding  14  without penetrating the core  85  (seen in  FIGS. 8.1 and 8.2 ), thereby exposing an exposed portion  18  of the cladding of the fiber  27 . A photo detector  28 , having lead wires  17 , is mounted over the exposed portion  18 . As seen in  FIG. 7 , more than one photo detector may be mounted over the exposed portion  18  of the fiber, such as an additional photo detector  31 . 
     Reference is now made to  FIGS. 8.1 and 8.2 , which illustrate a non-intrusive monitoring system  81 , in accordance with another embodiment of the present invention. A first ferrule  83  and a second ferrule  86  are centered in a centering tube  82 , which may be C-shaped. An intermediate ferrule  84 , which is formed with a side opening  92 , is also centered in the C-shaped tube  82 . All the ferrules are firmly axially attached to each other. The claddings of the fiber optics in the ferrules are designated by the numeral  87  and the fiber optic cores are designated by the numeral  85 . The side opening  92  of intermediate ferrule  84  is formed in the fiber optic cladding  87  but does not penetrate the fiber optic core  85 . A light guide  89  is disposed in side opening  92 . As seen in  FIG. 8.2 , light guide  89  may be coated with light guide IR coating  97  that changes IR into visible light waves. 
     Reference is now made to  FIG. 9.1 , which illustrates a non-intrusive monitor system  98  in accordance with another embodiment of the present invention. 
     System  98  is a ferrule size lens set  98 , which may use the first ferrule  83  and second ferrule  86  of the previous embodiment. First ferrule  83  is firmly attached to a first disc  99  which is firmly attached to one end of a density filter cylinder  100 . Second ferrule  86  is firmly attached to a second disc  101  which is firmly attached to an opposite end of cylinder  100 . The two ends of cylinder  100  each have a collimating lens shape  106  and  109  (seen in  FIG. 9.2 ). Cylinder  100  may be coated with a reflecting coating on its reflecting side  107 . A light guide  113  is attached to a side of cylinder  100 . Light guide  113  is perpendicular to the cylinder axial axis and is opposite to the reflecting coating on the reflecting side  107 . 
     Reference is now made to  FIG. 9.2 . Light  104  exits second ferule  86  and enters second disc  101  at a numerical aperture angle of light  105 . The light is collimated into a collimated beam  103  in density filter cylinder  100  by first collimating face  106 . Most of the light in collimated beam  103  reaches second collimating face  109  and exits therefrom as light rays  110  which combine as light beam  111  in first ferrule  83 . Part of the light in collimated beam  103  is dispersed in density filter cylinder  100  as light rays  108 . Light  108 , together with light reflected from reflecting coating  107 , enters light guide  113  (which may or may not be coated with an IR coating, as described above). 
     Reference is now made to  FIG. 9.3 . The light  108  dispersed in density filter cylinder  100  and the light reflecting from reflecting coating  107  is directed towards light guide  113  as dispersed and reflected light  112 . The discs and the faces of the cylinder may be coated with anti-reflecting coating. 
     Reference is now made to  FIG. 10 . The system of  FIG. 10  is similar to the system of  FIGS. 9.1-9.3 , except that in the system of  FIG. 10  a clear cylinder  119  is employed which is formed with a coated notch  116  with notch reflecting coating faces  117 . In this embodiment, most of the light from collimated beam  103  reaches first collimating face  109  and is collimated into light in first ferrule  111 . Part of the light in collimated beam  103  is reflected by notch reflecting coating faces  117  as reflected beam  118  which is directed towards light guide  113 . Light guide  113  may be provided with a photo detector  128  and may or may not be coated with an IR coating, as described above.