Abstract:
An apparatus for illuminating optical fibers, said apparatus includes a housing having a face; fiber ports disposed on said face, each of said fiber ports being configured to engage a connector on an optical fiber; port lamps, each being disposed to provide light through a corresponding one of said fiber ports; and a control system configured to cause said port lamps to provide light according to corresponding port signatures, said port signatures being distinct from each other.

Description:
BACKGROUND 
     In many communication systems, bundles of optical fibers extend significant distances between two points. In many office buildings, these bundles of fibers terminate in a wiring closet. In a typical wiring closet, there may be hundreds of optical fibers. Upon leaving the wiring closet, these fibers diverge along different paths, extending through ceilings and walls to various other termination points in different parts of the building. In some cases, fibers that begin in a wiring closet extend to neighboring buildings. 
     In many cases, the fibers appear identical to each other. Accordingly, it is often difficult for maintenance personnel to determine which of the many wires in a closet is the one that extends to a particular location. To address this, difficulty, one typically shines a light through individual fibers and visually inspects the other ends of the fibers. 
     Occasionally, a few optical fibers will break, or otherwise lose continuity. Proper maintenance of such communication systems typically include identifying broken fibers. 
     One way to identify broken fibers is to shine a light at a first end and look at a second end to see if a light exits out the other end. However, this procedure is carried out one fiber at a time, and is therefore time consuming. 
     Another option is to shine a light through the first end of each of several fibers at the same time. However, even if one were to identify a fiber having a dark second end, it would not be possible to easily determine which fiber&#39;s first end the dark second end would correspond to. 
     SUMMARY 
     In one aspect, the invention features an apparatus for illuminating optical fibers. Such an apparatus includes a housing having a face; fiber ports disposed on the face, each of the fiber ports being configured to engage a connector on an optical fiber; port lamps, each being disposed to provide light through a corresponding one of the fiber ports; and a control system configured to cause the port lamps to provide light according to corresponding port signatures, the port signatures being distinct from each other. 
     Embodiments of the above apparatus include those in which port signatures comprise different colors, those in which port signatures comprise different rhythmic patterns, and those in which comprise different combinations of rhythmic patterns and colors. 
     Other embodiments of the above apparatus include those in which the plurality of port lamps comprises at least one LED port lamp, those in which the plurality of port lamps comprises at least one diode laser, and those in which the plurality of port lamps comprises at least one incandescent lamp. 
     Some embodiments also include a lens in optical communication with a port lamp from the plurality of port lamps, whereas others include a color filter in optical communication with a port lamp from the plurality of port lamps. 
     In some embodiments, the control system includes a first controller programmed to cause a first subset of the plurality of port lamps to blink according to a first rhythmic pattern, and a second controller programmed to cause a second subset of the plurality of port lamps to blink according to a second rhythmic pattern that differs from the first rhythmic pattern. 
     A variety of dispositions are also possible for the fiber ports. For example, in some embodiments, the fiber ports are disposed in an array that has two or more portions, each portion being associated with a different rhythmic pattern, so that each fiber port associated with a particular one of the plurality of portions has a port signature with the same rhythmic pattern. In other embodiments, the fiber ports are disposed in an array having two or more portions, each of which is associated with a different color, in which case each fiber port associated with a particular one of the plurality of portions has a port signature with the same color. In still other embodiments, the fiber ports are disposed in an array of rows and columns, with each fiber port in a particular column associated with a port signature having the same color, and in which each fiber port associated with a particular row has a port signature with the same rhythmic pattern. 
     In another aspect, the invention features an apparatus for passing light through each of a plurality of optical fibers. Such an apparatus includes a plurality of means for receiving an optical fiber; means for providing light to a first means for receiving an optical fiber; means for providing light to a second means for receiving an optical fiber; means for causing the means for providing light to a first means for receiving an optical fiber to cause the light to be provided according to a first port signature; and means for causing the means for providing light to a second means for receiving an optical fiber to cause the light to be provided according to a second port signature. 
     In some embodiments, the means for causing the means for providing light to a first means for receiving an optical fiber to cause the light to be provided according to a first port signature comprises means for providing light having a first color, and the means for causing the means for providing light to a second means for receiving an optical fiber to cause the light to be provided according to a second port signature comprises means for providing light having a second color that differs from the first color. 
     In other embodiments, the means for causing the means for providing light to a first means for receiving an optical fiber to cause the light to be provided according to a first port signature comprises means for providing light having a first rhythmic pattern, and the means for causing the means for providing light to a second means for receiving an optical fiber to cause the light to be provided according to a second port signature comprises means for providing light having a second rhythmic pattern that differs from the first rhythmic pattern. 
     In yet other embodiments, the means for causing the means for providing light to a first means for receiving an optical fiber to cause the light to be provided according to a first port signature comprises means for providing light having a first combination of a rhythmic pattern and a color, and the means for causing the means for providing light to a second means for receiving an optical fiber to cause the light to be provided according to a second port signature comprises means for providing light having a second combination of a rhythmic pattern and a color, the second combination being different from the first combination. 
     In yet another aspect, the invention features a method for testing a plurality of optical fibers. Such a method includes causing light having different port signatures to enter corresponding first ends of different optical fibers; and comparing port signatures of light received at the second ends of the different optical fibers. 
     Some practices of the method also include identifying a break in one of the first and second optical fibers at least in part on the basis of the comparison. 
     Other practices of the method also include, determining, based at least in part on the inspection, mapping each of the second ends to a corresponding first end. 
     These and other features of the invention will be apparent from the following detailed description and the accompanying figures in which: 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view of the apparatus described herein; 
         FIG. 2  shows a cross section of a fiber port from the apparatus of claim  1 ; 
         FIG. 3  shows the front face of the apparatus of  FIG. 1 ; 
         FIG. 4  shows a circuit for controlling the operation of the apparatus of  FIG. 1 ; and 
         FIG. 5  shows exemplary port signatures. 
     
    
    
     DETAILED DESCRIPTION 
     An apparatus  10  for testing continuity of optical fibers, as shown in  FIG. 1 , includes an array  12  of fiber ports  14  for receiving corresponding optical connectors or couplers at first ends of corresponding optical fibers. The fiber ports  14  are configured to accept one or more fiber-optic couplers, such as ST, SC, FC, FDDI (FDS) and ESCON (RSD). 
     As shown in  FIG. 2 , each fiber port  14  has an associated port lamp  18  for providing light that is ultimately placed on an optical fiber  19 . In some embodiments, the port lamps are LEDs. An LED port lamp is particularly useful because an LED can be pulsed with little loss of intensity, is available in a variety of colors, consumes little power, and provides an intense and relatively collimated beam. In addition, LEDs can turn on and off quickly. 
     For particularly long optical fibers, in which long range light transmission is advantageous, a semiconductor diode laser makes a useful port lamp  18 . In addition, a high intensity light bulb can be used as a port lamp  18 . 
     In some embodiments, the fiber port  14  can include a lens  16  for directing the light into a relatively narrow beam to be placed on the fiber. 
     To provide suitable colors, some embodiments use port lamps  18  having the desired colors. However, in other embodiments, a filter  20  is provided in series with the port lamp  18  to remove all but the desired wavelengths of light. 
     Referring back to  FIG. 1 , the apparatus  10  further includes a power input  22  for receiving AC power. Alternative embodiments rely on battery power, in which case a charger input  24  can be provided. In such embodiments, the battery is a long-lasting 9-volt NiCad battery. However, conventional household batteries, such as AAA, AA, C, and D batteries can be used. 
     A first switch  26  connects the light sources to a power supply. A suitable switch  26  is a slide switch such as the SS039-P023BA switch manufactured by T-MEC in Taiwan. 
     A second switch  28  causes the light source to operate in steady mode or in pulsed mode. In steady mode, the port lamps  18  burn steadily. In pulsed mode, the port lamps  18  flash according to a predetermined rhythm. 
     As shown in  FIG. 3 , each column  30  of the array  12  of fiber ports  14  is associated with a color and each row  32  is associated with a particular rhythmic pattern. In the illustrated embodiment, there are four colors: white, red, yellow, and green, and seven distinct rhythmic patterns, ranging from a constant light in the first row, a blinking light in the first row, a twice blinking light in the third row, and so on. The particular combination of a rhythmic pattern and a color defines a port signature associated with a fiber port  14 . As a result, when the apparatus  10  is powered on, it is a straightforward matter to identify each fiber port  14  by its port signature. 
     Referring now to  FIG. 4 , a control system  34  for controlling the port lamps  18  features plurality of programmable timers  36 , each of which has been preset to implement a particular rhythmic pattern. Each timer  36  controls all port lamps  18  that are in a particular timer  36  in  FIG. 2 . A suitable timer  36  is the 555 Timer, first introduced by Signetics Corporation in 1971, but now available from a variety of manufacturers as an integrated circuit. 
     In operation, one attaches, to each fiber port  14 , a first end of an optical fiber  19 . Then, one turns on the port lamps  18 . Because each port lamp  18  displays a unique combination of color and rhythmic pattern, one can inspect the second ends of each fiber and identify which second end corresponds to which first end. This greatly facilitates, for example, identifying a fiber with a discontinuity, or determining the second end of a fiber that corresponds to a particular first end. 
     A variety of rhythmic patterns can be used as a port signature or a part thereof. In one embodiment, the rhythmic pattern includes having a port lamp  18  turn on and off a pre-determined number of times with a 50% duty cycle at a flashing frequency of 3-5 Hz. This is followed by an intermission, during which the port lamp  18  does not flash, followed by a repeat of the same rhythmic pattern.  FIG. 5  shows exemplary port signatures distinguished from each other by different numbers of pulses. 
     The use of different rhythmic patterns significantly increases the number of possible port signatures, and hence the number of fibers that can be examined in parallel. In an embodiment that relies on different colors, one quickly exhausts the number of different colors that can reliably be distinguished by the human eye. In contrast, there is considerably more variety in rhythmic patterns. Although one embodiment features rhythmic patterns of equal length flashes, there is no reason the rhythmic pattern could not consist of long and short flashes, or combinations of shorter and longer gaps between flashes. 
     In another embodiment, the port lamp  18  may be configured to flash two or more colors in sequence. This embodiment creates additional combinations that allow more complex display characteristics for each fiber port  14 . 
     In general, the embodiments described herein have in common the ability to associate a particular port signature with each fiber port  14 . The port signature can be a color, a rhythmic pattern, of any combination thereof. Using the port signature, it is possible to identify, by inspecting the light at a second end of a fiber far away from the apparatus  10 , which second ends are associated with which first ends, thus greatly simplifying maintenance of fiber optic communication systems.