Multifiber connector, installation tool and associated methods of validating optical fiber continuity

FIELD OF THE INVENTION

0001The present invention relates generally to the connectorization of optical fibers and, more particularly, to multifiber connectors, installation tools and associated methods for validating optical fiber continuity during the connectorization process.

BACKGROUND OF THE INVENTION

0002Although fiber optic connectors can generally be most efficiently and reliably mounted upon the end portions of optical fibers in a factory setting during the production of fiber optic cable, many fiber optic connectors must be mounted upon the end portions of optical fibers in the field. As such, a number of fiber optic connectors have been specifically developed to facilitate field installation. One advantageous type of fiber optic connector that is specifically designed to facilitate field installation is the UNICAM® family of fiber optic connectors provided by Siecor Corporation of Hickory, North Carolina. While the UNICAM family of fiber optic connectors includes a number of common features including a common splicing technique, the UNICAM family of fiber optic connectors has several different styles of connectors including UNICAM connectors adapted to be mounted upon a single optic fiber and UNICAM connectors adapted to be mounted upon two or more optical fibers, such as the MT-RJ UNICAM connector. See, for example, U.S. Patent Application 09/108,451 filed July 1, 1998 and assigned to Siecor Corporation, which describes a multifiber connector, such as an MT-RJ UNICAM connector, adapted to be spliced onto the end portions of a plurality of optical fibers. The contents of this patent application are hereby incorporated by reference in their entirety.

0003By way of example of an advantageous fiber optic connector designed for field installation, Figure 1 depicts an MT-RJ UNICAM® connector <b>10.</b> The connector generally includes a ferrule <b>12</b> defining one or more bores for receiving respective optical fiber stubs. The optical fiber stubs are preferably sized such that one end of the optic fiber stubs extends rearwardly beyond the ferrule. The MT-RJ UNICAM® connector also includes splice components, at least one of which defines a groove for receiving an end portion of each optical field fiber upon which the fiber optic connector is to be mounted. In order to mount the fiber optic connector upon optical field fibers, the splice components are positioned proximate the rear end of the ferrule, such that the end portions of the optical fibers stubs that extend rearwardly beyond the ferrule are disposed within the respective grooves defined by the splice components. Thereafter, end portions of the optical field fibers can also be inserted into the respective grooves defined by the splice components. By inserting the optical field fibers into the grooves defined by the splice components until respective end portions of the optical fiber stubs and the optical field fibers make contact, optical connections can be established between respective pairs of the optical fiber stubs and the optical field fibers. In this regard, the contact between the end portions of the optical fiber stubs and the optical field fibers establishes optical continuity between respective pairs of the optical fiber stubs and the optical field fibers. The splice components can then be actuated, such as by means of a cam member <b>20</b>, in order to force the splice components together and to secure the end portions of the optical fiber stubs and the optical field fiber in position within the respective grooves defined by the splice components.

0004In order to facilitate the connectorization of optical fibers in the field, installation tools have also been developed. For example, U.S. Patent No. 5,040,867 to Michael de Jong et al. and U.S. Patent No. 5,261,020 to Michael de Jong et al. describe installation tools for facilitating the connectorization of optical fibers in the field. In addition, a UNICAM® installation tool kit is provided by Siecor Corporation of Hickory, North Carolina, to facilitate the mounting of the UNICAM® family of connectors upon the end portions of optical field fibers in the field. An installation tool holds a number of components of the fiber optic connector including the ferrule and the splice components while the optical field fibers are inserted into the fiber optic connector and aligned with the respective optical fiber stubs.

0005In this regard, one conventional installation tool includes a base and a tool housing mounted upon the base. The installation tool also includes an adapter disposed within the tool housing. The adapter has a first end for engaging the fiber optic connector that is to be mounted upon the optical field fibers and an opposed second end that is a dust cap. The installation tool also includes a bias member mounted within the tool housing that engages a shoulder defined between the first and second ends of the adapter in order to secure the adapter in position within the tool housing. Typically, the bias member includes a slide member slidably connected to the tool housing and a biasing element, such as a spring, for urging the slide member into engagement with the shoulder defined by the adapter. The slide member generally includes an engagement portion having a U-shape through which the second end of the adapter extends. In addition, a conventional slide member includes a base portion disposed between the tool housing and the base and connected to the engagement portion by means of a connecting element that extends through a lengthwise extending slot defined by the tool housing. Thus, the movement of the connecting element through the slot defined by the tool housing guides the corresponding movement of the slide member in a lengthwise direction relative to the tool housing in order to engage the shoulder defined by the adapter, thereby securing the adapter in position within the tool housing.

0006In order to mount the fiber optic connector upon the end portions of the optical field fibers, the fiber optic connector is mounted within the installation tool. In particular, the forward end of the fiber optic connector is engaged by the first end of the adapter which, in turn, is secured within the tool housing once the slide member is biased into engagement with the shoulder defined by the adapter. The end portions of the optical field fibers are then inserted into the rear end of the fiber optic connector and the splice components are subsequently actuated, such as by being cammed together, in order to secure the optical field fibers relative to respective optical fiber stubs. The crimp tube <b>24</b> of the fiber optic connector is then crimped about the optical field fibers and, in some applications, a crimp band <b>26</b> is crimped to the strength members surrounding the optical field fibers in order to provide strain relief and otherwise protect the splice connections of the optical field fibers and the optical fiber stubs.

0007Once fiber optic connectors have been mounted upon the opposed end portions of the optical field fibers, the resulting fiber optic cable assembly is preferably tested end-to-end. Among other things, this testing is designed to insure that optical continuity has been established between the optical fiber stubs and respective optical field fibers. While fiber optic cables can be tested in different manners, one test involves the introduction of light having a predetermined intensity into each optical fiber stub. By measuring the light following its propagation through the fiber optic cable assembly and, more particularly, by measuring the insertion loss and back reflectance onto each optical fiber stub with a power meter, the continuity of each optical field fiber and the respective optical fiber stub can be determined. If the testing indicates that the optical fibers are not sufficiently continuous, the technician must either scrap the entire fiber optic cable assembly or, more commonly, replace one or both fiber optic connectors in an attempt to establish the desired continuity. In order to replace the fiber optic connectors, a technician generally removes, i.e., cuts off, one of the fiber optic connectors and repeats the connectorization process described above by mounting a new fiber optic connector within the installation tool and inserting the optical field fibers into the new fiber optic connector. Once the new fiber optic connector has been mounted upon the end portions of the optical field fibers, the new fiber optic connector is removed from the installation tool and the fiber optic cable assembly is again tested. If the optical fibers are still not sufficiently continuous, the fiber optic connector mounted upon the other end of the fiber optic cable assembly is typically removed and replaced as described above, prior to further testing of the resulting fiber optic cable assembly.

0008While fiber optic connectors and associated installation tools have been developed to facilitate the mounting of the fiber optic connectors upon the end portions of optical field fibers in the field, conventional field connectorization techniques can be quite time consuming and expensive. In this regard, since the continuity testing is not performed until after the fiber optic connectors have been completely mounted to the optical field fibers, one or both of the fiber optic connectors must typically be replaced if the testing indicates a discontinuity between the optical field fibers and the respective optical fiber stubs. This process not only requires additional time to effect the reconnectorization, but also increases the cost of the resulting fiber optic cable assembly by causing a number of potentially functional fiber optic connectors to be disadvantageously scrapped since the testing generally does not indicate which of the fiber optic connectors should be replaced. In this regard, the technician generally randomly picks one of the fiber optic connectors to replace, thereby insuring that a fiber optic connector that has been appropriately mounted upon the optical field fibers is replaced almost half of the time.

0009The reconnectorization of one or both ends of a fiber optic cable assembly is particularly troublesome for fiber optic cable assemblies that include a plurality of optical field fibers. In this regard, if the testing indicates a discontinuity involving any one of the optical field fibers, the fiber optic connectors mounted upon one or both ends of the fiber optic cable assembly must generally be replaced, even if the other optical field fibers and the optical fiber stubs have the desired continuity.

0010In order to facilitate continuity testing while the fiber optic connector remains mounted within the installation tool, Siecor Corporation previously developed a modified installation tool for a single fiber CamLite™ ST connector that permitted continuity testing. The installation tool included an adapter having opposed first and second ends, the first end of which was adapted to engage a single fiber CamLite ST connector. In order to test the continuity of the optical fiber, a laser, such as an HeNe gas laser, was provided that delivered red light to the optical fiber stub of the single fiber CamLite ST another ST connector was mounted. This other ST connector was, in turn, inserted into the second end of the adapter such that the red light was delivered to the optical fiber stub of the single fiber CamLite ST connector. By monitoring the glow emanating from the end portion of the optical fiber stub within the fiber optic connector through a translucent connector body, the technician could determine when contact was established between the optical fiber stub and the optical field fiber based upon the dissipation of the glow, i.e., continuity is presumed to have been established once the glow dissipates. Thereafter, the cam member of the single fiber CamLite ST connector could be actuated to fix the relative positions of the optical field fiber and the optical fiber stub prior to making a final check of continuity.

0011While the installation tool developed by Siecor Corporation for the single fiber CamLite ST connector advantageously monitored the continuity of an optical field fiber and an optical fiber stub while the single fiber CamLite ST connector remained within the installation tool, this installation tool provided no mechanism for uncamming and repositioning the optical field fiber relative to the optical fiber stub if the continuity was inadequate after cam actuation. As such, the fiber optic connector would still have to be removed from the end portion of the optical fiber and replaced by a new single fiber CamLite ST connector if testing subsequently determined that the optical field fiber and the optical fiber stub were actually discontinuous. In addition, the modified installation tool developed by Siecor Corporation was only capable of mounting a fiber optic connector upon a single optical fiber and, more particularly, mounting a CamLite ST connector upon a single optical fiber and did not permit multifiber connectors to be mounted upon the end portions of a plurality of optical field fibers. As such, improved techniques for mounting multifiber connectors upon optical field fibers in the field and for testing the resulting fiber optic cable assembly are desired in order to reduce the overall time required for the mounting and testing procedures and to correspondingly reduce the cost of the resulting fiber optic cable assembly.

SUMMARY OF THE INVENTION

0012Methods are therefore provided according to the present invention for validating the continuity of one or more optical fibers upon which a fiber optic connector is mounted. According to one embodiment, the fiber optic connector can be mounted upon an optical field fiber by actuating a cam mechanism to secure the optical field fiber in position relative to an optical fiber stub. If subsequent evaluation indicates that the continuity of the optical field fiber and the optical fiber stub is unacceptable, the cam mechanism can be deactuated, the optical field fiber can be repositioned and the cam mechanism can be reactuated without having to remove and replace the fiber optic connector. In order to determine if continuity has been established between the optical field fibers and respective optical fiber stubs, a method is also provided that introduces light into at least one of each pair of optical field fibers and optical fiber stubs and that only secures the position of each optical field fiber relative to the respective optical fiber stub once the glow associated with each pair of optical field fibers and optical fiber stubs dissipates, which dissipation indicates the establishment of continuity. An improved multifiber connector and installation tool are also provided to facilitate the establishment and validation of the continuity of optical field fibers and optical fiber stubs in order to reduce the time and cost required to connectorize optical field fibers in the field.

0013According to one advantageous embodiment, a method is provided for validating the continuity of an optical fiber upon which a fiber optic connector is mounted. In this regard, the fiber optic connector includes a ferrule defining at least one bore extending between opposed front and rear faces, an optical fiber stub extending through the bore and beyond the rear face of the ferrule, and a cam mechanism. According to this embodiment, an optical field fiber is advanced into the fiber optic connector while light is introduced into at least one of the optical field fiber and the optical fiber stub. So long as the optical field fiber and the optical fiber stub are discontinuous, a glow will emanate from an end portion of the optical field fiber or the optical fiber stub into which light is introduced. The glow is monitored while the optical field fiber is advanced into the fiber optic connector and further advancement of the optical field fiber is halted once the glow dissipates. The cam mechanism is then actuated to secure the optical field fiber in position relative to the optional fiber stub. Once the cam mechanism has been actuated, the continuity of the optical field fiber and the optical fiber stub is evaluated, preferably while the fiber optic connector remains within the installation tool. If the continuity of the optical field fiber and the optical fiber stub is unacceptable, the cam mechanism is deactuated. The optical field fiber is then repositioned relative to the optical fiber stub. In this regard, the optical field fiber is typically cleaved and cleaned prior to the repositioning to improve the resulting connection. Once the optical field fiber has been repositioned, the cam mechanism is reactuated. The evaluation of the continuity of the optical field fiber and the optical fiber stub as well as any necessary deactuation of the cam mechanism, repositioning of the optical field fiber and reactuation of the cam mechanism can be repeated as necessary to achieve continuity. Once acceptable continuity is obtained, the fiber optic connector can be crimped onto the optical field fibers and, more typically, to the strength members surrounding the optical field fibers.

0014By permitting repeated repositioning of the optical field fiber prior to crimping the fiber optic connector onto the optical field fibers, the method of this embodiment prevents otherwise acceptable fiber optic connectors from being replaced in an attempt to establish continuity between optical field fibers and optical fiber stubs. Thus, the total time required to mount the fiber optic connectors upon the optical field fibers and to validate the resulting continuity of the optical fibers is decreased according to the method of this embodiment of the present invention. Correspondingly, the cost of the resulting fiber optic cable assembly, on average, is also decreased since fewer fiber optic connectors are removed and scrapped.

0015In order to permit the glow emanating from the end portion of at least one optical fiber stub or optical field fiber that is indicative of a discontinuity to be viewed, a multifiber connector is also provided according to another embodiment of the present invention. The multifiber connector of this embodiment includes a multifiber ferrule extending lengthwise between opposed front and rear faces for receiving a plurality of optical fiber stubs. The multifiber connector also includes splice components positioned proximate the rear face of the multifiber ferrule for aligning a plurality of optical field fibers with respective ones of the plurality of optical fibers stubs. The multifiber connector also includes a cam mechanism for urging the splice components together to operably interconnect respective pairs of the optical field fibers and the optical fibers stubs. According to this embodiment of the present invention, at least one of the cam mechanism and the splice components is translucent such that the glow emanating from therewithin that is indicative of a discontinuity between at least one pair of optical field fibers and optical fibers stubs is externally visible.

0016In one embodiment, the cam mechanism of the multifiber connector includes a sleeve in which the splice components are disposed. The sleeve of this embodiment also defines a window through which the splice components are exposed. In addition to the sleeve, the cam mechanism of this embodiment includes a cam member disposed upon the sleeve for engaging the splice components via the window defined by the sleeve. As such, movement of the cam member relative to the sleeve urges the splice components together. In this embodiment, the cam member is typically translucent. As such, the multifiber connector of this embodiment of the present invention permits the connectorization process to be monitored to ensure that continuity is established between each optical field fiber and the respective optical fiber stubs prior to actuating the cam mechanism to secure the optical field fibers in position relative to the respective optical fiber stubs.

0017An installation tool is also provided according to another embodiment of the present invention for mounting the fiber optic connector upon one or more optical field fibers. The installation tool of this embodiment is capable of being converted between a first configuration that facilitates validation of the continuity of the optical fibers and a second configuration in which the continuity of the optical fibers is untested.

0018According to this embodiment, the installation tool includes a tool housing extending lengthwise between first and second opposed ends. The installation tool also include first and second adapters capable of being alternately mounted within the tool housing to configure the installation tool in the first and second configurations, respectively. The first adapter has a first end adapted to engage the fiber optic connector that is being mounted upon the optical field fiber and an opposed second end adapted to engage a fiber optic connector that is mounted upon another optical fiber that delivers light for continuity testing. While the second adapter also has a first end adapted to engage the fiber optic connector that is mounted upon the optical field fiber, the second end of the second adapter serves as a dust cap. Each adapter further defines a shoulder between the opposed first and second ends. The installation tool of this embodiment of the present invention also includes first and second bias members capable of being alternately mounted within the tool housing to configure the installation tool in the first and second configurations, respectively. The bias members are adapted to be biased into engagement with the shoulder defined by the respective adapter to thereby secure the respective adapter in position within the tool housing.

0019According to this embodiment of the present invention, the first and second adapters and the first and second bias members can be interchanged to convert the installation tool between the first and second configurations without otherwise disassembling the installation tool. In this regard, the first adapter and the first bias member can be mounted within the tool housing such that the installation tool has the first configuration that permits testing of the continuity of the optical fibers upon which the fiber optic connector is mounted. Alternatively, the second adapter and the second bias member can be mounted within the tool housing such that the installation tool has the second configuration that does not support continuity testing, but appears and functions in the same manner as a conventional installation tool.

0020According to this embodiment of the present invention, each bias member preferably includes a slide member and a biasing element for urging the respective slide member into engagement with the shoulder defined by the respective adapter to thereby secure the respective adapter and connector in position within the tool housing. Moreover, each slide member can include an engagement portion capable of being disposed within the tool housing for engaging the shoulder defined by the respective adapter and a base portion disposed on the opposite side of the tool housing from the engagement portion. In addition, each slide member can include a removable connector interconnecting the engagement portion and the base portion. The removable connector extends through a slot defined by the tool housing such that the removable connector rides within the slot as the slide member moves relative to the tool housing. Each slide member preferably includes a common base portion. As such, by removing the removable connector, the engagement portions of the first and second adapters can be interchanged and mounted to the common base portion without otherwise disassembling the installation tool.

0021Accordingly, the installation tool can be configured to support continuity testing of a fiber optic connector that remains mounted within the installation tool. Alternatively, the installation tool can be configured as a conventional installation tool that does not support continuity testing. By permitting continuity testing without removing the fiber optic connector from the installation tool, however, the installation tool of this embodiment of the present invention further facilitates the rapid repositioning of the optical field fibers relative to the optical fiber stubs in order to achieve continuity without having to scrap the fiber optic connector as required by conventional techniques.

BRIEF DESCRIPTION OF THE DRAWINGS

0022<ul id="ul0001" list-style="none" compact="compact"><li>Figure 1 is an exploded perspective view of an MT-RJ UNICAM® fiber optic connector.</li><li>Figure 2 is an exploded perspective view of an installation tool according to one embodiment of the present invention.</li><li>Figure 3 is a perspective view of the installation tool of Figure 2 following assembly thereof.</li><li>Figure 4 is a fragmentary perspective view of the installation tool of Figures 2 and 3 having at least portions of the MT-RJ UNICAM fiber optic connector of Figure 1 mounted therein.</li><li>Figure 5a is an exploded perspective view of a portion of the installation tool of Figures 2-4 illustrating the adapter and slide member that define the first configuration of the installation tool.</li><li>Figure 5b is an exploded perspective view of a portion of the installation tool of Figures 2-4 illustrating the adapter and slide member that define the second configuration of the installation tool.</li><li>Figure 6 is a flow chart illustrating the operations performed in order to validate the continuity of one or more optical field fibers with respective optical fiber stubs according to one embodiment of the present invention.</li></ul>

DETAILED DESCRIPTION OF THE INVENTION

0023The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

0024A method is provided according to the present invention for validating the continuity of one or more optical field fibers with respective optical fiber stubs carried by a fiber optic connector mounted upon end portions of the optical field fibers. While the method of the present invention can be utilized to perform continuity testing following the mounting of a variety of different fiber optic connectors upon the end portions of the optical field fibers, the method will be hereinafter described by way of example, and not of limitation, in conjunction with continuity testing performed following the mounting of a MT-RJ UNICAM® connector upon the end portions of a pair of optical field fibers.

0025As depicted in Figure 1 and described in more detail in U.S. Patent Application Serial Number 09/108,451, an MT-RJ UNICAM connector <b>10</b> is a multifiber connector having a multifiber ferrule <b>12.</b> A number of optical fiber stubs extend through and are secured within the multifiber ferrule. Depending upon the eventual application of the multifiber connector and the type of optical fibers upon which the connector will be mounted, the optical fiber stubs can be either multi-mode or single mode optical fiber stubs. In any event, the ferrule defines a plurality of bores that open through a front face of the ferrule for receiving respective optical fiber stubs. While the multifiber ferrule of the illustrated embodiment includes two bores, the multifiber ferrule can include any number of bores depending upon the number of optical field fibers upon which the fiber optic connector is to be mounted. The optical fiber stubs are preferably secured within the multifiber ferrule and, more particularly, within respective bores defined by the ferrule by means of an epoxy or other adhesive.

0026Once the optical fiber stubs have been secured within the multifiber ferrule <b>12,</b> the front face of the multifiber ferrule, including the end portions of the optical fiber stubs that are exposed via the bores opening through the front face of the ferrule, is precision polished. Although the multifiber connector <b>10</b> is particularly well-suited for field installation, the optical fiber stubs are preferably secured within the multifiber ferrule and the front face of the multifiber ferrule are preferably polished in the factory. The optical fiber stubs also preferably extend rearwardly beyond the rear face of the multifiber ferrule. In this regard, the ends of the optical fiber stubs that extend rearwardly beyond the rear face of the multifiber ferrule have typically been precision cleaved in order to facilitate subsequent splicing to respective optical field fibers.

0027The multifiber connector <b>10</b> also generally includes a sleeve <b>22,</b> typically termed a ferrule holder, defining a lengthwise extending passageway for at least partially receiving the ferrule <b>12.</b> For example, the second end of the ferrule is typically secured within one end of the passageway defined by the ferrule holder by means of an epoxy or other adhesive or by means of ultrasonic welding or the like. The multifiber connector also includes splice components disposed within the ferrule holder. As described in copending U.S. Patent Application Serial No. 09/108,451, the splice components are commonly formed of first and second splice portions or splice halves which are urged together to securely engage end portions of the optical fiber stubs and the optical field fibers. In this regard, at least one of the splice components defines grooves for receiving the end portions of the optical fiber stubs and the optical field fibers.

0028Once assembled as shown in Figure 1, the ferrule holder <b>22</b> secures the splice components within the lengthwise extending passageway such that the insertion of the rear end of the multifiber ferrule <b>12</b> into the passageway correspondingly inserts the end portions of the optical fiber stubs that extend beyond the rear face of the multifiber ferrule into respective grooves defined by the splice components. The assembled components of the fiber optic connector <b>10</b> can then be inserted into a housing <b>30.</b> In addition, the fiber optic connector can include a spring <b>32</b> and an annular spring push member <b>34</b> that are mounted upon the ferrule holder and that engage the housing in order to resiliently bias the ferrule forwardly in a longitudinal direction relative to the housing. In order to fabricate a male connector, the fiber optic connector may also include a pin keeper <b>16</b> that retains a pair of guide pins <b>18.</b> During assembly, the forward end of the ferrule can be extended through an opening defined by the pin keeper prior to inserting the ferrule and the ferrule holder into the housing. As such, the guide pins are positioned in respective guide pin passageways <b>14</b> defined by the ferrule and extend beyond the front face of the housing.

0029Once in the field, the end portions of the optical field fibers can also be inserted into respective grooves from the opposite end of the splice components so as to be aligned with and optically connected with respective optical fibers stubs. In this regard, the multifiber connector <b>10</b> can also include a crimp tube <b>24</b> through which the end portions of the optical field fibers are extended prior to insertion into respective grooves defined by the splice components, thereby facilitating the insertion of the optical field fibers into the respective grooves defined by the splice components.

0030The ferrule holder <b>22</b> preferably defines a window (not shown) and the splice components preferably include a keel. As such, the splice components can be disposed within the passageway defined by the ferrule holder such that the keel is positioned within the window defined by the ferrule holder and is exposed through the window for facilitating actuation of the splice components. The multifiber connector also includes a cam member <b>20</b> that is mounted upon the ferrule holder. The cam member is designed to engage the keel of the splice components that is exposed through the window defined by the ferrule holder. In addition to engaging the exposed keel, the cam member is adapted to actuate the splice components, such as by urging the first and second portions of the splice components toward one another as the cam member is rotated relative to the ferrule holder from a first unactuated position to a second actuated position. Upon actuation of the splice components, the end portions of the optical fiber stubs and the optical field fibers are mechanically coupled or spliced. Further details regarding the manner in which the cam member actuates the splice components are provided by U.S. Patent Application Serial No. 09/108,451, the contents of which have been incorporated herein by reference.

0031Once the splice components have been actuated and the continuity of the optical fiber stubs and the optical field fibers has been validated as described below, the crimp tube <b>24</b> can be crimped about the optical field fibers and the remainder of the components of the fiber optic connector <b>10</b> can be assembled. For example, the fiber optic connector can include an annular crimp band <b>26</b> that is mounted over the crimp tube and upon the end portion of the ferrule holder <b>22</b> proximate the cam member <b>20.</b> The crimp band can also be crimped inwardly in order to engage strength members associated with the optical field fibers that are positioned between the crimp band and the ferrule holder. A boot <b>36</b> that has that been previously mounted upon the optical field fibers can also be inserted into the rear end of the housing <b>30</b> so as to provide strain relief for the optical field fibers.

0032The method for validating the continuity of the optical field fibers and the optical fiber stubs according to the present invention is particularly advantageous for applications in which the fiber optic connector <b>10</b> is mounted upon the optical field fibers in the field. As such, an installation tool <b>40</b> is provided according to one embodiment of the present invention to facilitate mounting of the fiber optic connector upon the end portions of the optical field fibers. In this regard, Figures 2 and 3 depict an exploded perspective view and an assembled perspective view, respectively, of an installation tool. The installation tool typically includes a base <b>42.</b> Mounted to the base, typically by means of set screws <b>44,</b> are a fiber holder <b>46</b> for holding the optical field fibers, an anvil <b>48</b> for facilitating the crimping of crimp tube <b>24</b> during assembly of the fiber optic connector, and a tool housing <b>50.</b> The installation tool also includes a wrench <b>52</b> mounted to the tool housing for engaging the cam member <b>20</b> of the fiber optic connector and permitting actuation thereof. The installation tool further includes an adapter <b>54</b> that is mounted within the tool housing and a bias member <b>57</b> that is also mounted within the tool housing for securing the adapter in position therewithin.

0033As shown in Figures 5a and 5b, the adapter <b>54</b> has opposed first and second ends <b>56, 58</b> and defines a shoulder <b>60</b> therebetween. The first end of the adapter is designed to engage the fiber optic connector <b>10</b> that is being mounted upon the end portions of the optical field fibers. In embodiments in which an MT-RJ UNICAM connector is to be mounted upon the end portions of the optical field fibers, the first end of the adapter is designed to engage the housing <b>30</b> of the MT-RJ UNICAM connector, such as by being sized and shaped to receive the housing of the MT-RJ UNICAM connector and defining windows for receiving and engaging corresponding tabs that extend outwardly from the housing.

0034According to the present invention, the installation tool <b>40</b> includes first and second adapters <b>54</b> that can be alternately mounted within the tool housing <b>50</b> to configure the installation tool to have first and second configurations, respectively. As shown in Figure 5a, the second end <b>58</b> of the first adapter is also sized and shaped to engage another fiber optic connector, typically of the same type engaged by the first end <b>56</b> of the adapter. As will be described below, the fiber optic connector engaged by the second end of the first adapter is mounted upon the end portion of an optical fiber that serves to deliver light for testing the continuity of the optical fiber stubs and the optical field fibers. Even though the first and second ends of the first adapter are both typically designed to engage the same type of fiber optic connectors, the first and second ends of the first adapter are preferably sized differently so as to thereby define a shoulder <b>60</b> that can be engaged by the bias member <b>57.</b> In contrast to the first adapter, the second adapter is of a more conventional design and has a closed second end that functions as a dust cap. Since the second end of the second adapter is not designed to engage another fiber optic connector, the second adapter is generally smaller than the first adapter.

0035By providing two different adapters <b>54</b>, the installation tool <b>40</b> of the present invention can be differently configured depending upon its application. For example, the first adapter can be mounted within the tool housing <b>50</b> in order to facilitate continuity testing of the optical fiber stubs and the optical field fibers while the fiber optic connector <b>10</b> is mounted within the installation tool as will be described in more detail hereinafter. By mounting the second adapter within the tool housing, however, the installation tool of the present invention can operate in a more conventional manner by facilitating the mounting of the fiber optic connector upon the end portions of the optical field fibers without permitting continuity testing of the optical fiber stubs and the optical field fibers. Also, as described below, the second adapter could be used if the light source is attached to the optical field fibers rather than the optical fiber stubs.

0036Since the first and second adapters <b>54</b> are generally of different sizes, the installation tool <b>40</b> of the present invention also generally provides first and second bias members <b>57</b> adapted to engage the first and second adapters, respectively. In this regard, each bias member generally has a U-shape and defines a channel <b>67</b> through which the respective adapter extends. In this regard, the channel defined by the first bias member is preferably larger than the channel defined by the second bias member since the first adapter is also generally larger than the second adapter.

0037Each bias member <b>57</b> includes a slide member <b>62</b> capable of being mounted within the tool housing <b>50</b> and a biasing element <b>64</b> for urging the respective slide member into engagement with the shoulder 60 defined by the respective adapter <b>54.</b> As shown in Figures 2, 5a and 5b, each slide member typically includes an engagement portion 66 disposed within the tool housing for engaging the shoulder of the respective adapter. In this regard, the engagement portion is generally U-shaped and defines the channel through which the second end <b>58</b> of the respective adapter extends. Each slide member also includes a base portion <b>68</b> disposed on the opposite side of the tool housing from the engagement portion. In this regard, the base portion is typically disposed between the tool housing and the base <b>42.</b> In addition, each slide member includes a removable connector <b>70</b> interconnecting the engagement portion and the base portion. As depicted in Figure <b>2</b>, the tool housing preferably defines a lengthwise extending slot <b>72.</b> As such, the removable connector can extend through the slot defined by the tool housing in order to connect the engagement portion and the base portion and can ride within the slot as the slide member moves lengthwise relative to the tool housing.

0038The biasing element <b>64,</b> such as a spring, typically engages the base portion <b>68</b> of each slide member <b>62</b> so as to bias or urge the slide member in a predetermined direction, such as to the right in Figure 4. Thus, the adapter <b>54</b> can be secured in position between an upstanding portion of the tool housing and the slide member. For example, the slide member depicted in Figure 4 can be moved to the left by a technician and an adapter inserted between the slide member and an upstanding portion of the tool housing. Once the slide member is released by the technician, the biasing element urges the slide member to the right and into contact with the shoulder <b>60</b> of the adapter, thereby securing the adapter and connector housing <b>30</b> against the upstanding portion of the tool housing.

0039By utilizing a common base portion <b>68</b> and a common biasing element <b>64</b>, the installation tool <b>40</b> can be readily converted between the first and second configurations without substantially disassembling the installation tool. In order to change from the first configuration of the installation tool to the second configuration, the first adapter <b>54</b> is removed from the installation tool and the removable connector <b>70</b> is removed in order to disconnect the engagement portion <b>66</b> and the base portion <b>68.</b> The engagement portion of the first bias member <b>57</b> is then replaced with the engagement portion of the second bias member and the removable connector is reinserted. Thereafter, the second adapter is inserted into the tool housing <b>50</b> to complete the reconfiguration process. By reversing these steps, the installation tool can also be easily converted from the second . configuration to the first configuration, if so desired. Accordingly, the installation tool need not be disassembled, such as by removing the tool housing, or any other component from the base <b>42</b>, in order to be reconfigured. Thus, the same installation tool can function as a conventional installation tool in the second configuration in which a dust cover is mounted to the fiber optic connector <b>10</b> that is being mounted upon the end portions of the optical field fibers and which does not support continuity testing while the fiber optic connector is mounted within the installation tool, as well as a modified installation tool in the first configuration which permits continuity testing to be performed while the fiber optic connector is mounted within the installation tool, as described in more detail below.

0040In order to test the continuity of the optical field fibers and the optical fiber stubs during the process of mounting a fiber optic connector <b>10</b>, such as a MT-RJ UNICAM® connector, upon the end portions of the optical field fibers, at least portions of the fiber optic connector are initially mounted within the installation tool <b>40</b> that is assembled to have the first configuration. See block <b>80</b> of Figure 6. In this regard, the fiber optic connector with the exception of the crimp band <b>26</b> and the boot <b>36</b> are assembled and the forward end of the housing <b>30</b> is inserted into the first end <b>56</b> of the adapter <b>54</b> for engagement therewith. While the crimp band and the boot are not assembled to the remainder of the fiber optic connector, the crimp band and the boot are mounted upon the optical field fibers prior to inserting the optical field fibers into the fiber optic connector. In addition to the engagement of the housing within the first end of the first adapter, the wrench <b>52</b> of the installation tool engages the cam member <b>20</b> of the fiber optic connector that has previously been mounted upon the ferrule holder <b>22.</b>

0041In order to test the continuity of the optical fiber stubs and the optical field fibers, a light source is provided, such as a diode laser, for producing light signals having predetermined characteristics, such as a predetermined intensity and/or wavelength. The light produced by the light source is introduced into at least one of each pair of the optical fiber stubs and the optical field fibers. See block <b>82.</b> As described hereinafter, the light is typically introduced into the optical fiber stubs. For example, in the illustrated embodiment in which a multifiber connector <b>10</b> is to be mounted upon a pair of optical field fibers, light is introduced into each of the two optical fiber stubs. While the light source can include a separate source for providing the light that is introduced into each optical fiber stub, a single light source is typically utilized with the light generated thereby being split prior to its introduction into the respective optical fiber stubs.

0042The light produced by the light source is typically delivered to the optical fiber stubs by means of one or more optical fiber jumpers upon which a fiber optic connector is mounted. Although not necessary, the fiber optic connector that is mounted upon the optical fiber jumpers from the light source is typically of the same type as the fiber optic connector <b>10</b> to be mounted upon the optical field fibers, such as an MT-RJ UNICAM® connector. The fiber optic connector associated with the optical fiber jumpers can therefore be inserted into the second end <b>58</b> of the adapter <b>54,</b> i.e., the first adapter, such that light generated by the light source is introduced into each optical fiber stub of the fiber optic connector to be mounted to the optical field fibers. Alternatively, the light source could be introduced from the opposite end of the optical field fibers, rather than from the connector end. In this manner, the light would emanate from the ends of the optical field fibers rather than the optical fiber stubs. With the light emanating from the optical field fibers, either of the adapters <b>54</b> could be used.

0043While the light source is introducing light into the optical fiber stubs, the optical field fibers are inserted into the rear end of the fiber optic connector <b>10</b> and advanced therethrough until contact is established with the respective optical fiber stubs. See block <b>84.</b> In the embodiment in which an MT-RJ UNICAM® connector is to be mounted upon a plurality of optical field fibers, the end portions of the optical field fibers are inserted through the crimp tube <b>24</b> and into respective grooves defined by the splice components. While the end portions of the optical field fibers are spaced apart from the optical fiber stubs, the light introduced into the optical fiber stubs generates a glow that emanates from the end portions of the optical fiber stubs within the splice components. Once the optical field fibers have made optical contact with the respective optical fiber stubs, either through direct physical contact or via index matching gel that is also disposed within the grooves defined by the splice components, the glow will dissipate since the light will be transmitted from the optical fiber stubs to respective optical field fibers. As such, the glow emanating from the end portions of the optical fiber stubs is preferably monitored as the optical field fibers are advanced into the fiber optic connector since the glow provides an indication of optical continuity. In order to permit the glow to be monitored, at least one of the cam mechanism and the splice components of the multifiber connector is translucent. Although one or all components could be translucent, the multifiber connector of one advantageous embodiment includes a cam member <b>20</b>, a ferrule holder <b>22</b> and splice components that are each translucent to permit the technician to monitor the glow emanating from the end portions of each optical fiber stub.

0044Once the optical field fibers appear to have made optical contact with the respective optical fiber stubs as indicated by the dissipation of the glow associated with each optical fiber stub, the optical field fibers are no longer advanced and the cam mechanism is actuated to secure the optical field fibers in position relative to the optical fiber stubs. See blocks <b>86</b> and <b>88.</b> In the embodiment in which an MT-RJ UNICAM connector <b>10</b> is mounted upon the end portions of a plurality of optical field fibers, the cam mechanism is actuated by rotating the cam member <b>20</b> relative to the ferrule holder <b>22</b> which, in turn, actuates the splice components and forces the splice components together, In order to facilitate the rotation of the cam member relative to the ferrule holder, the outwardly extending handle of the wrench <b>52</b> can be grasped by the technician and moved so as to rotate the cam member relative to the ferrule holder.

0045Once the cam mechanism has been actuated to secure the optical field fibers in position relative to the optical fiber stubs, the fiber optic connector <b>10</b> is evaluated to determine if the glow that previously emanated from the optical fiber stubs completely disappears, thereby indicating that the optical field fibers and the optical fiber stubs are continuous. See block <b>90.</b> If the glow has not been extinguished and the continuity is therefore unacceptable, the cam mechanism is deactuated. See block <b>92.</b> For example, the cam member <b>20</b> of an MT-RJ UNICAM® connector can be rotated relative to the ferrule holder <b>22</b> in order to deactuate the splice components by returning the wrench <b>52</b> to its original position. Thereafter, the optical field fibers can be repositioned relative to the optical fiber stubs. In addition to repositioning the optical field fibers, the optical field fibers can be withdrawn from the fiber optic connector, recleaved and cleaned prior to being reinserted into the fiber optic connector and repositioned. See block <b>94</b>. In this regard, the optical field fibers are generally cleaned of any index matching gel prior to being recleaved and thereafter recleaned with alcohol or the like.

0046During the repositioning of the optical field fibers, light continues to be introduced, typically into the optical fiber stubs, and the glow emanating from the end portions of the optical fiber stubs is again monitored to determine when continuity appears to have been established between each of the optical field fibers and the optical fiber stubs. Once the glow emanating from the end portion of each optical fiber stub dissipates, the cam mechanism can be reactuated to secure the optical field fibers in position relative to the optical fiber stubs. The fiber optic connector <b>10</b> can then again be inspected to determine if the glow has been completely extinguished. The repositioning and retesting of the continuity of the optical field fibers and the optical fiber stubs can be repeated as many times as necessary in order to obtain acceptable continuity between each pair of optical field fibers and optical fiber stubs.

0047Once the continuity of each pair of optical field fibers and optical fiber stubs has been verified by the extinguishment of the glow, the fiber optic connector <b>10</b> can be physically secured to the optical field fibers. In this regard, the crimp tube <b>24</b> is generally crimped about the optical fibers and, more commonly, about the buffer tubes. In order to crimp the crimp tube, the installation tool can include an arm <b>78</b> pivotally connected to the tool housing. By rotating the arm downwardly, the crimp tube can be compressed between the underside of the arm and the anvil <b>48,</b> thereby crimping the crimp tube radially inward about the ferrule holder and securing the strength members therebetween. See block <b>96.</b> Following crimping of the crimp tube, the arm is lifted and the fiber optic connector <b>10</b> is removed from the installation tool. See block <b>98.</b> A crimp band <b>26</b> is then typically slid over the optical field fibers and the crimp tube and about the rear end of the ferrule holder <b>22</b> such that the strength members that extend lengthwise along with the optical field fibers are positioned between the crimp band and the ferrule holder. Once properly positioned, the crimp band is crimped radially inward so as to securely couple the strength members of the fiber optic cable and the fiber optic connector. See block <b>100.</b> The boot <b>36</b> is then slid along the optical field fibers and inserted into the rear end of the housing so as to provide strain relief for the optical field fibers. See block <b>102.</b>

0048Although the continuity of the optical field fibers and the optical fiber stubs is confirmed by the extinguishment of the glow emanating from the optical fiber stubs, the continuity of the optical field fibers and the optical fiber stubs can be further and/or alternatively evaluated by an additional test. In this regard, the fiber optic connector <b>10</b> is removed from the installation tool <b>40</b> after the cam mechanism has been actuated to secure the optical field fibers and the optical fiber stubs, but prior to crimping the crimp tube <b>24</b> about the optical fibers. The fiber optic connector is removed from the installation tool by disengaging the housing <b>30</b> and the adapter <b>54</b> from the slide member <b>62.</b> The continuity of the optical field fibers and the optical fiber stubs can then be evaluated in a conventional manner. For example, a power meter, such as a JDS power meter, can be connected to the fiber optic connector through adapter 54 (functioning as a regular connector adapter) in order to introduce light into each pair of optical fiber stubs and optical field fibers and to measure attenuation of the light, typically by measuring the insertion loss and the back reflectance. If the insertion loss is unacceptably high or if the back reflectance is unacceptably low, it will generally be determined that the optical fiber stubs and the optical field fibers are not sufficiently continuous. Alternatively, if the insertion loss is relatively low and the back reflectance is relatively high, the testing will confirm that optical field fibers and the optical fiber stubs are continuous.

0049In either instance, the fiber optic connector <b>10</b> is then remounted within the installation tool <b>40</b> such as by inserting the housing <b>30</b> at least partially within the first end <b>56</b> of the first adapter <b>54.</b> If the continuity of the optical field fibers and the optical fiber stubs is unacceptable, the cam mechanism can be deactuated and the optical field fibers can be repositioned as described above and as shown in blocks <b>92</b> and <b>94.</b> If the continuity of the optical field fibers and the optical fiber stubs is acceptable, however, the crimp tube <b>24</b> is crimped about the optical fibers prior to removing the fiber optic connector from the installation tool and completing the assembly process as also described above and depicted in blocks <b>96-102.</b>

0050By monitoring the continuity of the optical field fibers and the optical fiber stubs while the optical field fibers are inserted into the fiber optic connector <b>10,</b> a technician can visually determine when continuity appears to have been established between each of the optical field fibers and the respective optical fiber stubs. In addition, by permitting the continuity to be further evaluated in the manner described above after actuating the cam mechanism and securing the optical field fibers in position relative to the optical fiber stubs, the continuity can be validated and, if it is determined that continuity has not actually been established between one or more of the optical field fibers and their respective optical fiber stubs, the cam mechanism can be deactuated, the optical field fibers can be repositioned, the cam mechanism reactuated and the process repeated until continuity is confirmed between each optical field fiber and the respective optical fiber stub.

0051Only once continuity is established between each optical field fiber and the respective optical fiber stub, as indicated by the extinguishment of the glow emanating from the optical fiber stubs, is the fiber optic connector <b>10</b> crimped onto the optical field fibers as described above. As such, the method and associated multifiber connector and installation tool <b>40</b> of the present invention reduce the time required to mount fiber optic connectors upon optical field fibers in the field and to test the continuity of the resulting optical connection. In addition, the method and the associated multifiber connector and installation tool of the present invention reduce the number of fiber optic connectors that must be scrapped, thereby reducing the overall costs associated with the connectorization of optical field fibers in the field.

0052Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.