Abstract:
A field installable fiber optic connector includes a housing, a spring element seat and a ferrule holder that is inserted from the rearward end of the housing. A spring element inserted into the front of the housing abuts the spring element seat. A spring element retainer attached to the ferrule holder abuts the forward portion of the spring element to compress the spring element and bias the ferrule holder forward. An optical fiber stub disposed between opposed splice members in an aligning groove terminates intermediate the ends of the splice members. An optical fiber is inserted between the splice members and guided by the groove into abutment with the end of the optical fiber stub. A cam disposed about the ferrule holder is movable to facilitate insertion of the optical fiber and to clamp the optical fiber and the optical fiber stub between the splice members.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to optical fiber connectors and more particularly to optical fiber connectors adapted for field installation. 
   2. Technical Background 
   Optical fibers are widely used in a variety of applications, including the telecommunications industry in which optical fibers are employed in a number of telephony and data transmission applications. Due, at least in part, to the extremely wide bandwidth and the low noise operation provided by optical fibers, the use of optical fibers and the variety of applications in which optical fibers are used are continuing to increase. For example, optical fibers no longer serve as merely a medium for long distance signal transmission, but are being increasingly routed directly to the home or, in some instances, directly to a desk or other work location. 
   With the ever increasing and varied use of optical fibers, it is apparent that efficient methods of coupling optical fibers, such as to other optical fibers, to a patch panel in a telephone central office or in an office building or to various remote terminals or pedestals, is required. However, in order to efficiently couple the signals transmitted by the respective optical fibers, an optical fiber connector must not significantly attenuate or alter the transmitted signals. In addition, the optical fiber connector must be relatively rugged and adapted to be connected and disconnected a number of times in order to accommodate changes in the optical fiber transmission path. 
   In order to provide the desired signal transmission characteristics, a number of optical fiber connectors have been developed which are mounted to the end portion of an optical fiber during a factory assembly process. By mounting the optical fiber connector to the optical fiber and/or optical fiber cable (hereinafter optical fiber) during an assembly process at the factory, the assembly of the optical fiber connector can be standardized such that inconsistent assembly and other problems associated with the field installation of the connector are avoided. 
   However, the factory installation of fiber optic connectors is not altogether satisfactory for every application. In particular, the factory installation of fiber optic connectors does not customize the installation process to account for the myriad of design variations experienced in the field. For example, by installing fiber optic connectors to the end portion of an optical fiber at the factory, the length of the connectorized optical fiber is fixed, thus requiring excess length and coiling to insure sufficient length for all applications. In addition, in many instances it is desirable to cut a length of optical fiber into a plurality of shorter lengths of optical fiber, each of which must be individually connected, such as by an optical fiber connector, to another optical fiber or to a patch panel or other type of terminal. However, the respective lengths of the shorter optical fibers cannot generally be determined until the optical fibers are installed in the field. Thus, in this instance, the requisite optical fiber connectors cannot be mounted to the fibers at the factory prior to installation of the optical fiber. Still further, it is desirable in many instances to package and ship optical fiber prior to the installation of the fiber optic connectors since the fiber optic connectors generally have a greater diameter than the respective optical fiber, and may unnecessarily complicate the packaging and shipping of the optical fiber. 
   Consequently, several optical fiber connectors have been developed which can be mounted to the end portion of an optical fiber in the field once the particular application of the optical fiber has been determined. For example, U.S. Pat. No. 5,040,867 which issued Aug. 20, 1991 to Michael de Jong et al. and which is assigned to the assignee of the present invention, discloses an optical fiber connector which is adapted for installation in the field. One commercial embodiment of the optical fiber connector of U.S. Pat. No. 5,040,867 is the Camlite® connector which is manufactured and distributed by Corning Cable Systems LLC of Hickory, N.C. 
   The Camlite® connector includes a lengthwise extending ferrule defining a longitudinal bore therethrough attached to a V-groove splice with a cam member for securing a fiber in the splice. A short length of optical fiber, typically termed an optical fiber stub, is disposed in the bore of the ferrule and extends into the V-groove splice. In the field, the end portion of an optical fiber, typically termed the field fiber, to which the optical fiber connector is to be connected, can be inserted in the V-groove splice from the end opposite the ferrule. Due to the precise alignment of the longitudinally extending V-groove within the Camlite® connector, the end portion of the field fiber is aligned with the optical fiber stub and thereafter held in place by activating the cam member. 
   The Camlite® connector can also include a crimp tube mounted to the end of the V-groove opposite the ferrule such that the field fiber extends therethrough. By compressing the crimp tube radially inward so as to contact the field fiber cable, the field fiber is fixed in position relative to the ferrule and the aligned optical fiber stub. The ferrule of the Camlite® connector can, in turn, be disposed within any of the standard connector housings. For example, the ferrule of the Camlite® connector is compatible with and can be mounted within an FC, ST or SC connector housing. The resulting Camlite® connector can then be connected, such as with an adapter or coupling sleeve, to the end portion of another optical fiber which also has an appropriate connector mounted to an end portion thereof. Alternatively, the resulting Camlite® connector can be connected to a patch panel, remote terminal or pedestal. 
   While the Camlite® connector is a great advance in the art, the Camlite® connector employs a cam member utilizing axial movement to establish a splice between the field fiber and the stub fiber. This may result in compressing together the abutting end faces of the optical fibers and potentially damaging the end faces. Moreover, The Camlite® connector, as with other field installable connectors, does not include a feature for readily and visually determining that an acceptable splice has been made. 
   SUMMARY OF THE INVENTION 
   A broad aspect of the invention includes a housing having an inner surface defining a cavity extending longitudinally therethrough and a spring element seat disposed therein, the housing also defining a forward opening in communication with the cavity and a rearward opening in communication with the cavity. The connector also comprises a spring element inserted into the cavity through the forward opening of the housing and a ferrule holder inserted into the cavity through the rearward opening of the housing. A spring element retainer is disposed about a forward end of the ferrule holder, and the spring element is disposed between the spring element seat and the spring element retainer thereby urging the ferrule holder forward with a predetermined spring force. Preferably, the predetermined spring force is greater than about 1 lb; more preferably between about 1 and 1.5 lbs; and most preferably between about 1.1 and 1.4 lbs. The optical fiber connector comprises a ferrule disposed within the ferrule holder, and an optical fiber stub disposed within the ferrule. The optical fiber connector according to an embodiment of the invention also comprises a view port for providing a visual indication of the quality of a splice between the optical fiber stub and a second optical fiber within the connector. 
   In another broad aspect of the invention an optical fiber connector is provided which includes a housing having an inner surface defining a cavity extending longitudinally and a spring element seat therein, the housing also defining a rearward opening in communication with the cavity and a forward opening in communication with the cavity. The optical fiber connector according to an embodiment of the invention further comprises a ferrule having first and second ends with a passageway disposed axially therebetween, and an optical fiber stub disposed within the ferrule passageway. A ferrule holder extends longitudinally between opposing first and second ends and defines a passageway extending longitudinally therebetween. The ferrule holder first end is inserted through the housing rearward opening and extends beyond the spring element seat. The ferrule holder is configured to hold the ferrule and is slidable longitudinally within the housing. A spring element retainer is disposed at the first end of the ferrule holder. A first and second opposed splice member are disposed within the ferrule holder, each splice member extending longitudinally from a first end proximate the second end of the ferrule to an opposite second end. One of the splice members includes a longitudinal fiber aligning groove wherein the optical fiber stub extends between the opposed splice members in the groove and terminates at a position intermediate the first and second ends of the splice members. A cam member having a first end, a second end and a passageway extending longitudinally therebetween is disposed about the ferrule holder. A spring element is disposed between the spring element seat and the spring element retainer, the spring element urging the ferrule holder forward with a predetermined spring force. The ferrule holder preferably comprises a stop disposed at an intermediate position between the ferrule holder first and second ends and configured to cooperate with the housing rearward opening. Preferably, the predetermined spring force is greater than about 1 lb; more preferably between about 1 lb. and 1.5 lbs; and most preferably between about 1.1 and 1.4 lbs. The optical fiber connector preferably comprises a port for providing a visual indication of the quality of a splice between the optical fiber stub and a field fiber. 
   In still another aspect of the invention, an optical fiber connector having a view port for providing a visual indication of the quality of a splice between a first and second optical fiber within the connector is disclosed. 
   In yet another broad aspect of the invention, a method of determining the quality of a splice between first and second optical fibers within an optical fiber connector is proposed, the method comprising passing a visible light through at least one of the optical fibers and viewing a view port on the connector for visual indication of the quality of a splice between the first and second optical fibers. Preferably, the visible light is a laser light or light from a light emitting diode (LED). The visual indication preferably comprises either the absence of visible light or the presence of light within the view port. 
   Although the optical fiber connector disclosed herein is generally described as an LC connector, it should be understood that the choice of an LC connector is for illustrative purposes only, and that the principals as described herein may be applied to other optical fiber connectors as well, such as SC, ST and FC connectors. 
   Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings. 
   It is to be understood that both the foregoing general description and the following detailed description present embodiments of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principles and operations of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of a fiber optic connector according to an embodiment of the present invention. 
       FIG. 2  is an end view of the rearward end of the connector housing of  FIG. 1  showing the alignment key. 
       FIG. 3  is a longitudinal cross section of the connector housing of  FIG. 1  taken along the line  3 — 3  in  FIG. 2 . 
       FIG. 4  is a perspective view of the connector housing of  FIG. 1  showing the latching arm and latching lugs. 
       FIG. 5  is an end view of the rearward end of the ferrule holder of  FIG. 1 . 
       FIG. 6  is a longitudinal cross section of the ferrule holder of  FIG. 1  taken along the line  6 — 6  in  FIG. 5 . 
       FIG. 7  is a longitudinal cross section of the ferrule and the optical fiber stub of  FIG. 1 . 
       FIG. 8  is a perspective view of the ferrule holder of  FIG. 1  showing the view port for providing a visual indication of the quality of a splice between the optical fiber stub and the field fiber, and showing the L-shaped groove for guiding the cam member. 
       FIG. 9  is an end view of the lead in tube of  FIG. 1 . 
       FIG. 10  is a perspective view of the lead in tube of  FIG. 1 . 
       FIG. 11  is a longitudinal cross section of the lead in tube of  FIG. 1  taken along the line  11 — 11  in  FIG. 9 . 
       FIG. 12  is a longitudinal cross section of the lead in tube of  FIG. 1  taken along the line  12 — 12  in  FIG. 9 . 
       FIG. 13  is a perspective view of the first and second splice members of  FIG. 1  showing the groove for aligning the optical fiber stub and the field fiber. 
       FIG. 14  is a longitudinal cross section of the fiber optic connector of  FIG. 1  shown in the fully assembled configuration. 
       FIG. 15  is an end view of the cam member of  FIG. 1  showing the major axis and the minor axis. 
       FIG. 16  is a longitudinal cross section of the cam member of  FIG. 1  taken along the line  16 — 16  in  FIG. 15 . 
       FIG. 17  is a perspective view of the cam member of  FIG. 1 . 
       FIG. 18  is a detailed view of the L-shaped groove of the ferrule holder shown in  FIG. 8  illustrating the ridges for retaining the inwardly extending projection of the cam member. 
       FIG. 19  is an end view of the splice members positioned within the ferrule holder with the cam member positioned on the ferrule holder and the keel portion of the second splice member aligned along the major axis of the cam member. 
       FIG. 20  is an end view of the splice members positioned within the ferrule holder with the cam member positioned on the ferrule holder and the keel portion of the second splice member aligned along the minor axis of the cam member. 
       FIG. 21  is a partial longitudinal cross section of the first end of the ferrule holder showing an exemplary attachment of the spring element retainer with a screw thread. 
       FIG. 22  is a partial longitudinal cross section of the first end of the ferrule holder showing an exemplary attachment of the spring element retainer with a ridge and groove. 
       FIG. 23  is a partial longitudinal cross section of the first end of the ferrule holder showing an exemplary attachment of the spring element retainer with a ridge and groove in an alternative configuration. 
       FIG. 24  is a perspective view of the trigger member of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   Detailed references will now be made to the drawings in which examples embodying this invention are shown. The drawings and detailed description provide a full and detailed written description of the invention, and of the manner and process of making and using it, so as to enable one skilled in the pertinent art to make and use it, as well as the best mode of carrying out the invention. However, the examples set forth in the drawings and detailed description are provided by way of explanation of the invention and not meant as a limitation of the invention. This invention thus includes any modifications and variations of the following examples as come within the scope of the appended claims and their equivalents. 
   The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. 
   As embodied in  FIG. 1 , a fiber optic connector  10  for connecting an optical fiber cable  12  to a receptacle (not shown), such as another connector, a connector adapter or other optical device, is provided. 
   With more particular reference to the Figures, connector  10  is attached to field fiber  14  of optical fiber cable  12 . Field fiber  14  typically has a glass diameter of about 125 μm. Typically, field fiber  14  also comprises one or more coatings disposed about the optical fiber. The one or more coatings may have various diameters, including diameters from about 245 μm to 900 μm for a buffered optical fiber, without departing from the scope of the present invention. Connector  10  includes connector housing  16 , ferrule  18 , ferrule holder  20 , spring element retainer  22 , spring element  24 , splice members  26 ,  28 , and cam member  30 . 
   As shown in greater detail in  FIGS. 2 and 3 , connector housing  16  has an inner surface  32  defining cavity  34  which extends longitudinally within housing  16 . Housing  16  further includes a forward opening  36  in communication with cavity  34  and a rearward opening  38  also in communication with cavity  34 . Rearward opening  38  is configured to receive ferrule holder  20  ( FIG. 1 ). Inner surface  32  of cavity  34  further defines a spring element seat  40 , the forward face  42  thereof providing a surface against which spring element  24  ( FIG. 1 ) may abut. Spring element seat  40  is generally located proximate to rearward opening  38 . The rearward face  44  of spring element seat  40  serves as a positive stop to limit the forward movement of ferrule holder  20  into housing cavity  34 . Inner surface  32  includes key  46  extending into cavity  34  at rearward opening  38 . Key  46  may be more clearly seen in  FIG. 2  showing a view of housing  16  looking forward toward forward opening  36  from rearward opening  38 . Preferably key  46  extends between the rearward face  44  of spring element seat  40  and opening  38 . Preferably, that portion of cavity  34  which extends forward of spring element seat  40  to forward opening  36  has a circular cross section in a plane orthagonal to longitudinal axis  48 , as best shown in  FIG. 2 . Preferably, that portion of cavity  34  which extends rearward of spring element seat  40  to rearward opening  38  has a cross sectional shape in a plane orthogonal to longitudinal axis  48  which is adapted to receive the cross sectional shape of at least a portion of ferrule holder  20 . Preferably, that portion of cavity  34  which extends rearward of spring element seat  40  to rearward opening  38  has a polygonal cross section in a plane orthagonal with longitudinal axis  48  of housing  16 . 
   Housing  16  also includes latching arm  50  and, as more clearly seen in  FIG. 4 , opposing latching lugs  52 ,  54  extending from housing  16  for latching connector  10  in place, such as, for example, an adapter adapted to receive connector  10 . Preferably, latching arm  50  is of a sufficient resiliency to allow latching arm  50  to be depressed and to return to its un-depressed position when latching arm  50  is released. Preferably, housing  16 , latching arm  50 , latching lugs  52 ,  54 , spring element seat  40  and key  46  are comprised of a suitable plastic material and are molded in one piece therefrom. 
   As illustrated in  FIGS. 5 and 6 , ferrule holder  20  extends longitudinally between first end  56  and second end  58 , and defines a longitudinally extending passageway  60 . Passageway  60  proximate first end  56  of ferrule holder  20  is sized to receive ferrule  18 , which may be made of any suitable, wear-resistant material such as ceramic, glass, metal, glass-reinforced epoxy or a polymer plastic. Ferrule  18 , shown in  FIG. 7 , has a first end  62  and a second end  64  and defines bore  66  extending axially therethrough. Optical fiber stub  68  is disposed in bore  66  such that second end  69  of optical fiber stub  68  extends beyond second end  64  of ferrule  18 . Preferably, second end  69  of optical fiber stub  18  extends at least about 5 mm beyond second end  64  of ferrule  18 ; more preferably at least about 10 mm. Optical fiber stub  68  is preferably secured in bore  66  with an adhesive such as an epoxy adhesive. The second end  69  of optical fiber stub  68  is preferably cleaved with a good finish, the cleave angle being preferably less than about one degree. The first end  69  of optical fiber stub  68  is preferably polished to facilitate optical transmission therethrough. 
   Returning to  FIG. 6 , ferrule holder  20  further defines cavity  70  in communication with passageway  60  to accommodate splice members  26  and  28  ( FIG. 1 ). Ferrule holder  20  includes a shoulder  72 , or stop, on outside surface  74  of ferrule holder  20  which is configured to be received into rearward opening  38  of connector housing  16 . A groove  76  extending longitudinally along at least a portion of stop  72  (more clearly seen in  FIG. 8 ) is configured to slidably engage with key  46  to provide for the correct orientation of ferrule holder  20  within housing  16 . Preferably, ferrule holder  20  also defines view port  78  extending from outside surface  72  into cavity  70  proximate the location of the mechanical abutment between stub fiber  68  and field fiber  14 . During operation of connector  10 , field fiber  14  and stub fiber  68  are abutted proximate view port  78  and a visible light, such as that from a HeNe laser or an LED, for example, is guided through at least one of the field fiber  14  or stub fiber  68 . If an incorrect abutment is obtained, light guided by optical fiber stub  68  or field fiber  14  will be scattered at the opposing end face and will be visible through view port  78 . When an acceptable abutment, or splice, is obtained, the light will be substantially guided between optical fiber stub  68  and field fiber  14 , with little scattering at the abutment thereof, and light from the laser or LED will no longer be visible through view port  78 . Therefore, view port  78  provides a visual indication of an acceptable mechanical splice (abutment) between the optical fiber stub  68  and the field fiber  14 . If the splice is unacceptable, the laser or LED light will not be visible through view port  78 . View port  78  may also be used as an access point for injecting an optical coupling material or refractive index matching gel into cavity  70  to improve the optical coupling between the optical fiber stub  48  and field fiber  14 . 
   Ferrule holder  20  also includes a slot, or window  80  extending between outside surface  74  and cavity  70  to accommodate a portion of lower splice component  28 . Window  80  is generally located opposite view port  78 . Second end  58  of ferrule holder  20  is adapted to receive a lead in tube  84 , illustrated in  FIGS. 9–12 , for guiding field fiber  14  into cavity  70  between splice members  26 ,  28 . Preferably, inside surface  86  of cavity  70  defines an axial groove  88  for receiving key  90  located on outside surface  92  of lead in tube  84 . When lead in tube  84  is inserted into second end  58  of ferrule holder  20 , groove  88  slidably engages with key  90  to prevent rotation of lead in tube  84  within ferrule holder  20 . Lead in tube  84  defines a passageway  94  ( FIGS. 11 and 12 ) extending axially between a first end  96  and a second end  98  of lead in tube  84  for accommodating field fiber  14 . Lead in tube  84  may be secured within ferrule holder  20  with an adhesive, such as, for example, an epoxy adhesive. Alternatively, lead in tube  84  could be press fit within ferrule holder  20 , or lead in tube  84  may be secured within ferrule holder  20  by cooperative retaining elements similar to those shown in  FIGS. 21–23  and described infra. Preferably, second end  98  of passageway  94  is sized to accommodate a crimp tube  132   FIG. 1 ). Preferably, a portion of passageway  94  proximate first end  96  has a generally conical shape for guiding field fiber  14  through opening  100  at first end  96  of lead in tube  84 . 
   Splice members  26  and  28  are inserted into cavity  70  of ferrule holder  20  through second end  58  proximate view port  78  and window  80 . First splice member  26  is generally adjacent view port  78 , while second splice member  28  is generally adjacent window  80 . As best depicted by  FIG. 13 , first splice member  26  is configured with a flat face  102  opposing second splice member  28 . Second splice member  28  comprises a projection, or keel portion  104  which protrudes through window  80  when splice member  28  is inserted into cavity  70  of ferrule holder  20 . A channel  81  extending from second end  58  of ferrule holder  20  to window  80  and shown in  FIGS. 5 and 6  guides keel portion  104  to window  80 , thereby facilitating the insertion of second splice member  28  into cavity  70  through second end  58 , and the further insertion of keel  104  through window  80 . On side  106  opposite keel portion  104  and opposing first splice component  26 , second splice member  28  includes a groove  108  extending longitudinally along the length of second splice member  28 . Although groove  108  as shown in  FIG. 13  is generally V-shaped, groove  108  could be any other shape that supports optical fiber stub  68 , such as, for example, a U-shaped groove. Alternatively, groove  108  could be formed in the opposing face of first splice component  26  and a flat face could be formed on the opposing face of second splice component  28 . Splice members  26 ,  28  are prevented from moving forward within cavity  70  in ferrule holder  20  by shoulder  110  adjacent the point where cavity  70  is in communication with passageway  60 . When ferrule  18  containing optical fiber stub  68  is positioned within first end  56  of ferrule holder  20 , the end of optical fiber stub  68  projecting from ferrule  18  is received by groove  108  and lies between first and second splice members  26  and  28  at a generally intermediate position. When lead in tube  84  is inserted in second end  58  of ferrule holder  20 , splice members  26 ,  28  are prevented from moving rearward within cavity  70  by the presence of lead in tube  84 . Thus, splice members  26  and  28  are generally prevented from axial movement within cavity  70  by shoulder  110  and lead in tube  84 . 
   Cam member  30  is mounted about ferrule holder  20  in an initial position generally proximate splice members  26 ,  28  as shown in  FIG. 9 . As illustrated in  FIGS. 15–17 , cam member  30  defines passageway  112  extending longitudinally between first end  118  and second end  120  that is sized to receive and therefore be mounted upon ferrule holder  20 . In order to actuate splice members  26 ,  28 , a portion of passageway  112  defined by cam member  30  is preferably noncircular and comprises a major axis  114  and a minor axis  116  as illustrated in  FIG. 15 . As best shown in  FIG. 16 , the portion of cam member  30  extending forward of shoulder  121  to end  118  is noncircular and defines major axis  114  and minor axis  116 . That portion of cam member  30  extending rearward of shoulder  121  to end  120  is generally circular and facilitates engagement of cam member  30  with ferrule holder  20 . Thus, shoulder  121  denotes the transition from the circular portion of passageway  112  and the noncircular portion of passageway  112 . As shown by  FIG. 16  and as evidenced by the thinner sidewall immediately adjacent the major axis  114  of cam member  30  at end  118 , the portions of passageway  112  adjacent major axis  114  have a smaller radius than the radius of those portions of passageway  112  immediately adjacent minor axis  116 . Moreover, passageway  112  is defined by cam member  30  such that the smaller radius of passageway  112  immediately adjacent major axis  114  transitions smoothly into the larger radius of passageway  112  immediately adjacent minor axis  116 . Preferably, cam member  30  also includes an outside surface at end  120  adapted to cooperate with a tool (not shown) for rotating cam member  30  about ferrule holder  20 . In the advantageous embodiment depicted in  FIGS. 15–17 , cam member  30  preferably comprises a first and second end  118 ,  120  separated by a barrel  122 . The outside surface of cam member  30  at second end  120  may be formed as a polygon such that the outside surface of end  120  may cooperatively engage with a tool, such as a wrench, for example, for rotating cam member  30  about ferrule holder  20 . However, it should be understood that the outside surface of end  120  may take on other shapes, such as a notched circular shape, which may cooperate with a complementary engaging surface or surfaces of an actuating tool. First end  118  is preferably formed to a shape and size which corresponds to the shape and size of the rearward portion of housing  16 . Cam member  30  preferably includes an indicator element, such as groove  123  best shown in  FIG. 17  at end  120 , to indicate the rotational position of cam member  30 , and thus the condition of splice members  26 ,  28  (i.e. actuated or un-actuated). For example, if visual indicator  123  is aligned with latch  50 , splice members  26 ,  28  are actuated. 
   As first illustrated in  FIG. 19 , cam member  30  of this advantageous embodiment is mounted upon ferrule holder  20  such that the noncircular portion of passageway  112  is generally disposed within ferrule holder  20  and exposed keel portion  104  of second splice member  28  is aligned with major axis  114  of passageway  112 . As a result, cam member  30  can be readily mounted on ferrule holder  20  while splice members  26  and  28  remain un-actuated. As next shown in  FIG. 20 , once cam member  30  has been mounted upon ferrule holder  20 , however, cam member  30  can be rotated relative to ferrule holder  20  from the first un-actuated position to a second actuated position so as to move the exposed keel portion  104  of second splice member  28  from a position along major axis  114  of passageway  112  to a position along minor axis  116  of passageway  112 . Due to the smaller dimensions of passageway  112  along minor axis  116 , cam member  30  operably contacts exposed keel portion  104  of second splice member  28  following rotation of cam member  30  relative to ferrule holder  20 . As a result of this contact, cam member  30  actuates splice members  26 ,  28 , such as by urging the splice members  26 ,  28  toward one another, so as to mechanically splice optical fiber stub  68  and field fiber  14  therebetween. 
   As best shown in  FIGS. 15 and 16 , cam member  30  of one advantageous embodiment of the present invention includes an inwardly extending projection  124 . While the inwardly extending projection  124  is adjacent one end of cam member  30  in the illustrated embodiment, the inwardly extending projection  124  can be positioned at other points along the lengthwise extending passageway  112 , if so desired. As shown in  FIG. 8 , the outer surface  72  of ferrule holder  20  of this advantageous embodiment also preferably defines a groove  126  for receiving the inwardly extending projection  124 . By confining the inwardly extending projection  124  within groove  126 , ferrule holder  20  can guide cam member  30  as cam member  30  is initially mounted upon ferrule holder  20 , i.e. slid lengthwise relative to ferrule holder  20 , as cam member  30  is subsequently rotated relative to ferrule holder  20  from the first, un-actuated position to the second, actuated position. Preferably, cam member  30  is formed from a transparent or translucent material such that light which may emit from view port  78  when testing connector  10  for proper abutment (splice quality) of stub fiber  68  and field fiber  14  will be visible through cam member  30 . 
   In the illustrated embodiment, the groove  126  defined by ferrule holder  20  is generally L-shaped. As such, groove  126  includes a first section  128  that extends lengthwise along a portion of ferrule holder  20  from the second end  58  of ferrule holder  20  to a medial portion of ferrule holder  20 . In addition, groove  126  includes a second section  130  that extends circumferentially about a portion, such as one-quarter, of ferrule holder  20 . As such, the inwardly extending projection  124  of cam member  30  is moved through the first section  128  of groove  126  as cam member  30  is slid lengthwise relative to ferrule holder  20  as cam member  30  is mounted upon ferrule holder  20 . Thereafter, the inwardly extending projection  124  of cam member  30  is moved through the second section  130  of groove  126  as cam member  30  is rotated relative to ferrule holder  20 . First and second sections  128 ,  130  of groove  126  of this embodiment are preferably orthogonal and intersect in the medial portion of ferrule holder  20  to permit cam member  30  to be rotated relative to ferrule holder  20  once cam member  30  has been fully mounted upon ferrule holder  20 . As best illustrated by the detailed view in  FIG. 18 , second section  130  of groove  126  also includes ridge  131  extending across the width of second section  130  for retaining cam member  30  in place after cam  30  has been rotated relative to ferrule holder  20  to the second, actuated position. As inwardly extending projection  124  is moved along second section  130  of groove  126 , inwardly extending projection  124  is “snapped” over ridge  131 , thereby interferingly restraining cam member  30  from being inadvertently removed from ferrule holder  20 . 
   As described supra, cam member  30  is in the first un-actuated position as cam member  30  is mounted upon ferrule holder  20  by moving the inwardly extending projection  124  through the first section  128  of groove  126 . As also described supra, cam member  30  transitions from the first, un-actuated position to the second, actuated position as cam member  30  is rotated relative to ferrule holder  20  by moving the inwardly extending projection  124  through the second section  130  of groove  126 . In the embodiment in which passageway  112  defined by cam member  30  includes a major axis  114  and a minor axis  116 , cam member  30  and ferrule holder  20  are preferably designed such that exposed keel portion  104  of second splice member  28  is aligned with major axis  114  of passageway  112  of cam member  30  as inwardly extending projection  124  of cam member  30  is moved through first section  128  of groove  126 . Correspondingly, cam member  30  and ferrule holder  20  of this advantageous embodiment are also preferably designed such that the exposed keel portion  104  of second splice member  28  is moved along the inside surface of cam member  30  from alignment with the major axis  114  of passageway  112  to alignment with the minor axis  116  of passageway  112  as the inwardly extending projection  124  is moved along through the second section  130  of groove  126 . By engaging exposed keel portion  104  of second splice member  28  with the inside surface of cam member  30  along the minor axis  116  of passageway  112 , splice components  26 ,  28  are actuated, such as by urging first and second splice members  26 ,  28  toward one another, so as to mechanically splice optical fiber stub  68  and field fiber  14  as described above. 
   By confining the inwardly extending projection  124  of cam member  30  to the generally L-shaped groove  126 , the fiber optic connector  10  of this advantageous embodiment of the present invention insures that cam member  30  is fully mounted upon ferrule holder  20  prior to actuating splice members  26 ,  28  by rotating cam member  30  relative to ferrule holder  20 , thereby providing complete or full actuation of splice members  26 ,  28 . In addition, fiber optic connector  10  of this advantageous embodiment prevents cam member  30  from being removed from ferrule holder  20  without first being moved to an un-actuated position by rotating cam member  30  in the opposite direction relative to ferrule holder  20  so as to move the inwardly extending projection  124  from second section  130  of groove  126  in which splice members  26 ,  28  are actuated to first section  128  of groove  126  in which splice members  26 ,  28  are un-actuated. Ridge  131 , in cooperation with inwardly extending projection  124 , prevents inadvertent removal of cam member  30 . Thus, fiber optic connector  10  of this advantageous embodiment prevents inadvertent damage to the components of the fiber optic connector which could otherwise possibly be incurred by removing cam member  30  from ferrule holder  20  while in the actuated position. Once splice members  26 ,  28  have been actuated, such as by mounting cam member  30  upon the ferrule holder  20  and thereafter rotating cam member  30  relative to ferrule holder  20  the remaining components of the fiber optical connector may be assembled. 
   As shown in  FIGS. 1 and 14 , fiber optic connector  10  includes crimp tube  132  which is mounted within the rearward end of lead in tube  84 . Crimp tube  132  may be formed from any material suitable for the purpose, including copper, stainless steel or brass. To insert field fiber  14  into crimp tube  132 , a portion of coating which may surround field fiber  14  is removed to expose the bare glass of field fiber  14 . Enough coating material is removed from field fiber  14  such that field fiber  14  may extend within connector  10  to abut with optical fiber stub  68  between splice members  26  and  28 . When field fiber  14  has been inserted into crimp tube  132 , the coated portion of field fiber  14  may be securely engaged by crimp tube  132  by crimping crimp tube  132  about the coated portion of field fiber  14 . 
   Also as shown in  FIGS. 1 and 14 , fiber optic connector  10  may include annular crimp band  134  which is mounted upon the rearward end  58  of ferrule holder  20  proximate cam member  30 . Crimp band  134  may be formed from any material suitable for the purpose, including copper, stainless steel or brass. In embodiments in which field fiber  14  is associated with strength members  136 , such as the filamentary strength members of fiber optic cable  12  as shown in  FIG. 1 , strength members  136  can be positioned between crimp band  134  and ferrule holder  20  such that strength members  136  can be securely engaged by crimping crimp band  134  about ferrule holder  20  as known by those skilled in the art. The strength members of fiber optical cable  12  may comprise, for example, an aramid filament or yarn. Thereafter, boot  138  which has previously been mounted on field fiber  14  can be mounted over crimp band  134  so as to provide strain relief to field fiber  14 . 
   As illustrated in  FIG. 1 and 14 , ferrule holder  20  is inserted into the rearward opening  38  of housing  16  such that first end  56  of ferrule holder  20 , and ferrule  18 , extend forward beyond spring element seat  40 . Spring element  24  is positioned over first end  56  of ferrule holder  20  and compressed between the forward face  42  of spring element seat  40  and spring element retainer  22  to a predetermined spring force, spring element retainer  22  being engaged with first end  56  of ferrule holder  20 . Thus, ferrule holder  20 , and ferrule  18 , are allowed to translate axially, or piston, within housing  16 . Spring element retainer  22  may be engaged with first end  56  of ferrule holder  20  by any suitable method known in the art. As best shown in  FIGS. 6 and 8 , ferrule holder  20  is formed with screw threads  140  located proximate end  56 . As best depicted in  FIG. 21 , corresponding screw threads on the inside surface of spring element retainer  22  are configured to engage with screw threads  140  on ferrule holder  20  and allow spring element retainer  22  to be removably fastened to end  56  of ferrule holder  20  by screwing spring element retainer  22  to end  56  of ferrule holder  20 . Alternatively, end  56  and spring element retainer  22  may be designed to allow spring element retainer  22  to be snap fit to ferrule holder  20  at end  56 . For example, as shown in  FIGS. 22 and 23 , a groove  139  ( FIG. 23 ) may be formed about a circumference of ferrule holder  20  proximate end  56 . A corresponding ridge  129  ( FIG. 22 ) formed about the inside circumference of spring retainer  22  is configured to engage with groove  139 . Spring element retainer  22  may then be snapped into place over end  56  of ferrule holder  20 . Alternatively, a groove may be formed about the inside circumference of spring element retainer  22  and a corresponding ridge nay be formed about ferrule holder  20  proximate end  56 . 
   Spring element  24  is configured such that spring element  24  is fully compressed before stop  72  of ferrule holder  20  is completely removed from housing  16 , thus limiting the longitudinal movement of ferrule holder  20  within housing  16 . When connector  10  has been assembled, spring element  24  preferably exerts a spring force between about 1 and 1.5 lbs against spring retainer  22 , more preferably between about 1.1 and 1.4 lbs. 
   According to one embodiment of the invention, and as broadly shown in  FIG. 24 , a trigger member  142  is removably attached to cam member  30 . Trigger member  142  includes a first element  144  and a second element  146 . Trigger member  142  is removably attached to cam member  30  via first element  144 . First element  144  preferably defines a longitudinally-extending opening  148  configured for receiving cam barrel  122  ( FIG. 17 ) and permitting trigger member  142  to be snapped over cam member  30  to thereby attach trigger member  142  to cam member  30 . More particularly, opening  148  is configured for permitting trigger member  142  to be radially snapped onto cam barrel  122 . Accordingly, a slot  150  is provided in first element  144 . Slot  150  should be wide enough to allow barrel  122  to pass though the slot. First member  144  may thus be substantially C-shaped to snugly fit on barrel  122  of cam member  30 . Although not illustrated, if barrel  122  was a shape other than cylindrical (e.g., square, rectangular, etc., in cross-section), then trigger member  142  would have a corresponding configuration. 
   Mating attachment elements are provided respectively on cam member  30  and first element  144  for releasably attaching and axially securing first element  144  to the housing. Preferably, the mating attachment elements comprise snap members  152  on trigger member  142  and grooves  153  in cam member  30 . The locations of snap members  152  and grooves  153  could be switched. Snap members  152  may include chamfered edges  154  to allow trigger member  142  to be more easily snapped over cam member  30 . The mating attachment elements may alternately have other complimentary shapes, such as ridges, dimples, arcs, spherical sections, etc., within the scope of the invention spring retainer  22  is configured to engage with groove  139 . Spring element retainer  22  may then be snapped into place over end  56  of ferrule holder  20 . Alternatively, a groove may be formed about the inside circumference of spring element retainer  22  and a corresponding ridge nay be formed about ferrule holder  20  proximate end  56 . 
   Spring element  24  is configured such that spring element  24  is fully compressed before stop  72  of ferrule holder  20  is completely removed from housing  16 , thus limiting the longitudinal movement of ferrule holder  20  within housing  16 . When connector  10  has been assembled, spring element  24  preferably exerts a spring force between about 1 and 1.5 lbs against spring retainer  22 , more preferably between about 1.1 and 1.4 lbs. 
   According to one embodiment of the invention, and as broadly shown in  FIG. 24 , a trigger member  142  is removably attached to cam member  30 . Trigger member  142  includes a first element  144  and a second element  146 . Trigger member  142  is removably attached to cam member  30  via first element  144 . First element  144  preferably defines a longitudinally-extending opening  148  configured for receiving cam barrel  122  ( FIG. 17 ) and permitting trigger member  142  to be snapped over cam member  30  to thereby attach trigger member  142  to cam member  30 . More particularly, opening  148  is configured for permitting trigger member  142  to be radially snapped onto cam barrel  122 . Accordingly, a slot  150  is provided in first element  144 . Slot  150  should be wide enough to allow barrel  122  to pass though the slot. First member  144  may thus be substantially C-shaped to snugly fit on barrel  122  of cam member  30 . Although not illustrated, if barrel  122  was a shape other than cylindrical (e.g., square, rectangular, etc., in cross-section), then trigger member  142  would have a corresponding configuration. 
   Mating attachment elements are provided respectively on cam member  30  and first element  144  for releasably attaching and axially securing first element  144  to the housing. Preferably, the mating attachment elements comprise snap members  152  on trigger member  142  and grooves  153  in cam member  30 . The locations of snap members  152  and grooves  153  could be switched. Snap members  152  may include chamfered edges  154  to allow trigger member  142  to be more easily snapped over cam member  30 . The mating attachment elements may alternately have other complimentary shapes, such as ridges, dimples, arcs, spherical sections, etc., within the scope of the invention. 
   Mating alignment elements are also provided for rotationally securing first element  144  relative to cam member  30 . The alignment elements may comprise any variety of non-circumferential surfaces that interferingly prevent substantial rotation of trigger member  30  relative to cam member  30 . The alignment elements may comprise for example, planar surfaces  156  and  158 , as shown in  FIGS. 17 and 24 , that contact each other when trigger member  142  is attached to cam member  30 . As shown, alignment elements  158  are on cam member  30  and alignment elements  156  are on first element  144  of trigger member  30 . Alternately, the alignment elements may comprise planar surfaces  160  at the ends of snap members  152  and corresponding planar surfaces at the bottom of grooves  153 . Also, the alignment elements could have shapes other than planar, such as oblong, oval, irregular, etc., and be within the scope of the invention. When the alignment elements are aligned, second member  146  is also aligned with latch  50  (unless trigger member  142  has been installed upside down). If desired, the attachment elements and alignment elements could be configured so that inadvertent misaligned attachment of trigger member  142  to cam member  30  is difficult or impossible, for example by making the attachment or alignment elements non-symmetrical or irregular in some way. 
   Second element  146  of trigger member  142  has a proximal end  162  attached to first element  144  and a distal end  164  extending from the first element. Second element  146  provides at least two functions. First, second element  146  is pivotable as is latch  50  and engages the latch to pivot the latch downward. The engagement moves distal end  166  ( FIG. 3 ) of latch  50  downward to selectably release housing  16  from a receptacle. Second element  146  has a contoured surface  170  for contacting tip  172  ( FIG. 3 ) of latch  50  and assisting in pivoting latch  50  downward when second element  146  is depressed. Second element  146  thus comprises a trigger element which releases latch  50  when the trigger element is depressed. The second function provided is that if cable  12  is pulled backwardly, second element  146  reduces the possibility of latch  50  snagging on other cables, corners, or other fixtures along the routing path, as the second element extends at an acute angle toward and beyond tip  172  of latch  50 . Preferably first and second elements  144 ,  146  are comprised of a suitable plastic material and are molded in one piece therefrom. 
   When ferrule holder  20  has been assembled into housing  16  and cam member  30  has been fully mounted onto ferrule holder  20 , trigger member  142  may preferably be mounted onto cam member  30  such that snap members  152  may engage with corresponding recesses, or grooves  153  on cam member  30 . The engagement of snap members  152  with grooves  153  prevent trigger member  142  from rotating on cam member  30  and maintain second trigger member  144  in alignment with latching arm  50  when cam member  30  has been rotated into the second, actuated position. 
   Field assembly of the optical fiber connector according to the present invention comprises inserting a second optical fiber, such as field fiber  14  into the rearward opening of lead in tube  84  until field fiber  14  is abutted to optical fiber stub  68 . Preferably, the end of field fiber  14  which is inserted into connector  10  is cleaved with a good end face, preferably with a cleave angle less than about 1 degree, to facilitate transmission therethrough. A light, such as a visible laser light or light from an LED, may be injected in the first end of optical fiber stub  68 , whereupon cam member  30  is turned in a direction which urges splice members  26  and  28  together, thereby securing the abutting ends of optical fiber stub  68  and field fiber  14  in a position that facilitates transmission therethrough. For example, a tool (not shown) may be used to engage with a portion of cam member  30  adapted to engage with the tool, and cam member  30  then rotated to urge splice members  26  and  28  together. View port  78  may then be observed for an indication of the quality of the splice between the optical fiber stub  68  and field fiber  14 , as described supra. When cam member  30  has been rotated and a good splice indicated by the absence of light from view port  78 , trigger member  142  may then be snapped onto cam member  30  as previously described. 
   As described above, an optical fiber connector  10  of the present invention can be readily fabricated. In particular, the ferrule can be formed and the optical fiber stub  68  disposed therein in a factory setting such that the first end of the optical fiber stub  68  can be polished while disposed in the first end of ferrule  18 . Thereafter, an end portion of a second optical fiber, such as field fiber  14 , can be inserted through lead in tube  84  into cavity  70  between splice members  26 ,  28 , whereupon cam member  30  may be rotated to activate splice members  26 ,  28 . When activated, splice members  26  and  28  secure the second end  69  of optical fiber stub  68  and field fiber  14  to facilitate transmission therethrough. Once optical fiber stub  68  and field fiber  14  have been secured by splice members  26 ,  28 , the various remaining components of connector  10 , such as crimp band  134  and boot  138 , may be assembled onto fiber optic connector  10 . 
   It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.