Abstract:
In one aspect, a connector is described. The connector comprises a plurality of optical fibers, at least two MT fiber optic connectors, communicatively coupled to one another utilizing the plurality of optical fibers, each MT fiber optic connector comprises a mating end. The connector further comprises a connector body formed around the MT fiber optic connectors and the plurality of optical fibers, said mating ends of the MT fiber optic connectors accessible from opposite ends of the connector body.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to fiber optic interconnections, and more specifically, to methods and apparatus for connecting fiber optic cables in a locked and environmentally sealed manner. 
         [0002]    Fiber optic communication systems can transmit data at higher rates than systems utilizing electrical wires. Fiber optic communication systems can also be made lighter than systems utilizing electrical wires, which is a benefit in many applications including aerospace applications. Also, by using fiber to transmit data, radiated emissions associated with using copper as the transmission vehicle are avoided. 
         [0003]    Fiber optic communication systems utilize pulses of light to send information across strands of transparent material. These strands of transparent material are referred to as fiber optics. In a typical application, an optical transmitter includes a laser that emits light. The intensity of the light is varied in accordance with the information to be sent. The light is focused on an end of an optical fiber so that the light is transmitted along the fiber. 
         [0004]    At the opposite end of the optical fiber, the light is directed onto a photodetector, which transforms the light into an electrical signal. The electrical signal also varies in relation to the information being sent. Typically, multiple fibers are aligned in parallel so a greater quantity of information can be sent along a single cable at once, and so that information can be sent in both directions simultaneously. The optical transmitter and photodetector are often combined in a single device, a transceiver. 
         [0005]    When interconnecting fiber optic cables, each individual optical fiber within a cable must be precisely aligned with the mating optical fibers within the other cable. Each optical fiber must also be butted against one another with essentially no gaps. Even a slight misalignment or gap can cause an appreciable loss of light transmitted along the fibers and a degradation of the signal. Devices referred to as connectors can be engaged with mating connectors on other cables, or with mating features on transceivers, to align the fibers with the required precision and hold the fibers in contact with one another. One type of known fiber optic connector is an MT type, which includes a connector housing with a front end and a ferrule movably mounted in the housing. 
         [0006]    In certain applications, including military applications, protecting the electronics on the inside of a housing or chassis from the environment is desired. 
         [0007]    The prior art includes a connector which has an internal latching structure, and in particular, is used with fiber optic connectors. Two mating connectors of this type can be interconnected, and a fiber optic connection can be provided in a sealed environment, yet the mating connectors can be easily disconnected. This connector includes an inner fiber optic connector assembly that is passed through an outer housing portion and a rotatable collar portion. Once the inner fiber connector assembly is passed through the outer housing portion, the inner fiber connector protrudes from a first side of the sealed connector, and a fiber optic cable extends from the second side of the sealed connector. 
         [0008]    The connector described above does not describe an environmentally sealed connector. Additionally, the connector described above cannot be mounted within an electronic package (i.e., a metal chassis). Furthermore, this connector assembly requires that a fiber optic cable be attached to an MT connector before assembled in the housing portion of the connector assembly. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0009]    In one aspect, a connector is provided. The connector comprises a plurality of optical fibers, at least two MT fiber optic connectors, communicatively coupled to one another utilizing the plurality of optical fibers, each MT fiber optic connector comprises a mating end. The connector further comprises a connector body formed around the MT fiber optic connectors and the plurality of optical fibers, said mating ends of the MT fiber optic connectors accessible from opposite ends of the connector body. 
         [0010]    In another aspect, a method of fabricating a fiber optic interconnection is provided. The method comprises communicatively coupling a first MT connector to a second MT connector, forming a connector body around the coupled MT connectors, such that mating portions of the MT connectors are accessible at opposite ends of the connector body, and inserting the connector body within a connector shell. 
         [0011]    In yet another aspect, a connector assembly is provided. The system comprises a plurality of optical fibers, at least two MT fiber optic connectors, communicatively coupled to one another utilizing the plurality of optical fibers, each MT fiber optic connector comprising a mating end, a connector body formed around the MT fiber optic connectors and the plurality of optical fibers, the mating ends of said MT fiber optic connectors accessible from opposite ends of said connector body, and a connector shell configured for insertion and retention of the connector body. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an illustration of an existing configuration of a transceiver, a first fiber optic cable, a female coupler, a male coupler, a second fiber optic cable, and a connector. 
           [0013]      FIG. 2  is an illustration of a transceiver, a fiber optic cable terminating at an MT plug, and a connector assembly. 
           [0014]      FIG. 3  is a rear perspective view of a connector assembly including a rear locking MT connector insert. 
           [0015]      FIG. 4  is a front perspective view of a connector assembly including a rear locking MT connector insert. 
           [0016]      FIG. 5  is an illustration of a connector assembly mounted on a chassis of an electronic package. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Methods and apparatus for connecting fiber optic cables are described. In one embodiment, the methods and apparatus provide a locking, environmentally sealed connection between fiber optic cables. 
         [0018]    Referring now to the drawings,  FIG. 1  shows an existing configuration of a transceiver  20 , a first fiber optic cable  22 , a female coupler  24  including an MT connector, a male coupler  26  including an MT connector, a second fiber optic cable  28 , and a connector  30 . Connector  30  includes a connector shell  32 , an MT connector insert  34 , and is manufactured with second fiber optic cable  28  extending from a rear of connector  30 . In order for information from transceiver  20  to reach connector  30 , first fiber optic cable  22  and second fiber optic cable  28  are mated using couplers  24  and  26 . It would be advantageous to find a method of mating a transceiver to a connector, such as connector  30 , without the size and weight issues that are encountered when using couplers  24  and  26 . 
         [0019]      FIG. 2  shows a transceiver  40 , a fiber optic cable  42  terminating at an MT plug  44 , and a connector assembly  46 . Connector assembly  46  includes a connector body  47  into which a rear locking MT connector  48  is placed. Connector body  47  is mounted within a connector shell  50 . Connector body  47  of connector assembly  46  also includes an MT connector insert  52  that extends from a front of connector body  47 . In a preferred embodiment, connector shell  50  is a MIL-C-38999 connector shell, commercially available from Amphenol Aerospace of Sidney, N.Y., and commonly used across the aerospace industry and in military applications when a sealed interface is desired within an electronic system. MT connector insert  52  includes a front MT connector  53 , rear locking MT connector  48 , and a plurality of optical fibers (not shown) communicatively coupling front MT connector  53  and rear locking MT connector  48 . Since connector assembly  46  includes an integrated rear locking MT connector  48 , communicatively coupled to front MT connector  53 , there is no need for couplers  24  and  26  as shown in  FIG. 1 , and further described below. 
         [0020]      FIG. 3  shows a rear perspective view of connector assembly  46  including rear locking MT connector  48 . Connector assembly  46  also includes connector shell  50 , front MT connector  53 , and a mounting flange  54 . Connector assembly  46  includes coupling fibers  56 , within connector body  47 , that communicatively couple MT connector inserts  48  and  52 . Connector body  47  is not shown in  FIGS. 3 and 4  for clarity, though, as described above, MT connector inserts  48  and  52  and coupling fibers  56  are embedded within connector body  47 . In the illustrated embodiment, three coupling fibers  56  communicatively couple MT connector insert  48  to corresponding positions within MT connector insert  52 . In another known embodiment (not shown), twelve fiber optic fibers communicatively couple MT connector insert  48  to corresponding positions within MT connector insert  52 . 
         [0021]      FIG. 4  shows a front perspective view of connector assembly  46  including rear locking MT connector insert  48 , front MT connector insert  52  and fiber optics  56  extending between the two, as shown in  FIG. 3 , and where like components are referenced with like reference numerals. 
         [0022]      FIG. 5  shows two embodiments of connector assembly  46  mounted on a chassis  58  (e.g. a housing) of an electronic package. As described above, connector shell  50  includes a mounting flange  54 . There are two common types of MIL-C-38999 connector shells, panel mount style and jam-nut style.  FIGS. 1 and 2  show a panel mount style of connector shell  50  having a plurality of openings  60  therethrough. To mount a panel mount style of connector shell  50  to chassis  58 , openings  60  are aligned with a like pattern of bores through chassis  58 .  FIGS. 3 and 4  show a jam-nut style of connector shell  50 . A jam-nut style of connector shell  50  includes mounting flange  54  and a nut  62 . To mount a jam-nut style of connector shell  50  to chassis  58 , nut  62  is removed from connector shell  50 , connector shell  50  is aligned with a properly sized opening within chassis  58 , and nut  62  is reapplied to connector shell  50 , such that chassis  58  is between mounting flange  54  and nut  62 , holding connector shell  50  to chassis  58 . 
         [0023]    When connector shell  50  is on chassis  58 , the rear of connector assembly  46  is environmentally sealed within chassis  58 . However, the front of connector shell  50 , which includes front MT connector  53 , is outside of sealed chassis  58 . Connector shell  50  and the corresponding connector that attaches to connector shell  50 , in combination with chassis  58 , provide an environmental seal surrounding MT connectors  48  and  53 , and the interconnections therebetween  56 . 
         [0024]    By eliminating the need for couplers  24  and  26  and integrating rear locking MT connector insert  52  within connector shell  50 , the space needed inside chassis  58  is reduced as compared to known fiber optic interconnections. Another benefit is increased signal integrity caused by the elimination of one extra connection. Also, product life is increased since 40%-70% of all electronic failures occur at interconnections. Furthermore, assembly time is reduced since there is one less connection to be made. 
         [0025]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.