Abstract:
Fiber optic interface devices ( 20, 320 ) for electronic devices ( 300 ) are disclosed. A plug-type fiber optic interface ( 20 ) has an axially moveable multi-fiber ferrule ( 100 ) that supports optical fibers ( 52 ) or a combination of optical fibers and gradient-index lenses ( 600 ). A resilient member ( 150 ) serves to provide the ferrule with forward-bias and rear-bias positions relative to a recessed front end ( 22 ) of a housing ( 21 ). A fiber optic interface assembly ( 570 ) that includes mated plug and receptacle fiber optic interface devices ( 20, 320 ) is also disclosed.

Description:
CLAIM OF PRIORITY 
       [0001]    This is a divisional of U.S. patent application Ser. No. 13/050,747 filed on Mar. 17, 2011, which claims the benefit of priority of U.S. Provisional Application Ser. No. 61/315,417, filed on Mar. 19, 2010, the content of which is relied upon and incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present disclosure relates generally to fiber optic interface devices, and in particular relates to multi-fiber fiber optic interface devices for use with electronic devices. 
       BACKGROUND 
       [0003]    Optical fiber is increasingly being used for a variety of applications, including but not limited to broadband voice, video, and data transmission. As consumer devices are steadily using more bandwidth, interface devices for these devices will likely move away from electrical connections and toward using optical connections for increased bandwidth. Generally speaking, conventional fiber optic interface devices used for telecommunication networks and the like are not suitable for consumer electronic devices. 
         [0004]    For instance, conventional fiber optic interface devices are relatively large compared with the consumer electronic devices and their interfaces. Additionally, conventional fiber optic interface devices are deployed with great care into relatively clean environments and/or cleaned by the craft before connecting to the device interface. Further, even though fiber optic interface devices are reconfigurable (i.e., suitable for mating/unmating), they are not intended for a relatively large number of mating cycles. Instead, conventional fiber optic interface devices are high-precision interface devices designed for reducing insertion loss between mating interface devices in the optical network. 
         [0005]    On the other hand, the consumer electronic devices are expected to have a relatively large number of mating/unmating cycles during ordinary operation. The consumer electronic devices will be operated in a multitude of environments where dirt, dust, and other debris is encountered on a regular basis. Further, consumer electronic devices typically have size and space constraints for making connections. Consequently, there is an unresolved need for fiber optic interface devices suitable for consumer electronic devices. 
       SUMMARY 
       [0006]    An aspect of the disclosure is a fiber optic interface device for connecting at least one optical fiber of an optical fiber cable. The fiber optic interface device includes a housing having a central axis, a front end, and an interior having a ferrule guide member disposed therein and attached to the housing. The fiber optic interface device also includes a ferrule having a central axis, and front and rear ends. The ferrule is configured to support the at least one optical fiber having an optical fiber end substantially at the ferrule front end. The ferrule is moveably supported by the ferrule guide member, with the ferrule axis being aligned with (e.g., coaxial with) the housing central axis. A resilient member is disposed within the housing interior and is operatively arranged therein to forward-bias the ferrule toward the housing front end when the fiber optic interface device is not mated (i.e., is not interfaced) with another fiber optic interface device. 
         [0007]    Another aspect of the disclosure is a fiber optic interface assembly that includes the fiber optic interface device as described immediately above, and a receptacle matingly engaged with the fiber optic interface device. The receptacle acts to place the fiber optic interface device in a rear-biased position wherein the ferrule axially moves relative to a recessed front end of the housing. 
         [0008]    Another aspect of the disclosure is a fiber optic interface device for connecting transmit and receive optical fibers having respective ends. The device includes a housing having a central axis, a front end, an exterior surface and an interior having a ferrule guide member disposed therein and attached to the housing (e.g., fixed thereto). The device also includes a ferrule having a central axis, and front and rear ends. The ferrule is configured to support the transmit and receive optical fibers and respective transmit and receive gradient-index (GRIN) lens elements having front and rear surfaces. The transmit and receive optical fiber ends are arranged adjacent respective transmit and receive GRIN lens rear surfaces while the transmit and receive GRIN lens front surfaces are arranged at or adjacent the ferrule front end. The ferrule is moveably supported by the ferrule guide member so that the ferrule can move axially, with the ferrule axis being aligned with (e.g., coaxial with) the housing central axis. The device also includes a resilient member disposed within the housing interior and configured to forward-bias the ferrule toward the housing front end when the fiber optic interface device is unmated. 
         [0009]    Another aspect of the disclosure is a fiber optic interface assembly that includes the fiber optic interface device as described immediately above, and a receptacle matingly engaged with the fiber optic interface device. The receptacle acts to place the fiber optic interface device in a rear-biased position wherein the ferrule axially moves relative to a recessed front end of the housing. 
         [0010]    It is to be understood that both the foregoing general description and the following detailed description present embodiments of the disclosure, and are intended to provide an overview or framework for understanding the nature and character of the disclosure as it is claimed. The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute part of this specification. The drawings illustrate various exemplary embodiments of the disclosure, and together with the description serve to explain the principles and operations of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  and  FIG. 2  are front elevated views of an example fiber optic cable assembly that employs an example fiber optic interface device in the form of a plug; 
           [0012]      FIG. 3  and  FIG. 4  are front and rear elevated cut-away views that illustrate details of the interior configuration of the plug of  FIG. 1  and  FIG. 2 , with  FIG. 4  illustrating laser processing of the optical fibers using a laser beam; 
           [0013]      FIG. 5  is similar to  FIG. 4 , but shows the plug ferrule in the rear-biased position due to an urging force on the plug ferrule in the axial direction and toward the rear end of the plug housing; 
           [0014]      FIG. 6  is a top-down view of an example electronic device and the fiber optic cable assembly next to the electronic device; 
           [0015]      FIG. 7A  is a close-up, top-down cut-away view of the plug adjacent the receptacle of the electronic device just prior to engaging the plug and receptacle; 
           [0016]      FIG. 7B  is similar to  FIG. 7A , but shows the plug matingly engaged with the receptacle of the electronic device; 
           [0017]      FIG. 8A  is a front-elevated view similar to  FIG. 2 , and  FIG. 8B  is a partial cut-away view that illustrates an example embodiment of a fiber optic cable assembly having a plug that includes gradient-index (GRIN) lenses; 
           [0018]      FIG. 9  is similar to  FIG. 7B  and illustrates an example embodiment of fiber optic interface assembly where the plug and receptacle include GRIN lenses; and 
           [0019]      FIG. 10  is a close-up view of the interface between the plug and receptacle showing the interfaced GRIN lenses of the plug and receptacle. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Reference is now made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, like or similar reference numerals are used throughout the drawings to refer to like or similar parts. Various modifications and alterations may be made to the following examples within the scope of the present disclosure, and aspects of the different examples may be mixed in different ways to achieve yet further examples. Accordingly, the true scope of the disclosure is to be understood from the entirety of the present disclosure, in view of but not limited to the embodiments described herein. 
         [0021]    In some of the Figures, Cartesian coordinates are shown for reference. Also, the terms “plug” and “receptacle” are used for the sake of distinguishing different parts of a fiber optic interface device assembly that includes two fiber optic interface devices having complementary geometries. Further, in some of the examples discussed below, the receptacle is part of an electronic device, and a plug is used to plug into the receptacle of the electronic device. 
         [0022]    In the discussion below, the term “electronic device” means a device that has either electronic or optical and electronic components and functionality, including a receptacle and associated hardware configured to receive, transmit or both transmit and receive optical signals and also communicate electrical power. 
         [0023]      FIG. 1  and  FIG. 2  are front elevated views of an example fiber optic cable assembly  10  that includes a fiber optic interface device  20  operably connected to a fiber optic cable  50 . In an example, fiber optic cable  50  carries at least one optical fiber  52 , e.g., two optical fibers, with one being a transmit fiber and one being a receive fiber for respectively carrying transmit and receive optical signals. Also in an example embodiment, fiber optical cable  50  carries at least one electrical wire  54 , e.g., two electrical wires (“black and red”) that can carry electrical power. In the example, where fiber optic cable  50  carries both at least one optical fiber  52  and at least one electrical wire  54 , fiber optic interface device  20  can be thought of as a hybrid electrical-optical (0-E) interface device.  FIG. 3  and  FIG. 4  are front and rear elevated cut-away views that illustrate details of the interior configuration of fiber optic interface device  20 . 
         [0024]    As fiber optic interface device  20  is configured to plug into a complementary fiber optic interface device, it is referred to hereinafter as plug  20 , and the complementary fiber optic interface device introduced and discussed below is referred to as receptacle  320 . 
         [0025]    With reference to  FIG. 1  through  FIG. 4 , plug  20  includes a housing  21  with a central axis A 0 , a front end  22 , a rear end  24  and sides  26  that constitute part of housing exterior surface  27 . Rear end  24  includes an opening  25 . A strain-relief member  30  is arranged at rear end  24  of housing  21  at opening  25  and serves to reduce the amount of strain on fiber optic cable  50  where the fiber optic cable connects to the housing. Plug  20  includes a central axis A 1  that is co-axial with housing central axis A 0 . 
         [0026]    Front end  22  of plug housing  21  includes a recess  36  that defines housing side extensions or prongs  38  that serve to provide alignment with a complementary receptacle  320  (introduced and discussed below in connection with  FIG. 6  and  FIGS. 7A and 7B ), to which plug  20  is configured to matingly engage. Recess  36  thus defines a recessed front end  22 R of housing  21  within recess  36 . 
         [0027]    Housing  21  defines an interior  40  that includes a front section  42  open at housing front end  22  and a rear section  44  (see  FIGS. 3 and 4 ). Front and rear interior sections  42  and  44  are generally defined by an internal wall  60  having front and rear surface  62  and  64 , and a central aperture  68  open to the front and rear interior sections. Rear interior section  44  includes interior sidewalls  45  and a floor  47 . Rear interior section  44  also includes a retention feature  70  disposed between interior wall  60  and housing rear end  24 . Retention feature  70  is connected to floor  47  of rear interior section  44  and includes a central aperture  72  sized to pass optical fibers  52  that pass into rear interior section  44  of housing  21  through the housing rear-end opening  25 . 
         [0028]    Plug  20  also includes a ferrule  100  arranged in housing interior  40 . In an example, ferrule  100  has an MT configuration. Ferrule  100  includes a front section  101  having a front end  102 , and a rear section  103  having a rear end  104 . Ferrule  100  also includes a top  105 . Ferrule  100  is arranged in housing interior  40  and within central aperture  68  of internal wall  60  so that ferrule front section  101  resides within front interior section  42  and ferrule rear section  103  resides within rear interior section  44 . Ferrule  100  has a central axis AF that is aligned with plug axis A 1  when the plug ferrule is arranged in housing interior  40 ; for example, the alignment can be essentially coaxial alignment, or it can be slightly offset alignment. 
         [0029]    The ferrule front and rear sections  101  and  103  are defined by a step  110 , with the rear section being wider than the front section. Ferrule  100  is loosely held within wall aperture  68  so that it can move axially within plug housing  21 . Ferrule step  110  engages the rear surface  64  of internal wall  60  to limit the forward movement of the ferrule  100 . In this sense, internal wall  60  serves as an example of a ferrule guide member configured to allow ferrule  100  to move axially within housing  21 . Other configurations for a ferrule guide member beyond the example of an internal wall  60  and aperture  68  can also be employed; for example, the wall can be attached to plug  20  by being monolithically formed to it, or wall  60  can be attached by sliding the wall into grooves, slots, latches, recesses, snap fit structure, or other suitable attachment attributes. Thus, in an example, a ferrule guide member is disposed within housing interior  40  and is attached (e.g., fixedly attached) to the housing. 
         [0030]    Plug  20  further includes a resilient member  150  having a front end  152  and a rear end  154 . In an example, resilient member  150  is operatively arranged within housing interior rear section  44  with the resilient member front end  152  at ferrule rear end  104  and the resilient member rear end  154  at retention feature  70 . Resilient member  150  has a spring force that serves to urge ferrule  100  to a forward-bias position when plug  20  is not engaged with a receptacle or is not otherwise intentionally being urged rearward. The forward-bias position is defined by the aforementioned ferrule step  110  contacting internal wall rear surface  64 , and places ferrule front end  102  substantially at recessed front end  22 R of plug housing  21 . 
         [0031]    Resilient member  150  is also configured to compress to allow for ferrule  100  to move axially rearward within plug housing  21  when the plug engages a receptacle or is otherwise urged rearward in the housing. In an example embodiment, resilient member  150  is a spring with an interior  156 , and optical fibers  52  travel through the spring interior to ferrule  100 . In an alternate example, retention feature  70  is not employed and one end of resilient member  150  resides against housing rear end  24  within rear interior section  44 . 
         [0032]    Ferrule  100  further includes waveguide bores  160  that extend from ferrule rear end  104  to ferrule front end  102  where the bores terminate at bore ends  162 . In one example, bores  160  are sized to support optical waveguides, e.g., optical fibers  52 . In an example, ferrule  100  includes two waveguide bores  160  configured to respectively accommodate two optical fibers  52 , which can be transmit and receive optical fibers. Optical fibers  52  have optical fiber ends  52 E that in one example terminate substantially at waveguide bore ends  162 , i.e., directly at the waveguide bore ends, or slightly extending from the waveguide bore ends, or slightly recessed in the waveguide bore ends. Optical fibers  52  are provided with some slack within rear interior section  44  of housing interior  40  to accommodate the axial movement of ferrule  100 . 
         [0033]    Ferrule  100  also includes an angled portion  170  adjacent ferrule front end  102  and ferrule top surface  105 . Angled portion  170  facilitates laser processing of optical fibers  52  using a laser beam LB to form optical fiber ends  52 E at or near bore ends  162 , as schematically illustrated in  FIG. 4 . 
         [0034]    In an example, ferrule  100  additionally includes two guide-pin bores  180  on respective sides of waveguide bores  160  and that lie in a common plane with ferrule central axis AF. Guide-pin bores  180  accommodate respective guide pins  190  that have respective front ends  192  and rear ends  194 . In an example, a guide-pin retention member  196  is arranged over ferrule rear section  103  and is fixed to guide pins  190  at or near guide-pin rear ends  194 . Guide-pin retention member  196  serves to secure guide pins  190  to ferrule  100 . In an example embodiment, guide pins  190  are metallic and serve as conducting members by being electrically connected at guide-pin rear ends  194  to electrical wire ends ME. 
         [0035]    In an alternate example embodiment, guide pins  190  are formed integral with ferrule  100 . 
         [0036]    Plug  20  also includes two plug electrical contacts  200  disposed on respective sides  26  of plug housing  21 . Plug electrical contacts  200  have respective rear portions that extend onto sidewalls  45  of rear section  44  of housing interior  40 . The two electrical wires  54  supported by fiber optic cable  50  and that have end portions  54 E that reside in housing rear section  44  are electrically contacted to electrical contacts  200  at respective rear portions  204  of the plug electrical contacts  200 . 
         [0037]      FIG. 5  is similar to  FIG. 4 , but shows ferrule  100  in a rear-biased position when subjected to an urging force illustrated by arrow  220 . Note that ferrule front end  102  has moved a distance D from its original forward-biased position to its rear-biased position. In example embodiments, distance D is in the range from 0.5 mm to 10 mm, more preferably in the range from 2 mm to 8 mm and even more preferably in the range from 5 mm to 7 mm. The forward-bias position is advantageous because it presents ferrule front end  102  substantially at recessed front end  22 R of housing  21 , and this allows for easy access to the ferrule front surface for cleaning the ferrule. This is important in applications where plug  20  is used to connect to commercial electronic devices, such as electronic device  300  introduced and discussed below, because contamination due to debris, liquids, etc., is anticipated to be a significant issue in establishing a proper electrical and optical connection. 
         [0038]      FIG. 6  is a top-down view of an example electronic device  300  and fiber optic cable assembly  10  next to the electronic device. Electronic device  300  has a housing  310  with a side  312 . Electronic device housing  310  supports the aforementioned receptacle  320  at housing side  312 . Receptacle  320  is a fiber optic interface device having a complementary geometry to plug  20  and is thus configured to matingly engage with plug  20 . 
         [0039]      FIG. 7A  is a close-up view of plug  20  shown adjacent receptacle  320  prior to connecting fiber optic cable assembly  10  to electronic device  300 . Note that ferrule  100  of plug  20  is in its forward-biased position in plug housing  21 , with ferrule front end  102  substantially at recessed front end  22 R of plug housing  21 . 
         [0040]    Receptacle  320  has a central axis A 2  and generally has a complementary geometry to plug  20 . In an example, receptacle  320  includes recess features  338  complementary to prongs  38  so that the prongs and recess features can engage and serve as an alignment guide when mating plug  20  to receptacle  320 . 
         [0041]    Receptacle  320  has first and second outer walls  340  that partially define recess features  338 . Receptacle  320  further includes first and second receptacle electrical contacts  350  respectively disposed on the first and second outer walls  340 . These first and second receptacle electrical contacts  350  come into contact with plug electrical contacts  200  of plug  20  when plug  20  is matingly engaged with receptacle  320 . 
         [0042]    Receptacle  320  also includes a receptacle ferrule  400  having a front end  402  and a rear end  404 . Receptacle ferrule  400  includes guide-pin holes  420  formed in receptacle ferrule front end  402  and sized to receive guide-pin front ends  192 . 
         [0043]    Receptacle ferule  400  also includes optical waveguide bores  460  that operably support receptacle optical waveguides  462 , such as receptacle optical fibers. Receptacle ferrule  400  is supported on a pedestal  470  defined by recess features  338 , with receptacle front end  402  residing near electronic device housing side  312 . Receptacle ferrule  400  is fixed in place, i.e., it is not configured to move. 
         [0044]    In an example, receptacle  320  includes circuit board  490  that operably supports an integrated optical engine  500  configured to transmit and receive optical signals ST and SR, and also to provide electrical power via receptacle electrical wires  554 . Receptacle  320  is optically connected to integrated optical engine  500  via receptacle optical waveguides  462 . Receptacle  320  is also electrically connected to circuit board  490  via receptacle electrical wires  554  that are electrically connected to the receptacle electrical contacts  350 . 
         [0045]      FIG. 7B  is similar to  FIG. 7A  but shows an example fiber optic interface assembly  570  constituted by plug  20  being matingly engaged with receptacle  320 . As plug  20  engages receptacle  320 , the front end  102  of plug ferrule  100  contacts the front end  402  of receptacle ferrule  400 . However, since receptacle ferrule  400  is fixed in place (i.e., is not movable), it urges plug ferrule  100  axially towards the rear end  24  of plug housing  21  as the plug  20  is inserted into receptacle  320 . Also, as plug  20  engages receptacle  320 , prongs  38  of plug housing  21  are received by the complementary receptacle recess features  338 , which serve to align plug  20  and receptacle  320 , e.g., maintain their respective axes A 1  and A 2  as substantially coaxial. In addition, guide pins front ends  192  of plug ferrule  100  enter guide-pin holes  420  of receptacle ferrule  400 . 
         [0046]    When plug  20  and receptacle  320  are fully engaged, prongs  38  are fully engaged within receptacle recess features  338 , guide pin front ends  192  are fully engaged with guide-pin holes, and the plug and ferrule front ends  102  and  402  are in contact, with waveguide bores  160  and  460  being substantially aligned with one another. In addition, plug ferrule  100  is in its rear-biased (i.e., retracted position) with resilient member  150  being in a compressed state. The distance D between the forward-biased position (as denoted by dashed line  22 R representing recessed end  22 R of plug housing  21 ) and the rear-biased position (as denoted by the dashed line  102 L corresponding to ferrule front end  102 ) is shown in  FIG. 7B . 
         [0047]    In an example, the friction established by the mating engagement of plug  20  and receptacle  320  is sufficient to overcome the spring force of resilient member  150  pushing against plug ferrule  100 , which force might otherwise act to push the plug out of the receptacle in the absence of a friction holding force. 
         [0048]      FIG. 8A  is a front-elevated view similar to  FIG. 2 , and  FIG. 8B  is a partial cut-away view that illustrates an example embodiment of fiber optic cable assembly  10  having a plug  20  that includes gradient-index (GRIN) lenses  600 . GRIN lenses  600  each have a front surface  602  and a rear surface  604 . GRIN lenses  600  are arranged in waveguide bores  160  with GRIN lens front surfaces  602  at respective bore front ends  162  or slightly recessed therefrom (e.g., by up to about 100 microns). Optical fibers  52  are arranged in respective waveguide bores  160  such that each optical fiber end  52 E is adjacent (e.g., is in contact with) the corresponding rear surface  604  of a GRIN lens  600 . 
         [0049]      FIG. 9  is similar to  FIG. 7B  and illustrates an example embodiment of fiber optic interface assembly  570  where plug  20  and receptacle  320  include respective GRIN lenses  600  and  600 ′.  FIG. 10  is a close-up view of the interface of plug  20  and receptacle  320  showing the interfaced GRIN lenses  600  and  600 ′. Each GRIN lens  600 ′ has a front surface  602 ′ and a rear surface  604 ′. GRIN lenses  600 ′ are supported by receptacle ferrule  400  in receptacle ferrule waveguide bores  460  so that GRIN lens front surfaces  602 ′ coincide with receptacle ferrule front end  402 , or are slightly set back therefrom (e.g., by up to about 100 microns). Receptacle optical waveguides  462  are arranged in receptacle ferrule waveguide bores  460  such that the receptacle optical waveguide ends  462 E are arranged adjacent (e.g., in contact with) GRIN lens rear surfaces  604 ′. 
         [0050]    In an example, two GRIN lenses  600  are included in plug  20  as transmit and receive GRIN lenses associated with transmit and receive plug optical fibers  52 , and two GRIN lenses  600 ′ are included in receptacle  320  as transmit and receive GRIN lenses associated with transmit and receive receptacle optical fibers  462 . 
         [0051]    Thus, transmit light  650 T generated by integrated optical engine  500  by an optical transmitter therein (not shown) travels as guided transmit light  650 TG in receptacle transmit optical waveguide  462  in the direction from receptacle  320  to plug  20 . This guided transmit light exits optical waveguide end  462 E and diverges as it enters GRIN lens  600 ′ at rear face  604 ′. GRIN lens  600 ′ acts to gradually bend the divergent transmit light  650 T until it becomes substantially collimated at front surface  602 ′. This substantially collimated transmit light  650 T enters front surface  602  of GRIN lens  600  of plug  20 . GRIN lens  600  acts to gradually bend substantially collimated transmit light  660 T until it becomes focused at near rear surface  604  and onto end  52 E of plug transmit optical fiber  52 . This focused transmit light  650 T is coupled into plug transmit optical fiber  52  and becomes guided transmit light  650 TG that travels through plug  20  and up through optical fiber cable  50 . 
         [0052]    Likewise, guided receive light  650 RG traveling in plug receive optical fiber  52  and generated upstream of fiber optic cable  50  travels through the optical fiber cable  52  and ultimately to optical fiber end  52 E, where it diverges into the corresponding GRIN lens  600  at rear surface  604  as divergent receive light  650 R. GRIN lens  600  acts to gradually bend the divergent receive light  650 R until it becomes substantially collimated at GRIN lens front surface  602 . This substantially collimated receive light  650 R exits GRIN lens front surface  602  and enters front surface  602 ′ of GRIN lens  600 ′ of receptacle  320 . GRIN lens  600 ′ acts to gradually bend substantially collimated receive light  650 R until it becomes focused at or near GRIN lens rear surface  604 ′ and thus focused onto the end  462 E of receptacle receive optical fiber  462 . This focused receive light  650 R is coupled into receptacle receive optical fiber  462  and becomes guided receive light  650 RG that travels through receptacle  320  and to an optical receiver (not shown) in integrated optical engine  500  (see  FIG. 9 ). 
         [0053]    It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.