Abstract:
A modular connector having multiple ports, comprising a housing having a first end and a second end, a first optical port on the first end, a second optical port on the first end, a third optical port on the second end, a fiber bragg grating (FBG) within the housing optically connected to the first port, said FBG configured to reflect a set wavelength back and away from the first port, a coupler within the housing optically connected to the FBG, the second port, and the third port; and wherein each of said optical ports, once connected, is capable of supporting the housing without additional support.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to optical connectors. More particularly, the present invention relates to a modular connector for an optical network including wavelength division multiplexing (WDM) capability.  
         BACKGROUND OF THE INVENTION  
         [0002]    Due to the increasing electronic traffic on optical networks, maximizing bandwidth per each optical fiber utilized in transmitting optical signals is becoming a necessity. Optical fibers are capable of transmitting multiple wavelengths at various frequencies in order to maximize the amount of information that can be carried on a single optical fiber in a communication network. Of course, eventually particular wavelengths being carried on an optical fiber will need to be separated. The process of combining, transmitting, and separating signals of different wavelengths is referred to as wavelength division multiplexing (WDM).  
           [0003]    Conventional WDM systems utilize numerous, bulky, discrete components that are connected using a myriad of optical fibers. If the number of wavelengths to be separated or added to an optical system is large, the amount of required discrete components dictates the use of a large enclosure to contain all the elements. WDM systems therefore require planning and close matching of laser characteristics with wavelength combiners (multiplexers) and separators (demultiplexers).  
           [0004]    Accordingly, there is a need for a modular, inexpensive, and easy-to-use wavelength multiplexer (mux) and demultiplexer (demux) that is capable of being used selectively to reduce parallel fiber connections down to a single fiber link.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0005]    An object of the present invention is to provide a modular wavelength division multiplexing (WDM) connector capable of being retrofitted to existing parallel fiber connections.  
           [0006]    A second objective of the present invention is to eliminate racks currently required for conventional WDMs in favor of a self-supportive connector or adapter.  
           [0007]    A third object of the present invention is to reduce to the cost of WDM systems by integrating numerous discrete components into a single module.  
           [0008]    A fourth object of the present invention is to reduce failures and defects associated with systems utilizing multiple discrete components.  
           [0009]    A fifth object of the present invention is to provide the flexibility of a modular design to WDM systems based on individual laser transmitters.  
           [0010]    In that regard, the present invention provides a modular connector having multiple ports, comprising a housing having a first end and a second end, a first optical port on the first end, a second optical port on the first end, a third optical port on the second end, a fiber Bragg grating (FBG) within the housing optically connected to the first port, said FBG configured to reflect a set wavelength back and away from the first port, a fiber coupler within the housing optically connected to the FBG, the second port, and the third port; and wherein each of said optical ports, once connected, is capable of supporting the housing without additional support.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a functional diagram of a modular WDM connector configured in accordance with the present invention functioning as a wavelength coupler;  
         [0012]    [0012]FIG. 1 a  is a plan view of the modular WDM connector diagrammed in FIG. 1;  
         [0013]    [0013]FIG. 1 b  is a plan view of a modular WDM connector providing a pig-tailed or cable-ended configuration in accordance with a second embodiment of the present invention;  
         [0014]    [0014]FIG. 1 c  is a plan view of a modular WDM connector providing a pig-tailed or cable-ended configuration in accordance with a third embodiment of the present invention;  
         [0015]    [0015]FIG. 1 d  illustrates an LC connector and adaptor that may be utilized on the ports of the present invention;  
         [0016]    [0016]FIG. 2 is a functional diagram of a modular WDM connector shown in FIG. 1 functioning as a wavelength divider;  
         [0017]    [0017]FIG. 3 is a functional diagram of a pair of modular WDM connectors for coupling two different wavelengths at a transmitting end, transmitting the wavelengths over a single optical fiber, and separating the wavelengths with a pair of modular WDM connector at a receiving end in accordance with the present invention;  
         [0018]    [0018]FIG. 4 is a functional diagram of a pair of modular WDM connectors configured in accordance with the present invention enabling full-duplex transmission of multiple wavelengths over a single optical fiber;  
         [0019]    [0019]FIG. 5 is a functional diagram of a modular WDM connector configured in accordance with a fourth embodiment of the present invention;  
         [0020]    [0020]FIG. 6 is a functional diagram of a modular WDM connector configured in accordance with a fifth embodiment of the present invention; and  
         [0021]    [0021]FIG. 7 is a functional diagram of a modular WDM connector configured in accordance with a sixth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    Referring now to the drawings, FIG. 1 shows a modular WDM connector  10  configured in accordance with the present invention. A housing  12  having connectors or ports  14 ,  16  and  18  is illustrated. The ports  14 , 16  are preferably SC singlemode optical connectors, such as those manufactured and sold by Stratos Lightwave, in Chicago, Ill. Port  18  is preferably an SC optical adapter, such as those manufactured by Corning Cable Systems, in Corning, N.Y. Of course, other optical connectors can be utilized for ports  14 , 16 , 18  in the present invention. For example, ports  14 , 16  can be LC optical connectors which are manufactured and sold by Stratos Lightwave in Chicago, Ill.  
         [0023]    Port  14  is connected to optical fiber  20 , and port  16  is connected to optical fiber  22 . Port  18  is connected to optical fiber  24 . A fiber Bragg grating  26  is attached to the optical fiber  20 , such as manufactured by Gould Fiber Optics of Millersville, Md. Fiber Bragg gratings are also manufactured by Excelight, in Durham, N.C. A fiber optic bi-directional coupler  28  is optically connected to all the optical fibers  20 , 22 , 24 . A fiber optic coupler, such as manufactured by Gould Fiber Optics, may be utilized in the present invention for the bi-directional coupler  28 .  
         [0024]    A post or support member  30  is provided to prevent the fiber optic  22  from breaking or being damaged due to overbending at an arc or bend  32  in optical fiber  22 . Furthermore, a channel, groove, or second support member  21  also functions to properly position the optical fiber  21  within the housing  12 .  
         [0025]    The housing  12  is preferably constructed of plastic or other polymer that may be molded to a desired shape. The fiber Bragg grating  26  and the fiber optic bidirectional coupler  28  are preferably secured within the housing  12  by using an adhesive or support brackets formed into the housing  12 . Similarly, the ports  14 , 16 , 18  are attached to the housing  12  by using an adhesive or via support brackets formed into the housing  12 .  
         [0026]    As shown in FIG. 1, a first wavelength (λ 1 ) and a second wavelength (λ 2 ) enter the connector  10  via optical ports  14  and  16 , respectively. λ 1  is carried along optical fiber  20  into and through the fiber Bragg grating (FBG)  26  to the coupler  28 . λ 2  is carried along optical fiber  22  and into and through the bidirectional coupler  28 . The FBG  26  is configured to reflect λ 2  while allowing other wavelengths to pass though the FBG  26 . Accordingly, λ 2  is reflected back from the FBG  26  and towards coupler  28  along optical fiber  24 . λ 2  passes though the coupler  28  and exits the coupler  28  via optical fiber  24  towards optical port  18 . λ 1  simply continues along fiber  20 , through the FBG  26 , into the bidirectional coupler  28 . λ 1  then exits the coupler  28  on fiber  24  towards the optical port  18 . In this manner λ 1  and λ 2  are combined to be carried along fiber  24  and exit the connector  10  via port  18 . λ 1  also travels down fiber  22  and exits connector  16 .  
         [0027]    Using the FBG  26  in combination with the bidirectional coupler  28  is preferred over an optical splitter/coupler which simply adds wavelengths from separate fibers to a single fiber. An FBG in combination with a bidirectional coupler enables wavelengths having very close frequencies to be accurately combined to and/or divided from a single optical fiber. Conventional optical splitters/couplers are unable to accurately add or subtract wavelengths having very close frequencies from a single optical fiber.  
         [0028]    [0028]FIG. 1 a  illustrates a connector  10   a  having a housing  12   a  that is configured to accommodate an SC configuration. Ports  14   a  and  16   a  include male SC connectors. Port  18   a  includes an SC adapter.  
         [0029]    [0029]FIG. 1 b  illustrates a connector  10   b  having a housing  12   b  configured in accordance with a second embodiment of the present invention. The ports  14   b  and  16   b  include male SC connectors. Port  18   b  also includes a male SC connector. In accordance with the second embodiment of the present invention, the port  18   b  is attached to the housing  12   b  using a pig-tailed or cabled ended configuration via an optical cable  19   b.    
         [0030]    [0030]FIG. 1 c  illustrates a connector  10   c  having a housing  12   c  configured in accordance with a third embodiment of the present invention. The ports  14   c  and  16   c  include male SC connectors. Port  18   c  includes an SC adapter. In accordance with the third embodiment of the present invention, the ports  14   c  and  16   c  are attached to the housing  12   c  using a pig-tailed or cabled ended configuration via optical cables  31   c  and  32   c,  respectively.  
         [0031]    [0031]FIG. 1 d  illustrates an LC simplex connector  51 , an LC duplex connector  53 , an LC simplex adapter  55 , and an LC duplex adapter  57 . The ports of the present invention can be modified to accommodate an LC configuration using such connectors and adapters.  
         [0032]    [0032]FIG. 2 illustrates the WDM connector  10  functioning to separate multiple wavelengths from a single fiber, instead of adding multiple wavelengths to a single fiber as shown in FIG. 1. The connector  10  shown in FIG. 2 is identical in structure as the WDM connector  10  shown in FIG. 1. The only difference is the WDM connector shown in FIG. 2 functions to separate multiple wavelengths entering on a fiber connected to port  18 . As such, λ 1  and λ 2  enter the connector  10  via port  18  and are both carried along single optical fiber  24 . λ 1  and λ 2  both enter the bi-directional coupler  28 , pass though the bi-directional coupler  28 , and exit the bi-directional coupler via fiber  20 . λ 1  and λ 2  both enter the FBG  26 , but only λ 1  passes though the FBG  26  and out port  14 . λ 2  is reflected back towards and into the bi-directional coupler  28  by the FBG  26 , and λ 2  exits the out the coupler  28  via fiber  32  and out port  16 . In this manner, the WDM connector  10  functions to separate multiple wavelengths from a single fiber.  
         [0033]    [0033]FIG. 3 illustrates how two WDM connectors configured in accordance with the present invention can be integrated into a communication system to combine multiple wavelengths onto a single optical fiber  34 , transmit multiple wavelengths a distance over the single fiber  34 , and then separate the multiple wavelengths at the receiving end using the WDM connector. In FIG. 3 two WDM connectors  11  and  13  are shown. Connectors  11  and  13  are structurally identical to the WDM connectors  10  shown in FIGS. 1 and 2, but are identified in FIG. 3 as the connectors  11  and  13  to distinguish between the transmitting connector  11  and the receiving connector  13 . Connector  11  operates as discussed in reference to connector  10  in FIG. 1, and connector  13  operates as discussed in reference to connector  10  in FIG. 2.  
         [0034]    [0034]FIG. 4 illustrates how two WDM connectors  11  and  13  configured in accordance with the present invention can be combined to enable full-duplex communication over a single optical fiber  34  using two different wavelengths, λ 1  and λ 2 . Once again, connectors  11  and  13  are identical, and operate as discussed in reference to FIG. 3. The only difference in FIG. 4 is that connectors  11  and  13  are both simultaneously operating as transmitters and receivers, and as dividers and couplers.  
         [0035]    [0035]FIG. 5 illustrates a WDM connector  50  constructed in accordance with a fourth embodiment of the present invention. The WDM connector  50  operates in the same manner as the WDM  10  connector discussed in FIGS.  1 - 4 , except the number of ports  52 , 54 , 56 , 58  is increased from two to four. In this manner four different wavelengths can be combined into a single fiber  84  that exits out the port  55 . In this case FBGs  60 , 62 , 64  are tuned to pass wavelengths λ 2 , λ 3 , λ 4 , respectively. It should be clear that more or less ports may be added to accommodate the number of unique wavelengths being utilized. Similarly, it should be clear that the WDM connector  50  can function as either a coupler to combine multiple wavelengths to a single optical fiber, or as a divider to separate multiple wavelengths from a single optical fiber.  
         [0036]    [0036]FIG. 6 illustrates a connector  90  configured in accordance with a fifth embodiment of the present invention. The connector  90  is designed to provide a compact optical module for multiple wavelengths that are not very close together in frequencies, or do not require the efficiency and accuracy of a WDM module using an FBG. The connector  90  has two input ports  92  and an output port  96 . λ 1  and λ 2  enter the module through respective ports  92 , 94  and are combined via a conventional optical coupler  100 , such as produced by Gould Fiber Optics. The combined wavelengths λ 1  and λ 2  exit the module  90  on a single fiber  101  via port  96 . Of course, more input ports can be added to the modular connector  90 .  
         [0037]    [0037]FIG. 7 illustrates a connector  102  constructed in accordance with a sixth embodiment of the present invention. Similar to the connector  90  shown in FIG. 6, the connector  102  is designed to provide a compact optical divider module for multiple wavelengths that are not very close in frequencies, or do not require the efficiency and accuracy of a WDM using an FBG. For example, WDMs combined with FBGs can discriminate between wavelengths as close as 0.8 nanometers. Conventional couplers or splitters are designed to manipulate wavelengths having larger discrepancies, such as 1310 nm, 1480 nm, and 1550 nm.  
         [0038]    Operationally, wavelengths λ 1  and λ 2  enter the divider connector  102  via port  108  along single optical fiber  116 . λ 1  and λ 2  enter and exit splitter  114  via both fibers  118  and  120 . The splitter  114  is of conventional design such as produced by Gould Fiber Optics. λ 1  and λ 2  both enter wavelength filters  110  and  112  via optical fiber  118  and  120 , respectively. Filter  110  prevents λ 1  from passing and thus allows only λ 2  to continue on to the port  104 . Similarly, filter  112  prevents λ 2  from passing and thus allows only λ 1  to continue on to port  106 . In this manner a compact divider module is provided for separating multiple wavelengths from a single fiber.  
         [0039]    It is to be understood that the foregoing description is merely a disclosure of particular embodiments and is no way intended to limit the scope of the invention. Several possible alterations and modifications will be apparent to those skilled in the art.