reference will now be made to the drawings to describe various aspects of exemplary embodiments of the invention . it is to be understood that the drawings are diagrammatic and schematic representations of such exemplary embodiments , and are not limiting of the present invention , nor are they necessarily drawn to scale . in the following description , numerous specific details are set forth in order to provide a thorough understanding of the present invention . it will be obvious , however , to one skilled in the art that the present invention may be practiced without these specific details . in other instances , well - known aspects of optical systems have not been described in great detail in order to avoid unnecessarily obscuring the present invention . referring now to fig1 a and 1b , fig1 a schematically illustrates an embodiment of a network traffic access port (“ tap ”) 106 according to the invention in an example network environment . as illustrated , tap 106 is connected to a pluggable optoelectronic module such as an optical transceiver module 102 . the optical transceiver module is in turn connected to a port in a network device 104 , such as a switch , a host bus adapter , a redundant array of independent disks ( raid ), or other network device to which an optical transceiver may be connected . the optical transceiver module 102 can be any of various types of transceiver modules that pass data bidirectionally , meaning that the module has a transmitter optical subassembly with a laser that transmits data out into the network and a receiver optical subassembly that receives data in from the network . such a transceiver passes incoming data through a first cable connector ( not illustrated ) and outgoing data through a second cable connector ( not illustrated ). for example , a preferred transceiver module for use with the network taps of the invention is a conventional sfp transceiver module . an sfp module is bidirectional , having incoming and outgoing connector ports at a duplex connector . further details regarding conventional sfp device configurations are well known in the art and can be found , for example , in the “ small for factor pluggable ( sfp ) transceiver multisource agreement ( msa )”, ( sep . 14 , 2000 ), which is incorporated herein by reference . other standard and future transceivers and their respective interface connectors are also well known in the art , or will be well known in the art , and are also included within the scope of the invention . in normal operation , transceiver module 102 would transmit and receive optical signals on optical cables 164 and 166 . when tap 106 is inserted , however , optical signals are routed through tap 106 between transceiver module 102 and optical cables 164 , 166 . the tap 106 also diverts a copy of incoming and / or outgoing the optical signals onto cables 168 and 170 to a connected network device 108 . network device 108 can be , for example , a network analyzer , a mass storage device for storing captured data , or any other device where it is desired to receive the copied or split optical signal . referring now to fig1 b , the taps of the present invention are three port devices , including a “ transceiver ” port 150 that connects directly with an optical transceiver , a “ link ” port 152 that connects with the network link ( cables 164 , 166 ) that communicates with the transceiver , and a “ tap ” port 154 that connects with network device 108 that accesses the tapped network data . as used herein , the term “ port ” denotes a communications access point , including both male and female adapters , other connectors , and wireless components . as previously noted , one skilled in the art will recognize that the illustrations do not depict required port forms or configurations . by way of example only , in a preferred embodiment of the invention , transceiver port 150 will be an sfp duplex cable connector such that it can plug into a duplex transceiver connector on an sfp transceiver module . similarly , link port 152 will be an sfp duplex transceiver connector such that a duplex cable connector on cables 164 and 166 can quickly and easily be attached . tap port 154 is more flexible and can be selected to match the desired hardware for cable 168 and 170 and network device 108 . the preferred embodiment of the invention wherein ports 150 and 152 replicate the cable and transceiver ports between which it will be inserted serves to make the device easy to insert and remove into a network . alternatively , additional adapters can be used to insert tap 106 if necessary for compatibility with the connectors on transceiver 102 and cables 164 , 166 . as shown in fig1 b , the tap 106 includes a pair of couplers 156 , each associated with one of the directional links of the sfp module . the couplers split a portion of the data signals out of the associated links such that a network analysis device connected to the tap can access the network data . as noted in fig1 a and 1b , a network device 108 connected to the tap 106 can obtain incoming data from the link port 150 and the transceiver port 152 , thereby accessing data from both of the directional links of the transceiver . more particularly , optical link 112 passes through a coupler 156 where a portion of an optical signal is split and sent on optical link 116 to tap port 154 and on to network device 108 . similarly , optical link 110 passes through a coupler 156 where a portion of an optical signal is split and routed on optical link 114 to tap port 154 and on to network device 108 . the couplers 156 within the tap 106 can have any desired split ratios . for example , the couplers 156 can provide a split ratio of 70 / 30 , meaning that 70 % of the optical power passes through a coupler 156 and remains in the network link and 30 % is diverted from the tap 106 to the network device 108 . the split ratio that is used in any particular situation is determined by the light loss budget constraints of the network and the amount of power required by the network analysis device . the taps shown in fig1 are 1 × 1 taps , meaning that there is one tap port for each tapped bidirectional link . the taps of the invention can also have other numbers of tap ports ( e . g ., 1 × 2 or higher - order taps ). however , 1 × 1 taps are generally preferred because of the space constraints and light loss budget constraints that often exist . referring now to fig2 , the tap port 154 and the link port 152 can be aligned in various configurations depending on the space constraints associated with the ports on the network device . for example , the port for the network link and the port for the network analysis device can have a horizontal configuration 204 or a vertical configuration 202 as illustrated in the alternative configurations in fig2 . interfaces 155 , 157 , 159 , and 161 are depicted to illustrate one preferred arrangement of such interfaces for connecting with optical cables at the tap and link ports . the taps of the invention can be discrete components that can be removably connected to a pluggable optical transceiver module as illustrated above . in other embodiments , the taps can be integrated into an optical transceiver module rather than being a separate component , in which case transceiver port 150 may be omitted in certain embodiments . although the invention is described herein primarily in reference to small form factor pluggable ( sfp ) modules , the principles of the invention can also be applied to taps that can be used with other communication modules , such as small form factor ( sff ) modules , other optoelectronic transceiver modules or other types of transceivers . because the taps of the invention are relatively small and have only a single port to be accessed by a network analysis device , the taps can be relatively inexpensive . thus , the taps of the invention can reasonably permit a network administrator to install taps in as many as all of the network links of a network . as network problems are experienced , the network administrator can connect a network analysis device to any of the links that might be useful to analyze . the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics . the described embodiments are to be considered in all respects only as illustrative and not restrictive . the scope of the invention is , therefore , indicated by the appended claims rather than by the foregoing description . all changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope .