Abstract:
Parallel data busses are embedded in multiple parallel grooves that are inscribed onto the exterior surface of a rectangular substrate or a cylindrical substrate that has a cylindrical hole running through the center thereof. These grooves which run along the length of the substrate may contain a suitable polymeric optical medium such as plexiglass or lexan or left entirely vacant to be filled with air. Optical transceivers placed to be orthogonal to the data busses and reflective conical structures positioned within the busses expedite the injection and retrieval of optical signals travelling through the data busses.

Description:
DEDICATORY CLAUSE 
     The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon. 
    
    
     BACKGROUND OF THE INVENTION 
     When designing a computer system that is intended for use on a missile, factors such as the size and the weight of the system as well as power consumption and the position the computer will occupy in the overall missile present unique challenges. A particularly vexing problem arises when the computer must be placed in front of a warhead that uses shaped-charge effects for its kill mechanism. In these missiles, a “free space” must be provided in front of the warhead to allow room for the formation of the “jet” that the warhead creates at detonation. 
     Other problems, some of which are not unique to computers in missilery, are the increased rate at which processors are required to communicate, either with themselves, memory or other devices, as new processors become faster and more processors are included in a single system. At increased communication rates, cross-talk between the individual data channels becomes more severe and more difficult to compensate for. Therefore, a data bus design is desired that accommodates the increased data transfer speed, requirement for ruggedness and economy of cost as well as a means to inject and retrieve signals easily while providing room for the formation of the jet created by the warhead of a missile. 
     SUMMARY OF THE INVENTION 
     Parallel data busses are embedded in multiple parallel grooves that are inscribed onto the exterior surface of a rectangular substrate or a cylindrical substrate that has a cylindrical hole running through the center thereof. In the case of the cylindrical substrate, the center hole provides a means for allowing the jet formation from shaped charged warheads to occur unencumbered while embedding the data busses into the body of the cylinder provides a degree of ruggedness. These grooves may contain a suitable polymeric optical medium such as plexiglass or lexan or left entirely vacant to be filled with air. Optical transceivers placed to be orthogonal to the data busses and reflective conical structures positioned within the busses expedite the injection and retrieval of optical signals travelling through the data busses. 
    
    
     DESCRIPTION OF THE DRAWING 
     FIG. 1 depicts a representative circuit card having a center hole through which the cylindrical substrate is inserted. 
     FIG. 2 shows several circuit cards stacked longitudinally through the center holes of which the cylindrical substrate is inserted. 
     FIG. 3 illustrates the cylindrical substrate on the outer surface of which the data busses are embedded. 
     FIG. 4 shows an optical rod having a cone milled into one end. 
     FIG. 5 illustrates the placement of an optical rod in the data bus. 
     FIG. 6 is a representative diagram of the relative positions of a primary groove and a secondary groove on the outer surface of the cylindrical substrate. 
     FIG. 7 shows details of the integration positions of the optical transceiver, the conical structure and the alignment blocks. 
     FIG. 8 indicates a possible position of alignment pins. 
     FIG. 9 shows a rectangular substrate with data busses embedded on the surface thereof. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing wherein like numbers represent like parts in each of the several figures, FIG. 1 shows representative circuit card  101  containing the computer components (not detailed in the figure) which must communicate. Circuit card  101  has in its center hole  103  which is large enough to accommodate therethrough cylindrical substrate  301 . Several such cards may be stacked together longitudinally as shown in FIG. 2, each separated from the other by a variable pre-determined distance. The cylindrical substrate, which may be made of reflective material (metal or plated polymer), also has through its center cylindrical hole  305  that serves to provide room for the jet formation from shaped charged warheads to occur unencumbered upon detonation of the missile, the cylindrical substrate being placed in front of the warhead in the missile. Further, the substrate has inscribed onto its outer surface many identical grooves  303  that are parallel to each other and run along the length of the substrate. The shape of the grooves as well as the number of them depends on the communication needs which the data busses embedded in the grooves are to fulfill. However, it is envisioned that the width and depth of each groove have the same numerical value. Grooves  303  may be filled with optically transparent polymer material such as plexiglass or lexan or left vacant to be filled with air. If using a polymer material, the material may be applied as a liquid into the grooves and allowed to solidify, thereby contributing to the reduction of the manufacturing costs. 
     Optical transceivers  105 , mounted onto the perimeter of center hole  103  of circuit card  101 , provide a means for injecting optical signals into and retrieving them from the optical medium. The optical transceivers must be mounted such that when cylindrical substrate  301  is inserted through center hole  103 , each transceiver  105  is positioned orthogonally with respect to the optically-conducting medium of a groove. An example of a possible transceiver is the active elements of the Motorola MT-RJ connector (HFBR-5903/5905), though a device with transmitter and receiver manufactured coaxially on a single substrate would be preferred. 
     In operation, when information needs to be transmitted from one circuit card to another, the first card impresses an electrical signal on various of its optical transceivers which convert these electrical signals to optical signals and inject these optical signals into the optical media of grooves  303 . The signals travel by means of internal reflection within the grooves until received by optical transceivers of the second card. The received optical signals are converted back to electrical signals for use by the devices on the second card. 
     To allow for additional data bandwidth, one may provide for multiplexing of each groove by providing multiple optical transceivers for each groove on each circuit card, with each of the transceivers emitting and detecting optical signals of different wavelength from those of the other transceivers on that same card. 
     FIGS. 4 and 5 show a low-cost means for inserting an optical signal into an optical data bus when the signal source is orthogonal to the optical medium as in the case of the transceiver position with respect to the groove when circuit cards  101  of FIG.  1  and cylindrical substrate  301  of FIG. 3 are fitted together correctly in accordance with above description. Most extant optical transmission systems are point-to-point, that is, an optical signal is injected into one end of an optical channel and detected at the other end. In such systems, alignment of the source and detector with the optical channel can be critical. If it is desired that a signal be injected into the channel or detected at some point other than the end of the channel, an optical gradient needs to be used. Careful alignment of the components is necessary because the emitter/detector is at a non-orthogonal angle to the optical channel and each gradient inserted into the optical medium may introduce a transmission loss of up to 50%. 
     A solution to avoid such losses is depicted in FIG. 4 which shows optically conductive rod  401  made of a suitable polymer material that has milled into one end thereof cone  403 . An optical transceiver  405  is attached to the other end of the rod, above the apex of the cone. This rod-transceiver combination unit is inserted directly into the optical medium of groove  303  at a right angle to the groove as shown in FIG.  5 . When the transceiver generates an optical signal, the signal travels down the rod and reflects from the cone in all directions, with a portion of the reflected signal travelling down the optical medium. When the travelling signal strikes another like-positioned cone along the way, then the signal is reflected by the second cone up its corresponding rod into the second transceiver. It is envisioned by the inventors that the slope of the cones be 45 degrees, that their height be one half of the value of the depth of groove  303  and that the surface of the cone be treated suitably to enhance its reflectivity. It is further envisioned that the height of rod  401  equals the depth of groove  303  and the tranceiver is mounted to protrude above the groove. Any number of the rod-transceiver combination units can be embedded into one or more grooves to achieve a desired result. 
     FIGS. 6 and 7 show another low-cost means for injecting and retrieving optical signals. A representative primary groove  303  and a representative secondary groove  601  cross each other at right angle. At the intersection  603 , reflective cone  403  is placed with its apex pointing up. This cone is maintained in place by two optional alignment blocks  701 which fit into the secondary groove on opposing sides of the cone. Transceiver  405 , mounted above the cone, emits an optical signal which travels down the polymer rod (not depicted in FIGS. 6 and 7) between the cone and the transceiver and, from the cone, is reflected in all directions. Thereafter, a portion of the reflected signal is captured by a second cone down the groove and reflected again in all directions. A transceiver above the second cone processes the signal for appropriate use. Alternatively, cone  403  may be fabricated directly into the base of the groove. In such a case, the optical transceiver should be aligned with the cone via alignment pins  801  which are mounted directly into the substrate. This alternative design obviates the need for secondary grooves. Also, it is noted that even though FIGS. 5,  6  and  8  show the substrate underlying a groove as a rectangular form, it is for illustration purposes only and the entire substrate is of cylindrical shape. However, it is possible that the substrate may be “unrolled” and presented in a rectangular form if cylindrical hole  305  is not necessary for any given application. 
     Although a particular embodiment and form of this invention has been illustrated, it is apparent that various modifications and embodiments of the invention may be made by those skilled in the art without departing from the scope and spirit of the foregoing disclosure. Accordingly, the scope of the invention should be limited only by the claims appended hereto.