1. An optical computing apparatus for adding two numbers represented by a sequence of binary bits by generating a partial sum term, a partial carry term, a look-ahead carry term and a true sum term, comprising: means for converting the sequence of binary bits corresponding to the two numbers to be added into terms representing the partial sum and the partial carry of the two numbers, the partial sum and carry terms being represented by binary data bits; means for negating the partial sum and partial carry terms; input means comprising a plurality of elements, each of which is responsive to a corresponding one of the binary data bits representing the negation of the partial sum term and partial carry terms of the two numbers to be added and which projects an optical signal representative of the logical state of the corresponding binary bit along a different one of a first set of signal paths; control means comprising a plurality of elements, each of which is associated with a different one of the paths in the first set of signal paths, the control means elements receiving the optical signal projected along the associated signal path and broadcasting the received optical signal along a set of selected signal paths, wherein the signal paths in the sets of selected signal paths collectively form sets of coincident signal paths, wherein each set of coincident signal paths is coincident at an associated detect location, and further wherein the signal paths contained in a particular set of coincident signal paths are selected so that the optical signals which the set routes to the associated detect location represent the bits in a desired combination of the binary bits representing the negation of the partial sum and partial carry terms; binary detector means comprising a plurality of elements, each of which is associated with a different one of the associated detect locations and is responsive to the optical signals routed to the associated detect location, wherein each element of the binary detector means includes: means for detecting the optical signals routed to the associated detect location by detecting only the presence or absence of an optical signal; means for performing a logical negation of the detected presence or absence of an optical signal; and means for producing an output representative of the result of the logical negation means, wherein the output of the elements of the detector means is a sequence of binary bits representing the look-ahead carry term and is formed from the binary bits representing the negation of the partial sum and partial carry terms; and means for performing an exclusive OR operation on the binary bits representing the partial sum term and the look-ahead carry term to obtain a sequence of binary bits representing the true sum of the two numbers.