Fast hybrid parallel carry look-ahead adder.

A new optical parallel arithmetic processing scheme using a nonholographic optoelectronic content-addressable memory (CAM) is discussed. The design of a four-bit CAM-based optical carry look-ahead adder (CLA) is presented. Compared with existing optoelectronic binary addition approaches, this nonholographic CAM scheme offers a number of practical advantages, such as faster processing speed and ease of optical implementation and alignment. For the addition of numbers longer than four bits, by incorporating the previous stages' carry, a number of four-bit CLA's can be cascaded. Experimental results are also presented.