A New Carry-Free Adder Model for Ternary Optical Computer

Based on parallelism of MSD addition, a new carry-free adder model for optical computer is proposed. Using MSD number system and four kinds of logic transforms, the model is built with input part and three optical calculators. With the model, addition is implemented with only logic operations without any carry. This can greatly improve the efficiency of addition operation. To guarantee the feasibility of the implementation of the model, the alignment issue between the data bits of operands on different optical calculators is discussed. And the method to solve the problem that the input state of light is dark while the output state is bright in the process of logic transform is put forward. The analysis results show that the model is correct and can much improve the efficiency of the adder compared with the traditional adder model.