A Novel All-Optical Frequency-Encoded Method to Develop Arithmetic and Logic Unit (ALU) Using Semiconductor Optical Amplifiers

An all-optical arithmetic and logic unit is the integral part of optical computing and data processing. In this paper, the author proposes a method to develop an all-optical arithmetic and logic unit by means of which so many binary logic operations such as AND, OR, NAND, NOR, EXOR, data comparator etc., as well as some arithmetic operations, such as half-addition, half-subtraction, full-addition, full-subtraction multiplication, etc., can be performed by properly selecting the frequencies of the control signals and using the frequency encoded input data. For this purpose, the author has exploited the frequency conversion scheme of semiconductor optical amplifier (SOA) using nonlinear polarization rotation character of the probe beam in SOA and, cross-gain modulation character of reflecting semiconductor optical amplifier (RSOA). Frequency-dependent optical beam routing to different channels have done using optical add/drop multiplexer made of SOA with multiquantum well structure. Frequency conversion efficiency of SOA and RSOA are very high as well as switching speed of SOA is very fast with very good ON-OFF contrast ratio.