Optical computation is the most desirable technology that enhances the speed, data transmission rate and processing power by replacing the electronics with the optical switches. Optical switching is efficiently performed in high speed signal processing by all optical gates. This paper reviews the progressive development of the optical switching technology, highlights the different technologies of all optical gates and other switching circuits in all optical processing. Basic gates and other logic circuits in optical computing based on nonlinear regimes using semiconductor optical amplifier (SOA), fiber and photonic crystals are discussed, compared and the challenges along with future direction is outlined.

All optical switching and associated technologies: a review

Design of ring resonator based all optical switch for logic and arithmetic operations – A theoretical study

All-optical NOT and AND gates using counter propagating beams in nonlinear Mach–Zehnder interferometer made of photonic crystal waveguides

In recent years reversible logic has come as a promising solution in the optical computing domain. In reversible gates, there is one-to-one mapping between input and output, causing no loss of information. Reversible gates are useful for application in low power complementary metal-oxide semiconductors, with less dissipation, and in quantum computing. These benefits can be utilized by implementing reversible gate structures in the optical domain. In this paper, basic reversible Feynman and Fredkin logic gates using a lithium niobate based Mach-Zehnder interferometer are proposed. The different applications utilizing the proposed structures are also explained in this study.

Design of optical reversible logic gates using electro-optic effect of lithium niobate based Mach–Zehnder interferometers

Multiplexing and demultiplexing are the essential parts of any communication network In case of optical multiplexing and demultiplexing the coding of the data as well as the coding of control signals are most important issues Many encoding/decoding mechanisms have already been developed in optical communication technology Recently frequency encoding technique has drawn some special interest to the scientific communities The advantage of frequency encoding technique over any other techniques is that as the frequency is fundamental character of any signal so it remains unaltered in reflection, refraction, absorption, etc during transmission of the signal and therefore the system will execute the operation with reliability On the other hand, the switching speed of semiconductor optical amplifiers (SOA) is sufficiently high with property of best on/off contrast ratio In our present communication we propose a method of implementing a ‘4-to-1’ multiplexer (MUX) and a ‘1-to-4’ demultiplexer (DEMUX) exploiting the switching character of nonlinear SOA with the use of frequency encoded control signals To implement the ‘4-to-1’ MUX and ‘1-to-4’ DEMUX system, the frequency selection by multiquantum well (MQW)-grating filter-based SOA has been used for frequency routing purpose At the same time, the polarization rotation character of SOA has also been exploited to get the desired purpose Here the fast switching action of SOA with reliable frequency encoded control input signals, it is possible to achieve a faithful MUX/DEMUX service at tera-Hz operational speed

Method of implementing frequency encoded multiplexer and demultiplexer systems using nonlinear semiconductor optical amplifiers

A method of optical implementation of frequency encoded different logic operations using second harmonic and difference frequency generation techniques in non-linear material

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.

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

A novel method of developing all optical frequency encoded Fredkin gates

Reversible logic gates show potential roles in communication technology, and it has a wide area of applicability such as in sequential and combinational circuit of optical computing, optical signal processing, multi-valued logic operations, etc. because of its advantageous aspects of data-recovering capabilities, low power consumption, least power dissipation, faster speed of processing, less hardware complexity, etc. In a reversible logic gate not only the outputs can be determined from the inputs, but also the inputs can be uniquely recovered from the outputs. In this article an alternative approach has been made to develop three-input–output Fredkin and Toffoli gates using the frequency conversion property of semiconductor optical amplifier (SOA) and frequency-based beam routing by optical multiplexers and demultiplexers. Simulation results show the feasibility of our proposed scheme.

Sisir Kumar Garai

Papers

Method of implementing frequency encoded multiplexer and demultiplexer systems using nonlinear semiconductor optical amplifiers

A method of optical implementation of frequency encoded different logic operations using second harmonic and difference frequency generation techniques in non-linear material

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

A novel method of developing all optical frequency encoded Fredkin gates

Alternative approach of developing all-optical Fredkin and Toffoli gates