%0 Journal Article
%T All-Optical Logic Gates: Designs, Classification, and Comparison
%A Pallavi Singh
%A Devendra Kr. Tripathi
%A Shikha Jaiswal
%A H. K. Dixit
%J Advances in Optical Technologies
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/275083
%X The paper reviews the current status and designs of all-optical gates. Various schemes with and without semiconductor optical amplifiers are discussed and compared. The optical gates are classified according to their design structures. It is divided into two major divisions that is, nonsemiconductor optical amplifier based gates and semiconductor optical amplifier based gates. In nonsemiconductor optical amplifier based gates, different schemes have been proposed to create non-linearity which is discussed. The semiconductor optical amplifier based gates of different design structures are discussed to show the probe pulse that is modulated in different ways to obtain results. 1. Introduction Today the demand for high bandwidth has rapidly increased to obtain the speed limit of electronic devices. The general purpose of all-optical signal processing is still on the horizon. Nowadays, prototype of all-optical logic gates at high bit-rate are coming out from the laboratories. The researches are going forward in this field to make it possible. However, in optical signal processing the digital gates have complicated and cumbersome electrooptic conversion. To make all-optical systems, it is necessary that entire components which are used in optical networks such as add-drop multiplexer, packet synchronization, clock recovery, address recognition, and signal regeneration, and so forth should be all-optical elements. To make the dream come true the basic requirement is optical gates. Gates are the key elements to realize all-optical functions. Thus, to realize digital gates into all-optical logic gates at the same platform, it is necessary to develop several basic designs. It is impractical to design an optical component with some gates using ultrafast nonlinear interferometer (UNI), some gates with SOA and some with high nonlinear fiber (HNLF). So the design is only successful when all the gates are implemented with same technique. All-optical logic gates are core logic unit to implement various all-optical systems for optical signal processing. To design optical gates it is necessary to implement a nonlinear medium which modulates the signal to produce the desired results. The nonlinearity may be generated in numerous ways such as using nonlinear loop mirror, nonlinear fiber, photonic crystal, filter, waveguide, thyristor, acoustic waves, or semiconductor optical amplifier. Therefore, there are many researches going on to realize all-optical signal processing systems which are already discussed in various papers. It may be classified in multiple ways according
%U http://www.hindawi.com/journals/aot/2014/275083/