%0 Journal Article
%T All-Optical Reversible Logic Gates with Optically Controlled Bacteriorhodopsin Protein-Coated Microresonators
%A Sukhdev Roy
%A Purnima Sethi
%A Juraj Topolancik
%A Frank Vollmer
%J Advances in Optical Technologies
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/727206
%X We present designs of all-optical reversible gates, namely, Feynman, Toffoli, Peres, and Feynman double gates, with optically controlled microresonators. To demonstrate the applicability, a bacteriorhodopsin protein-coated silica microcavity in contact between two tapered single-mode fibers has been used as an all-optical switch. Low-power control signals (<200£¿¦ÌW) at 532£¿nm and at 405£¿nm control the conformational states of the protein to switch a near infrared signal laser beam at 1310 or 1550£¿nm. This configuration has been used as a template to design four-port tunable resonant coupler logic gates. The proposed designs are general and can be implemented in both fiber-optic and integrated-optic formats and with any other coated photosensitive material. Advantages of directed logic, high Q-factor, tunability, compactness, low-power control signals, high fan-out, and flexibility of cascading switches in 2D/3D architectures to form circuits make the designs promising for practical applications. 1. Introduction There is tremendous research effort to achieve all-optical information processing for ultrafast and ultrahigh bandwidth communication and computing. The natural parallelism of optics along with advances in fabricating micro- and nanostructures has opened up exciting possibilities to generate, manipulate, and detect light and to tailor the optical molecular response for low-power all-optical computing [1¨C5]. A switch is the basic building block of information processing systems and optical logic gates are integral components of higher optical computing circuits. Conventional classical computing is based on Boolean logic that is irreversible, that is, the inputs cannot be inferred from the output, as the number of output bits is less than the inputs. This leads to destruction of information and hence to the dissipation of a large amount of energy [6¨C9]. Conservative and reversible logic circumvents this problem by having equal number of inputs and outputs and opening up the possibility of ultra-low power computing [6¨C9]. It is also compatible with revolutionary optical and quantum computing paradigms. Quantum arithmetic has to be built from reversible logical components, as unitary operations are reversible and hence quantum networks effecting elementary arithmetic operations such as addition, multiplication, and exponentiation cannot be directly deduced from their classical Boolean counterparts [10]. Several reversible logic gates have been proposed that include Fredkin gate (FG), Feynman gate, Toffoli gate (TG), Peres gate, and Feynman double gate
%U http://www.hindawi.com/journals/aot/2012/727206/