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Advances in Optical Technologies
Volume 2012 (2012), Article ID 727206, 12 pages
Research Article

All-Optical Reversible Logic Gates with Optically Controlled Bacteriorhodopsin Protein-Coated Microresonators

1Department of Physics and Computer Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282 110, India
2Biofunctional Photonics Group, The Rowland Institute, Harvard University, 100 Edwin H. Land Boulevard, Cambridge, MA 02142, USA
3Department of Electrical and Computer Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
4Wyss Institute for Biologically Inspired Engineering, Harvard University, HIM, 10th Floor, 4 Blackfan Circle, Boston, MA 02115, USA
5Laboratory of Biophotonics and Biosensing, Max Planck Institute for the Science of Light, 91058 Erlangen, Germany

Received 15 April 2011; Accepted 3 June 2011

Academic Editor: Ken-Tye Yong

Copyright © 2012 Sukhdev Roy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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 μW) 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.