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Reis C.,Telecommunications Institute of Portugal | Parca G.,Telecommunications Institute of Portugal | Bougioukos M.,National Technical University of Athens | Maziotis A.,National Technical University of Athens | And 13 more authors.
Journal of Optical Communications and Networking | Year: 2014

In this paper, we address the experimental implementation of an all-optical packet routing scheme, with contention resolution capability, using interconnected semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (SOA-MZI) structures. Cross talk stemming from the blocked packets, due to the nonideal switching performed by the SOA-MZIs, is analyzed in every stage of the routing configuration. The routing functions and states performance are evaluated through bit-error ratio measurements and extinction ratio analysis. © 2014 Optical Society of America.


Reis C.,Telecommunications Institute of Portugal | Maziotis A.,National Technical University of Athens | Kouloumentas C.,National Technical University of Athens | Chattopadhyay T.,Kolaghat Thermal Power Station | And 8 more authors.
Optik | Year: 2013

In this paper, different approaches to implement all-optical flip-flops, working with a synchronization signal, will be presented and compared. In this type of optical bistable devices, the information present at the inputs produces effects on the outputs, throughout all the clock pulse period. The performance of optical clocked flip-flops will be studied in terms of extinction ratio (ER), switching energies and switching times. © 2012 Elsevier GmbH.


Reis C.,Telecommunications Institute of Portugal | Chattopadhyay T.,Kolaghat Thermal Power Station | Parca G.,Telecommunications Institute of Portugal | Dionisio R.,Telecommunications Institute of Portugal | And 4 more authors.
Optics and Laser Technology | Year: 2015

In this paper, all-optical logic functions, implemented with a single SOA-based Mach-Zehnder interferometer (SOA-MZI), are demonstrated experimentally and through numerical simulations. The proposed optical configuration is capable to carry out four logic operations, using simultaneously both output ports of the SOA-MZI. This may reduce the power cost and make possible to obtain simultaneously multi logic functions. The performance of such an architecture is assessed measuring the obtained extinction ratio (ER) for each Boolean function. The potential of integration makes the proposed scheme attractive to perform optical signal processing operations in next generation photonic transmission systems. © 2014 Elsevier Ltd. All rights reserved.


Chattopadhyay T.,Kolaghat Thermal Power Station | Reis C.,Telecommunications Institute of Portugal | Reis C.,University of Aveiro | Andre P.,Telecommunications Institute of Portugal | And 3 more authors.
Optics Communications | Year: 2012

A novel scheme for an all-optical clocked D flip-flop, with very low complexity, is proposed and numerically demonstrated. This new flip-flop configuration is based on a semiconductor optical amplifier - Mach-Zehnder interferometer (SOA-MZI), with a feedback loop, and presents two stable states determined by the phase shift between the two MZI arms. © 2011 Elsevier B.V. All rights reserved.


Chattopadhyay T.,Kolaghat Thermal Power Station | Reis C.,Telecommunications Institute of Portugal | Andre P.,Telecommunications Institute of Portugal | Andre P.,University of Aveiro | And 2 more authors.
International Conference on Transparent Optical Networks | Year: 2011

All-optical flip-flops are key elements in photonics switching techniques, which justify the continuous interest to develop new solutions for high-speed and low-power one-bit memories. In this paper, a novel scheme for all-optical clocked D flip-flop based on a single Mach-Zehnder interferometer, with semiconductor optical amplifiers in both arms (SOA-MZI), is numerically demonstrated. The proposed flip-flop will allow the synchronization of different optical devices and since its input presents the same value as the variables at the next state, are suitable for being used in finite state machines. Simulations results show that the proposed flip-flop can operate with switching energies below 20 fJ and presents high photonic integration capability © 2011 IEEE.


Chattopadhyay T.,Kolaghat Thermal Power Station
Applied Optics | Year: 2012

Computing with reversibility is the only way to avoid dissipation of energy associated with bit erase. So, a reversible microprocessor is required for future computing. In this paper, a design of a simple all-optical reversible programmable processor is proposed using a polarizing beam splitter, liquid crystal-phase spatial light modulators, a half-wave plate, and plane mirrors. This circuit can perform 16 logical operations according to three programming inputs. Also, inputs canbe easily recovered from the outputs. Itis named the "reversible programmable Boolean logic unit (RPBLU)." The logic unit is the basic building block of many complex computational operations. Hence the design is important in sense. Two orthogonally polarized lights are defined here as two logical states, respectively. © 2012 Optical Society of America.


Chattopadhyay T.,Kolaghat Thermal Power Station | Caulfield H.J.,Fisk University
Mechanical Systems and Signal Processing | Year: 2015

Nothing from nothing gives simple simile, but something from nothing is an interesting and challenging task. Adolf Lohmann once proposed 'do nothing machine' in optics, which only copies input to output. Passive logic module (PALM) is a special type of 'do nothing machine' which can converts inputs into one of 16 possible binary outputs. This logic module is not like the conventional irreversible one. It is a simple type of reversible Turing machine. In this manuscript we discussed and demonstrated PALM using mechanical movement of plane mirrors. Also we discussed the theoretical model of micro electro mechanical system (MEMS) based PALM in this manuscript. It may have several valuable properties such as passive operation (no need for nonlinear elements as other logic device require) and modular logic (one device implementing any Boolean logic function with simple internal changes). The result is obtained from the demonstration by only looking up the output. No calculation is required to get the result. Not only that, PALM is a simple type of the famous 'billiard ball machine', which also discussed in this manuscript. © 2014 Elsevier Ltd. All rights reserved.


Purkayastha T.,Maulana Abul Kalam Azad University of Technology | De D.,Maulana Abul Kalam Azad University of Technology | De D.,University of Western Australia | Das B.,Maulana Abul Kalam Azad University of Technology | Chattapadhyay T.,Kolaghat Thermal Power Station
Proceedings of the 3rd International Conference on Devices, Circuits and Systems, ICDCS 2016 | Year: 2016

Quantum dot Cellular Automata (QCA) is one of the major paradigm shifts in the field of nanoscale computing. Among various QCA alternatives, molecular QCA claims to have extremely high device density along with room temperature fabrication advantage. In a molecular QCA the quantum dots are formed within the redox centers of a molecule and columbic interaction between the molecules form the QCA network. In the proposed work a molecular four-dot QCA cell has been designed using a mixed-valence compound. A c/oso-hexaborate structure has been utilized to form the central molecule along with the four corner molecules responsible for forming the four dots. The corner molecules are observed to have a resonating characteristic. The counterion effect of the proposed mixed-valence compound is responsible for the formation of the QCA cell. The counterion effect is verified using combined DFT and NEGF studies revealing the charge localization at the two diagonal dots, which is the fundamental property of a QCA cell. © 2016 IEEE.

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