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Āsansol, India

Optical adder/subtractor for two four-bit frequency encoded binary numbers are proposed and designed based on four wave mixing, add drop multiplexing and frequency conversion in semiconductor optical amplifier. The input bits and the control input are intensity-modulated signal of two specific frequencies suitable for optical communication in the C band of wavelength. The device can distinguish negative and positive results and controlled operation are most promising in this proposal. The use of semiconductor optical amplifiers along with frequency encoding makes the system very fast and useful for future optical communication and computation systems. © 2014 Elsevier GmbH. All rights reserved.

All optical signal processing has capability of handling huge amount of data. This has become possible by the use of multi-valued logic in place of binary logic. In this communication a frequency encoded tri-state logic gates NOT, AND and NAND are proposed for the first time using difference frequency generation in non-linear materials. The operating principle of the logic gate is the difference frequency generation which is purely an optical phenomenon where no electrical energy is required. So it has greater speed of operation and uses less power. The state of information is represented by three different frequency conditions which have due advantage compared to other kind of encoding technique commonly used. © 2012 Elsevier GmbH. All rights reserved.

A memory unit is a sequential logic which is an essential part of a computational machine. Realization of fast optical memory units is very challenging. In this communication the authors propose a method of implementation of different frequency encoded flip flops JK, D and T exploiting semiconductor optical amplifier based polarization rotation, filtering and frequency conversion. The main advantage of the frequency encoding technique is that it is free from intensity loss dependent problem and provides ultra fast speed of operation. © 2012 Optical Society of India.

All optical logic gates exploiting polarization independent four wave mixing in semiconductor optical amplifier (SOA), filtering property of ADD/DROP multiplexer (ADM) and non-linearity in reflective semiconductor optical amplifier (RSOA) have been proposed. The logic gates proposed are polarization independent which ensures hardware simplicity and greater speed. The all optical frequency encoded logic gates NOT, OR, NOR, AND, NAND, X-OR, X-NOR are implemented which are very useful in optical computing ad signal processing, cryptography, etc. The logic gates proposed have the advantages that there is no intensity loss dependent problem, and are polarization and temperature insensitive. © 2010 Elsevier GmbH.

A novel frequency encoded all optical half adder, half subtractor and full adder are proposed. The implementation is ultrafast one and the frequency encoding makes it intensity loss dependent problem free. The use of polarization insensitive four-wave mixing makes the design polarization independent and the hardware simple. The frequency conversion by the reflective semiconductor optical amplifiers (RSOA) makes the design faster compared to other semiconductor optical amplifiers (SOA) based design. © 2010 Elsevier GmbH. All rights reserved.

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