NOR Logic Operations Research Articles

A scheme of developing frequency encoded tristate-optical logic operations using semiconductor optical amplifier

The ever increasing demand for very fast and agile optical networks requires very fast execution of different optical and logical operations as well as large information handling capacities at the same time. In conventional binary logic based operations the information is represented by two distinct states only (0 and 1 state). It limits the large information handling capacity and speed of different arithmetic and optical logic operations. Tristate based logic operations can be accommodated with optics successfully in data processing, as this type of operation can enhance the speed of operation as well as increase the information handling capacity. Here in this communication the author proposes a new method to implement all-optical different logic gates with tristate logic using the frequency-encoding principle. The frequency encoding/decoding based optical communication has distinctly great advantages because the frequency is the fundamental character of an optical signal and it preserves its identity throughout the communication. The principle of the rotation of the state of polarization of a probe beam through semiconductor optical amplifier (SOA), frequency routing property of an optical add/drop multiplexer (AD) and high frequency conversion property of reflecting semiconductor optical amplifiers (RSOA) have been exploited here to implement the desired AND, OR, NAND and NOR logic operations with tristate logic.

Reconfigurable All-Optical Logic Gates for Multi-Input Differential Phase-Shift Keying Signals: Design and Experiments

Differential phase-shift keying (DPSK) signals are promising candidate for the long-haul transmission systems. However, the development of the all-optical signal processing techniques for the DPSK signals is still in its infancy, especially the all-optical logic operations. In this work, a general scheme for reconfigurable logic gates for multi-input DPSK signals with integration possibility is proposed. Benefiting from the optical logic minterms developed by two kinds of optical devices, i.e., optical delay interferometers and semiconductor optical amplifiers (SOAs), target logic functions can be realized by combining specific minterms together. The scheme is reconfigured by changing the phase control of the delay interferometers or the input wavelengths. The latter approach was adopted in the experimental trials. Although the outputs of the scheme are on-off keying (OOK) signals, the data format is compatible with all-optical decision circuits where OOK format is preferred. Two- and three-input experiments are carried out at 20 Gbit/s with nonreturn-to-zero DPSK signals. Various logic operations are demonstrated, including full sets of two- and three-input minterms, AND, NOR, XOR, and XNOR logic operations where the AND and NOR logic are derived simultaneously and the XOR and XNOR logic are convertible. The optical SNR as well as the Q-factor of the two- and three-input results are measured and compared. It shows that the input powers to the SOAs are critical in achieving good extinction ratio and the Q-factor of logic results degrades when several minterms are combined. The recovery time of the SOAs need to be optimized as well. Finally, the scaling issues of the scheme are discussed.

Method of implementing frequency-encoded NOT, OR and NOR logic operations using lithium niobate waveguide and reflecting semiconductor optical amplifiers

Optics has already proved its strong potentiality for the conduction of parallel logic, arithmetic and algebraic operations. In the last few decades several all-optical data processors were proposed. To implement these processors different data encoding/decoding techniques have been reported. In this context, polarization encoding technique, intensitybased encoding technique, tristate and quaternary logic operation, multivalued logic operations, symbolic substitution techniques etc. may be mentioned. Very recently, frequency encoding/decoding technique has drawn interest from the scientific community. Frequency is the fundamental character of any signal; and it remains unaltered in reflection, refraction, absorption etc. during the propagation and transmission of the signal. This is the most important advantage of frequency encoding technique over the conventional encoding techniques. In this communication the authors propose a new scheme for implementing NOT, OR and NOR logic operations. For this purpose co-propagating beams having different frequencies in C-band (1535–1560 nm) have been used for generating cascaded sum and difference frequency, exploiting the nonlinear response character of periodically poled LiNbO3 waveguide. The cross-gain modulation property of the semiconductor optical amplifier (SOA) and the wavelength conversion property of the reflecting semiconductor optical amplifiers (RSOA) are exploited here to implement the desired optical logic and arithmetic operations.

Magnetic logic devices composed of permalloy dots

Magnetic logic devices have been investigated by micromagnetics simulation and experiment. The simulation shows that the magnetic logic devices composed of 4 elliptical permalloy dots perform both the NAND and NOR logic operations. The experiments indicate that the distance between adjacent dots must be shorter than 50 nm and 70 nm along the long axis and the short axis of the dots, respectively. The micro-fabricated test devices show the above logic operations.

Multiple Logic Fluorescent Thermometer System Based on N-Isopropylmethacrylamide Copolymer Bearing Dicyanomethylene-4H-pyran Moiety

The development of polymeric systems that can integrate individual basic logic gates into combinational circuits has been extremely interesting as smart materials. A novel thermometer fluorescent sensor poly(NIPMAM-co-MDCPDP) consisting of N-isopropylmethacrylamide (NIPMAM) as a thermoresponsive unit and dicyanomethylene-4H-pyran derivative as a dipolar-sensitive fluorophore unit was designed. Poly(NIPMAM-co-MDCPDP) performs fluorescence quenching merely by coordination with Cu2+ ions or increasing temperature in neutral or acid aqueous solution. The ON−OFF fluorescence response of poly(NIPMAM-co-MDCPDP) is driven by a temperature-induced phase transition from coil to globule and the capture of Cu2+ ions, resulting in a decrease of the ICT efficiency in neutral solution. The combinational serial NOR logic operation as well as two INHIBIT logic gates was constructed with three inputs: various pH, temperature change, and Cu2+ ions. The proposed combinational logic circuits play a key role in mimicking compr...

Novel Bisthienylethenes Containing Naphthalimide as the Center Ethene Bridge: Photochromism and Solvatochromism for Combined NOR and INHIBIT Logic Gates

Two novel photochromic bisthienylethene derivatives BTE-NA1 and BTE-NA2 with a six-membered aryl ring of naphthalimide fluorescent moiety as the center ethene bridging unit were synthesized and fully characterized by 1H NMR, 13C NMR, and HRMS. They exhibit considerably high cyclization quantum yield and good fatigue resistance. Interestingly, the fluorescence of BTE-NA1 arising from the naphthalimide unit could be well modulated by photochromism and solvatochromism. Quantum chemical calculations were carried out to study their geometrical, electronic, and optical properties, which were in good accordance with the experimental data. Furthermore, a combined NOR and INHIBIT logic operation based on BTE-NA1 has been successfully mimicked with fluorescence changes as outputs.

Design of molecular logic devices based on a programmable DNA-regulated semisynthetic enzyme.

In living cells, enzyme activity and function are tightly regulated at multiple levels through information transfer processes programmed by evolution to respond appropriately to patterns of extracellular stimuli.[1] By contrast, methods for controlling enzyme activity in vitro are typically non-informational[2] and hence not readily amenable to programming.[3] We report a general chemical encoding strategy for fashioning natural enzymes into informational and thus programmable complexes that, along with a range of programming options, can be used to modulate enzyme activity in vitro according to user-defined parameters and inputs. The approach converts an enzyme and its inhibitor into an intrasterically inactivated enzyme complex subject to DNA-directed allosteric activation.[4] An enzyme programmed in this fashion can utilize DNA inputs to selectively and reversibly turn catalytic activity on or off generating what constitutes temporally dependent output signals, read as the amounts or rates of product formed. Moreover, DNA-encoded intrasterically regulated enzymes can be readily programmed to execute specific tasks as highlighted by systems capable of performing AND, OR, and NOR logic operations and operating as sensitive PCR-independent gene diagnostic probes. Programmable enzymes are expected to impact a range of applications including molecular computation, construction of in vitro biosynthetic networks, and in biomedical settings such as diagnostics and enzyme therapeutics.

Semiconductor nonlinear etalons

Previous observations of optical bistability in nonlinear etalons of ZnS, CuCl and GaAs are summarized. Emphasis is placed upon recent results in GaAs: similar room-temperature optical bistability at powers under 10 mW in bulk and multiple quantum-well etalons; room-temperature bistability achieved with a diode laser as a light source; NOR and other logic operations; optical fibre signal regeneration and continuous wave operation.