Multifunctional Logic Research Articles

Simulation of Nanoscale Multifunctional Interferometric Logic Gates Based on Coupled Metal Gap Waveguides

A novel design of ultrasmall multifunctional Boolean logic gates is proposed in this letter. This interferometric logic device is based on the coupled metal waveguides. This structure is a theoretical analysis, and logic performances are proved by using the finite-difference time-domain method. The single device can perform individually four different kinds of basic functions: and, or, xor, and not operations. The device with an extremely small feature size is an attractive candidate for high density nano-photonic integrated circuits.

Sensor activity and logic behaviour of PET based dihydroimidazonaphthalimide diester

An ester terminated dihydroimidazonaphthalimide as multi-functional logic device is presented. Due to the optical changes as a function of pH this simple molecule is able to act as a molecular pH metre, a digital comparator and a half-adder. It was demonstrated that the dihydroimidazonaphthalimide comparator could be used as a fundamental element of an optical device for control of pH windows. Also, the ability of the device to detect metal ions in DMF and in water/DMF (3:1, v/v) at different pHs has been evaluated by monitoring the changes of its fluorescence intensity. Among the tested metal ions (Cd2+, Co2+, Cu2+, Fe3+, Ni2+, Pb2+, Zn2+, Bi3+, Hg2+ and Ag+) only Fe3+ and Bi3+ were efficiently detected. In water/DMF (3:1, v/v) XOR and XNOR logic gates are presented using pH and Fe3+ as chemical inputs based on encoding binary digits of logical conventions.

Optically switchable transistor via energy-level phototuning in a bicomponent organic semiconductor

Organic semiconductors are suitable candidates for printable, flexible and large-area electronics. Alongside attaining an improved device performance, to confer a multifunctional nature to the employed materials is key for organic-based logic applications. Here we report on the engineering of an electronic structure in a semiconducting film by blending two molecular components, a photochromic diarylethene derivative and a poly(3-hexylthiophene) (P3HT) matrix, to attain phototunable and bistable energy levels for the P3HT's hole transport. As a proof-of-concept we exploited this blend as a semiconducting material in organic thin-film transistors. The device illumination at defined wavelengths enabled reversible tuning of the diarylethene's electronic states in the blend, which resulted in modulation of the output current. The device photoresponse was found to be in the microsecond range, and thus on a technologically relevant timescale. This modular blending approach allows for the convenient incorporation of various molecular components, which opens up perspectives on multifunctional devices and logic circuits.

Reconfigurable all-optical dual-directional half-subtractor for high-speed differential phase shift keying signal based on semiconductor optical amplifiers

All-optical digital logic elementary circuits are the building blocks of many important computational operations in future high-speed all-optical networks and computing systems. Multifunctional and reconfigurable logic units are essential in this respect. Employing the demodulation properties of delay interferometers for input differential phase shift keying signals and the gain saturation effect in two parallel semiconductor optical amplifiers, a novel design of 40 Gbit/s reconfigurable all-optical dual-directional half-subtractor is proposed and demonstrated. All output logic results show that the scheme achieves over 11=dB extinction ratio, clear and wide open eye diagram, as well as low polarization dependence (< 1 dB), without using any additional input light beam. The scheme may provide a promising candidate for future ultrafast all-optical signal processing applications.

A differential ICT based molecular probe for multi-ions and multifunction logic circuits

This paper presents anthraquinone and benzimidazole based hybrid molecular architect as the state of the art for multifunctional molecular logic circuits. The moleculator exhibits differential output behavior towards F(-), Zn(2+) and Cu(2+) ions to provide opportunities for elaboration of XOR, INHIBIT, XNOR, AND, OR, NOR, logic functions and their integrated logic functions half-adder, half-subtractor and comparator within a single molecule. These integral logic functions can be reprogrammed by self-annihilation or by another additional input in the same cell. This single molecule behaves uniquely where different logic functions can be operated and reset by using different inputs and outputs.

Multi-addressable photochromic terarylene containing benzo[b]thiophene-1,1-dioxide unit as ethene bridge: multifunctional molecular logic gates on unimolecular platform

A photochromic terarylene (BTO) containing a benzo[b]thiophene-1,1-dioxide unit as a central ethene bridge was synthesized and characterized, and exhibits good thermal stability and fatigue resistance both in solution and bulk crystals. When triggered by chemical ions, protons and light, BTO can behave as an absorbance and fluorescence switch, leading to a multi-addressable system. The different color changes of BTO upon adding Cu2+ and Hg2+ ions arise from the relative binding stoichiometry and the association affinities. The titration of the Job plot indicates that BTO forms a 1:1 complex with Hg2+, whereas in the case of Cu2+, the Job plot exhibits a maximum at about a 0.33 mole fraction, indicating that BTO forms a 2:1 complex with Cu2+. Moreover, the conversion yield of BTO can be modulated with chemical ions. Impressively, an increase in conversion yield was observed by adding Hg2+ to the solution of BTO, that is, the conversion yield and cyclization quantum yield are increased from 77.6% and 28.5% (for BTO only) to 99.8% and 43.1% (BTO-Hg2+), respectively. A series of molecular logic gates such as a half-adder, half-subtractor, 4-to-2 encoder, 2-to-4 decoder, and a 1:2 demultiplexer were constructed on the unimolecular platform by employing absorption and emission properties at different wavelengths as outputs, with the appropriate combination of chemical and photonic stimuli, which is a further step towards data processing on the molecular level with potential applications in sensing and labeling as well as for data manipulation.

Optical programmable Boolean logic unit

Logic units are the building blocks of many important computational operations likes arithmetic, multiplexer-demultiplexer, radix conversion, parity checker cum generator, etc. Multifunctional logic operation is very much essential in this respect. Here a programmable Boolean logic unit is proposed that can perform 16 Boolean logical operations from a single optical input according to the programming input without changing the circuit design. This circuit has two outputs. One output is complementary to the other. Hence no loss of data can occur. The circuit is basically designed by a 2×2 polarization independent optical cross bar switch. Performance of the proposed circuit has been achieved by doing numerical simulations. The binary logical states (0,1) are represented by the absence of light (null) and presence of light, respectively.

Reconfigurable Graphene Logic Device Based on Tilted P-N Junctions

ABSTRACTIn this paper, we introduce a novel reconfigurable graphene logic based on graphene p-n junctions. In this logic device, switching is accomplished by using co-planar split gates that modulate the properties that are unique to graphene, including ambipolar conduction, electrostatic doping, and angular dependent carrier reflection. In addition, the use of these control gates can dynamically change the operation of the device, leading to reconfigurable multi-functional logic. A device model is derived from carrier transmission probability across the p-n junction for allowing quantitative comparison to CMOS logic. Based on this model, we show that the proposed graphene logic has significant advantages over CMOS gate in terms of area, delay, power, and signal restoration. Furthermore, the device utilizes a large graphene sheet with minimal patterning, allowing feasible integration with CMOS circuits, for potential CMOS-graphene hybrid circuits.

Reconfigurable Graphene Logic

In this paper, we introduce a novel reconfigurable graphene logic based on graphene p-n junctions. In this logic device, switching is accomplished by using co-planar split gates that modulate the properties that are unique to graphene, including ambipolar conduction, electrostatic doping, and angular dependent carrier reflection. In addition, the use of these control gates can dynamically change the operation of the device, leading to reconfigurable multi-functional logic. A device model is derived from carrier transmission probability across the p-n junction for allowing quantitative comparison to CMOS logic. Based on this model, we show that the proposed graphene logic has significant advantages over CMOS gate in terms of area, delay, power, and signal restoration. Furthermore, the device utilizes a large graphene sheet with minimal patterning, allowing facile integration with CMOS circuits, for potential CMOS-graphene hybrid circuits.

Ultrasmall optical logic gates based on silicon periodic dielectric waveguides

An ultrasmall silicon periodic dielectric waveguides-based multimode interference all-optical logic gate has been proposed. The device consists of three 205 nm wide single-mode input waveguides, a 1.1 μm wide and 5.5 μm long multimode interference waveguide, and three 205 nm wide single-mode output waveguides. The total length and width of the device are 13.7 μm and 3.2 μm, respectively. By changing the states of the input optical signals and/or control signals launched into the device, multifunctional logic functions including OR, NAND, NOR, and NOT gates are performed, and each logic function can be realized at a specific output waveguide in accordance with the launched control signals. The ultrasmall multifunctional logic device has potential applications in high density photonic integrated circuits.

SOA-Based Ultrafast Multifunctional All-Optical Logic Gates With PolSK Modulated Signals

In this paper, we propose a novel scheme for ultrafast multifunctional all-optical logic gates, which can achieve not only simple logic gates including AND, NOR, Smacr 1Smacr2,Smacr1Smacr2,XNOR, and XOR but also complex logic gates including half adder, half subtracter, decoder, and comparer based on four-wave mixing in semiconductor optical amplifiers (SOAs) with polarization-shift-keying (PolSK) modulated signals. A comprehensive polarization-dependent broadband dynamic model of this kind of ultrafast multifunctional all-optical logic gates is presented. By numerical simulation, the multifunctional all-optical logic gates are theoretically realized at 40 Gbit/s. The effects of two input signal powers, injected current, frequency detuning, and polarization dependence of SOA on the output performance of the multifunctional all-optical logic gates are theoretically investigated in detail. The results indicate that this scheme is free of pattern effect due to using the PolSK modulation format. Moreover, the nice eye opening of the logic gates indicates the good performance of the proposed ultrafast multifunctional all-optical logic gates. This scheme is potential for applications in future high bit rate optical networks.

Operation properties of a reconfigurable photonic logic gate based on cross phase modulation in highly nonlinear fibers

The operation features of a 160 Gb / s reconfigurable all-optical logic gate based on cross phase modulation in highly nonlinear fibers are numerically investigated for six logic functions (XOR, OR, NAND, NOR, NOT, and AND). High bit rate operation is numerically demonstrated for a wide input signal wavelength range ( > 20 nm ). Performance enhancement of the proposed setup operating at 160 Gb / s for different signal wavelengths is exhibited by using a 2R regenerator based on the self-phase modulation effect in highly nonlinear fibers at the gate's output. The operation of the multi-functional logic gate is investigated considering either a pulsed or a continuous wave probe.

Logic Devices with Spin Wave Buses - an Approach to Scalable Magneto-Electric Circuitry

ABSTRACTWe analyze spin wave-based logic circuits as a possible route to building reconfigurable magnetic circuits compatible with conventional electron-based devices. A distinctive feature of the spin wave logic circuits is that a bit of information is encoded into the phase of the spin wave. It makes possible to transmit information as a magnetization signal through magnetic waveguides without the use of an electric current. By exploiting sin wave superposition, a set of logic gates such as AND, OR, and Majority gate can be realized in one circuit. We present experimental data illustrating the performance of a three-terminal micrometer scale spin wave-based logic device fabricated on a silicon platform. The device operates in the GHz frequency range and at room temperature. The output power modulation is achieved via the control of the relative phases of two input spin wave signals. The obtained data shows the possibility of using spin waves for achieving logic functionality. The scalability of the spin wave-based logic devices is defined by the wavelength of the spin wave, which depends on the magnetic material and waveguide geometry. Potentially, a multifunctional spin wave logic gate can be scaled down to 0.1μm2. Another potential advantage of the spin wave-based logic circuitry is the ability to implement logic gates with fewer elements as compared to CMOS-based circuits in achieving same functionality. The shortcomings and disadvantages of the spin wave-based devices are also discussed.

All-Optical Multifunctional Logic Gates for Image Information Using Photorefractive Two-Wave Mixing

In this paper, we propose all-optical multifunctional logic gates for image information using photorefractive (PR) two-wave mixing. The optical setup is simply configured compared with the other all-optical logic gates for image information. The XOR-, OR-, and AND-operation are all-optically performed in the same optical setup through the transitional response of the PR medium. One can switch these logic operations simply by means of the on-off control of the signal and the pump beam illumination. We analyze the spatial distribution of beam intensity in these logic gates using a finite-difference beam propagation method (FD-BPM) and the crosstalk between adjoining pixels is examined from the result. We also experimentally verify that the XOR-, OR-, and AND-gates are realized in the same optical setup.

Realization of All-Optical XOR, NOR, and NAND Gates in Single Format by Using Semiconductor Optical Amplifiers

By using the cross gain modulation (XGM) characteristics of semiconductor optical amplifiers (SOAs), multi-functional all-optical logic gates including XOR, NOR, and NAND gates are successfully demonstrated at 10 Gbps in single format. Numerical simulation is also performed by using the transmission-line laser model (TLLM), which is confirmed by using three SOAs experimentally. These combined all-optical multi-functional logic gates will provide more complex and complicated all-optical logic operations.

반도체 광증폭기를 이용한 다기능 전광 논리 소자의 설계 및 측정

반도체 광증폭기에 기반을 둔 이득포화특성을 이용하여 XOR, AND, OR 논리 게이트를 동시에 구현하는 다기능 전광 논리소자를 설계하고 구현하였다. 상용화된 프로그램인 VPI Component <TEX>$Maker^{TM}$</TEX>을 사용하여 시뮬레이션을 수행하였고 10 Gbit/s의 입력 신호를 사용하여 XOR, AND, OR 논리동작을 동시에 구현하는 다기능 전광 논리소자를 구현하였다. Using the cross-gain modulation (XGM) characteristics of semiconductor optical amplifiers (SOAs), multi-functional all-optical logic gates, including XOR, AND, and OR gates are successfully simulated and demonstrated at 10Gbit/s. A VPI component maker^TM simulation tool is used for the simulation of multi-functional all-optical logic gates and the10 Cbit/s input signal is made by a mode-locked fiber ring laser. A multi-quantum well (MQW) SOA is used for the simulation and demonstration of the all-optical logic system. Our suggested system is composed of three MQW SOAs, SOA-1 and SOA-2 for XOR logic operation and SOA-2 and SOA-3 for AND logic operation. By the addition of two output signals XOR and AND, all-optical OR logic can be obtained.

Logic gates with a single Hall bar heterostructure

A four-terminal Hall bar configuration is commonly used in the investigation of transport properties of modulation doped heterostructures. Here it is found that a single Hall bar can act as a multifunction logic gate if a gate electrode is patterned between the voltage probes. Four different logic functions can be obtained depending on the input voltage levels. Operation of all logic gates is demonstrated and merits of such gates with respect to conventional logic gates are discussed.

Realisation of all-optical multi-functional logic gates using semiconductor optical amplifiers

All-optical multi-functional logic gates by using the gain nonlinearity characteristics of cross-gain modulation in semiconductor optical amplifiers (SOAs) have been demonstrated. Using three SOAs, all-optical multi-functional logic gates for the simultaneous operations of AND, NOR and XNOR at 10 Gbit/s were successfully demonstrated.

Multifunctional logic modules consisting of elements with bilateral conductance

Multifunctional logic modules consisting of elements with bilateral conductance are proposed; when realizing Boolean formulas in the basis {&, v, !} consisting of at most six letters, these modules have no element redundancy. If the basis has more than six letters, then the redundancy does not exceed 33%.

Multifunctional photoelectrochemical logic gates based on a hemicyanine sensitized semiconductor electrode

A new amphiphilic hemicyanine dye, (E)-1,3,3-trimethyl-2-[2-(4-N-methyl-N-hexadecylaminophenyl)ethenyl]indolinium iodide (MHID) has been synthesized and successfully transferred onto a semiconducting transparent indium-tin oxide (ITO) electrode by Langmuir–Blodgett (LB) techniques. The photoelectric conversion properties of the dye MHID monolayer fabricated ITO electrode have been investigated in a three electrode photoelectrochemical cell. The observed photocurrent strongly depends on the applied electrode potential and the concentrations of the electron acceptors and donors. By using electron acceptors and (or) donors as input and photocurrent as output, respectively, we have fabricated this artificial photoelectrochemical system as multifunctional logic gates, corresponding to a series of logic operations (YES, OR, XOR and INHIBIT). Importantly, the gates of this photoelectrochemical system have been interconnected to demonstrate computation as a half-subtractor, with Eu3+ and hydroquinone (H2Q) as the two inputs and the cathodic photocurrent and the absolute value of the photocurrent as the two outputs, respectively.