NOT OR Research Articles

320 Gb/s all-optical logic operations based on two-photon absorption in carrier reservoir semiconductor optical amplifiers

When a train of optical pulses is injected, two-photon absorption (TPA)-induced pumping results in significant and fast gain and phase shifts in the carrier reservoir semiconductor optical amplifier (CR-SOA). Therefore, in this work, the effect of TPA on all-optical (AO) exclusive-OR (XOR), AND, NOT-OR (NOR), OR, NOT-AND (NAND), and exclusive-NOR (XNOR) logic operations using CR-SOAs is theoretically implemented for the first time at 320 Gb/s. The XOR, AND, NOR, NAND, and XNOR logic gates are implemented using the Mach-Zehnder interferometer, which has two symmetrical CR-SOAs in each of its two arms, whereas the OR logic gate is produced by combining a CR-SOA with a delayed interferometer. The quality factor (QF) and the associated bit error rate (BER) metrics are employed to evaluate the operations’ performance. The obtained simulation results indicate that when exploiting TPA in CR-SOAs the target Boolean functions can be executed with QF and BER that are more than acceptable than without TPA at a high speed up to 320 Gb/s. Various circuits of enhanced logic functionality, such as AO half-adder, latches, comparator, half-subtractor, and encoder can be implemented by combing the presented AO gates and hence exploiting the ultrafast TPA-induced gain and phase changes in CR-SOAs. Furthermore, the potential of CR-SOAs as nonlinear elements is systematically and thoroughly established for a wide suite of AO logic operations.

Optical Logic Operation Encryption on ZnTe Flake

AbstractLogic operation encryption is emerging as a novel cryptographic mode, protecting logic operation from being attacked and tampered, and is a modern extension of conventional encryption system. However, the existing encryption methods are not conducive to the logic operation encryption due to the complexity, signal mode, and non‐adjustability of their design. Herein, an advanced logic operation encryption method is designed via the photoluminescence ratio of ZnTe, and the electrically and optically switchable NAND (Not AND) and NOR (Not OR) encryption based on this method is implemented. Two photoluminescence emissions can be selectively regulated by the gate voltage and excitation laser based on the different responses of band‐edge emission and defect emission. This novel approach will shed light on the development of high‐security encryption and computer information protection.

Reflective semiconductor optical amplifiers-based all-optical NOR and XNOR logic gates at 120 Gb/s

In this paper, we reported a reflective semiconductor optical amplifier (RSOA), in which the input light propagates and reflects back to the input port after amplifying twice through its active region. The RSOA produces higher gain and lower noise figure at low drive currents with energy-efficient than the conventional SOAs. The RSOA’s features are employed herein to numerically analyze the ultrafast performance of the all-optical NOT-OR (NOR) and Exclusive-NOR (XNOR) logic gates using a dual-RSOAs-based scheme at 120 Gb/s. A comparison between RSOAs- and conventional SOAs-based AO NOR and XNOR gates is made by studying the quality factor (QF) against the critical operational parameters when the effects of the amplified spontaneous emission and the operating temperature are included to obtain more realistic results. Compared to conventional SOAs, the RSOAs allow to achieve more acceptable performance at 120 Gb/s and to render the implementation of the NOR and XNOR gates more feasible.

All-optical multifunctional AND, NOR, and XNOR logic gates using semiconductor optical amplifiers

We theoretically analyze the performance of all-optical multifunctional AND, NOT-OR (NOR), and exclusive-NOR (XNOR) logic gates at 80 Gb s−1 using return-to-zero data format in a compact scheme based on semiconductor optical amplifiers (SOAs). The AND logic gate is formed by incorporating two SOAs in a Mach–Zehnder interferometer and the NOR logic gate is formed using a single SOA followed by a series delayed interferometer. Then an additional logic gate, XNOR, is realized by by the combination of the AND and NOR output logic channels. Therefore, three logic operations are performed using a compact scheme within few resources. The quality factor (QF) of the considered Boolean functions against the key operational parameters of the input data and SOA is examined, considering the effects of the amplified spontaneous emission, operating temperature, and phase noise for more realistic results. The results of Wolfram Mathematica show that three logic functions, AND, NOR, and XNOR, can simultaneously be realized at 80 Gb s−1 using the employed compact scheme with high QF.

All-optical OR and NOR gates using quantum-dot semiconductor optical amplifiers-assisted turbo-switched Mach-Zehnder interferometer and serially delayed interferometer at 1 Tb/s

The turbo-switch (TS) has proven to enhance the speed of the conventional semiconductor optical amplifier (SOA) up to four times better than the single SOA architecture. A novel performance of all-optical (AO) OR and NOT-OR (NOR) logic gates using TS Mach-Zehnder interferometer (TSMZI) combined with the ultrafast quantum-dot (QD) SOAs and followed by a serially delayed interferometer (DI) is numerically analyzed and investigated at 1 Tb/s. For comparison, the results have been obtained for AO OR and NOR Boolean functions using a DI after QDSOAs-based TSMZI, QDSOAs-based TSMZI, and QDSOAs-based conventional MZI. The achieved results indicate that placing a DI in series with the QDSOAs-TSMZI renders acceptable of OA OR and NOR operations at 1 Tb/s than QDSOAs-TSMZI and QDSOAs-MZI, where this achievement is not possible.

Numerical modeling of photonic crystal semiconductor optical amplifiers-based 160 Gb/s all-optical NOR and XNOR logic gates

A photonic crystal (PC) is a periodic optical nanostructure typically containing ordered arrays of holes that confine and control the motion of photons. Moreover, PC strongly modifies the dispersion relationship. The conventional semiconductor optical amplifier (SOA), on the other hand, is an attractive nonlinear element due to its strong nonlinearity, compactness, power efficiency, and integration potential with other optoelectronic devices. Thus, we combine the unique features of PC with those of SOA to numerically model ultrafast all-optical NOT-OR (NOR) and exclusive-NOR (XNOR) logic gates at 160 Gb/s. A comparison is made between PCSOAs and conventional SOAs schemes through examining the variation of the quality factor (QF) against the key operational parameters, including the effects of the amplified spontaneous emission and operating temperature, in order to obtain more realistic results. The obtained results confirm that the considered logic operations using PCSOAs are capable of operating at 160 Gb/s with higher QF than when having conventional SOAs.

All-optical NOR and XNOR logic gates at 2 Tb/s based on two-photon absorption in quantum-dot semiconductor optical amplifiers

Two-photon absorption (TPA) is a nonlinear absorption process in semiconductors, creating a fast phase change in a low-intensity probe beam. Placing quantum-dots (QDs), on the other hand, in the active region of semiconductor optical amplifiers (SOAs) results in SOAs shorter carrier recovery time and lower gain saturation. Thus, in this article, the physical advantages of both TPA and QDs have been combined to numerically investigate the performance of all-optical NOT-OR (NOR) and exclusive-NOR (XNOR) logic gates, incorporating in Mach–Zehnder interferometers at a data rate of 2 Tb/s. The output quality factor (QF) of the considered Boolean functions against the key operational parameters is assessed and examined, including the impact of amplified spontaneous emission in order to obtain more realistic results. The overall QF in the presence of TPA is always higher than that without TPA.

High Mobilities in Layered InSe Transistors with Indium-Encapsulation-Induced Surface Charge Doping.

Tunability and stability in the electrical properties of 2D semiconductors pave the way for their practical applications in logic devices. A robust layered indium selenide (InSe) field-effect transistor (FET) with superior controlled stability is demonstrated by depositing an indium (In) doping layer. The optimized InSe FETs deliver an unprecedented high electron mobility up to 3700 cm2 V-1 s-1 at room temperature, which can be retained with 60% after 1 month. Further insight into the evolution of the position of the Fermi level and the microscopic device structure with different In thicknesses demonstrates an enhanced electron-doping behavior at the In/InSe interface. Furthermore, the contact resistance is also improved through the In insertion between InSe and Au electrodes, which coincides with the analysis of the low-frequency noise. The carrier fluctuation is attributed to the dominance of the phonon scattering events, which agrees with the observation of the temperature-dependent mobility. Finally, the flexible functionalities of the logic-circuit applications, for instance, inverter and not-and (NAND)/not-or (NOR) gates, are determined with these surface-doping InSe FETs, which establish a paradigm for 2D-based materials to overcome the bottleneck in the development of electronic devices.

High-Speed Programming Not-OR Flash Memory Cells With Titanium Disilicide Drain

A Not-OR (NOR) flash memory cell using a titanium disilicide (TiSi2) drain was designed to increase programming speed and driving current. This NOR flash memory cell with a TiSi2 drain was proposed on the basis of the fundamental structure of conventional NOR flash memory cells with a length of 90 nm. The programming speed and driving current of the NOR flash memory cell with a TiSi2 drain were simulated using T-SUPREM4 and MEDICI. The simulation results showed that the heavily doped carriers existing in the TiSi2 drain can be used to increase the programming speed of the NOR flash memory cell and that a decrease in source/drain series resistance utilizing the silicide in the NOR flash memory cell with a TiSi2 drain helps increase driving current density.

Novel Pyrene‐armed Calix[4]arenes through Triazole Connection: Ratiometric Fluorescent Chemosensor for Zn2+ and Promising Structure for Integrated Logic Gates

AbstractTwo novel pyrene‐armed calix[4]arenes by triazole connection were synthesized using "click" chemistry. Compound 1 with two pyrene subunits appended to the lower rims of the calix[4]arene shows ratiometric fluorescence response toward Zn2+, and selective fluorescence quenching toward heavy metal ions such as Cu2+, Hg2+ and Pb2+; while compound 2 with one pyrene subunit exhibits significant fluorescence quenching toward Cu2+ and moderate quenching behaviour toward Hg2+. By utilizing the different fluorescence behavior of 1 toward Zn2+ and Cu2+, inhibition (INH) and not or (NOR) logic gates were established.

Single-electron-based flexible multivalued logic gates

Single-electron transistor (SET)-based multivalued (MV) not-AND (NAND) and not-OR (NOR) logic cells were implemented on a silicon-on-insulator chip. Depending on the ways of connecting two SETs with a field-effect transistor, the voltage transfer characteristics show typical NAND or NOR gate functions for various input voltages, which are binary, MV, and binary-MV mixed. Moreover, the switching functionality of our NAND (NOR) can convert to OR (AND) operation by simply adjusting their initial input voltages. These flexible two-input logic gates are expected to provide four basic arithmetic cells for the SET MV logic gate family.

All‐Photonic Molecular XOR and NOR Logic Gates Based on Photochemical Control of Fluorescence in a Fulgimide–Porphyrin–Dithienylethene Triad

AbstractA molecular triad consisting of a porphyrin linked to two photochromes, a fulgimide, and a dithienylethene, is synthesized and studied. When both photochromes are in their visible‐light‐absorbing forms, excitation of the fulgimide at 470 nm initiates a two‐step singlet energy‐transfer relay wherein excitation migrates first to the porphyrin and then to the dithienylethene. Photoisomerization of the dithienylethene to the open form using visible light prevents the second step, and excitation ultimately resides on the porphyrin, which fluoresces. Photoisomerization of the fulgimide eliminates significant absorption by the molecule at 470 nm, and consequently porphyrin excitation by energy transfer. Photoisomerization of each photochrome may be preferentially achieved, allowing access to all four isomeric states of the molecule. These states correspond to the outputs of logic gates, allowing solutions of the triad to perform either NOT‐OR (NOR) or exclusive OR (XOR) functions using only optical inputs and outputs.

A Photorefractive Setup for Parallel Not-OR and Not-AND Operations with Mutually Incoherent Light

We have demonstrated experimentally that optical Not-OR (NOR) and Not-AND (NAND) operations can be done with a single setup. The setup is capable of processing parallel inputs. Two barium titanate (BaTiO3) crystals are used in the setup and photorefractive effects are employed. Instead of using the interference between the two input signals to be processed or the so called local incoherent erasing, the setup works on the phenomenon of self-pumped phase conjugation and the suppression of it by the input signals in ordinarily polarized state. In this way, the two input channels can be mutually incoherent.

Computing with Lipids, Proteins, and Ions

Computing with Lipids, Proteins, and Ions