Ali Shahidinejad

Characterisation of bifurcation and chaos in silicon microring resonator

This study investigates the non-linear behaviours of light known as bifurcation and chaos during the propagation of light inside a non-linear silicon microring resonator (SMRR). The aim of the research is to use the non-linear behaviour of light to control the bifurcation and chaos of SMRR, which are used in engineering, biological and security systems. Bifurcation and chaos control deals with the modification of bifurcation characteristics of a parameterised non-linear system by a designed control input. The parameters of the SMRR cause bifurcation to happen in smaller round-trips among the total round-trip of 20 000 or input power. Effective parameters such as the refractive indices of a silicon waveguide, coupling coefficients (κ) and the radius of the ring (R) can be selected properly to control the non-linear behaviour. Simulated results show that rising non-linear refractive indices, coupling coefficients and radii of the SMRR lead to descending input power and round-trips when bifurcation occurs. Therefore bifurcation behaviour can be seen at a lower input power of 44 W, where the non-linear refractive index is n2=3.2×10−20 m2/W. The smallest round-trips of 4770 and 5720 can be seen for the R=40 µm and κ=0.1, respectively.

Generation of potential wells used for quantum codes transmission via a TDMA network communication system

This paper proposes a technique of quantum code generation using optical tweezers. This technique uses a microring resonator made of nonlinear fibre optics to generate the desired results, which are applicable to Internet security and quantum network cryptography. A modified add/drop interferometer system called PANDA is proposed, which consists of a centred ring resonator connected to smaller ring resonators on the left side. To form the multifunction operations of the PANDA system-for instance, to control, tune and amplify-an additional Gaussian pulse is introduced into the add port of the system. The optical tweezers generated by the dark soliton propagating inside the PANDA ring resonator system are in the form of potential wells. Potential well output can be connected to the quantum signal processing system, which consists of a transmitter and a receiver. The transmitter is used to generate high-capacity quantum codes within the system, whereas the receiver detects encoded signals known as quantum bits. Therefore, an entangled photon pair can be generated and propagated via an optical communication link such as a time division multiple access system. Here, narrower potential wells with a full-width half-maximum of 3.58 and 9.57nm are generated at the through and drop ports of the PANDA ring resonator system, respectively, where the amplification of the signals occurs during propagation inside the system. Copyright

Multi optical Soliton generated by PANDA ring resonator for secure network communication

In this study, new system of quantum cryptography for network communication is proposed. Multi optical Soliton can be generated and propagate via a nonlinear modified add/drop interferometer system incorporated with a time division multiple access (TDMA) system wherein the transportation of quantum codes is performed. To increase the channel capacity and security of the signals, the PANDA ring resonator is proposed. Chaotic output signals from the PANDA ring resonator are input into the add/drop filter system. Chaotic signals can be filtered by using the add/drop filter system in which multi dark and bright solitons can be obtained and used to generate entangled quantum codes for internet security. In this study soliton pulses with FWHM and FSR of 325 pm and 880 nm are generated, respectively, where the Gaussian pulse with a centre wavelength of 1.55 μm and power of 600 mW is input into the system.

MRR quantum dense coding for optical wireless communication system using decimal convertor

In this study, simply two systems consist of series of microring resonators (MRRs) and a add/drop filter are used to generate a large bandwidth signal as localized multi wavelength, applicable for quantum dense coding (QDC) and continuous variable encoding generation using incorporated system. This technique uses the Kerr nonlinear type of light in the MRR to generate multi wavelength for desired application especially in internet security and quantum network cryptography. Quantum dense encoding can be perform by output signals of selected wavelengths which are incorporated to a polarization control system in which dark and bright optical soliton pulses with different time slot are generated. Generated dark and bright optical pulses can be converted into digital logic quantum codes using a decimal convertor system in which transmission of secured information are perform via a wireless network communication system. Results show that multi soliton wavelength, ranged from 1.55μm to 1.56μm with FWHM and FSR of 10 pm and 600 pm can be generated respectively.

Generation of discrete frequency and wavelength for secured computer networks system using integrated ring resonators

In this study, a system of discrete optical pulse generation via a series of microring resonator (MRR) is presented. Chaotic signals can be generated by an optical soliton or a Gaussian pulse within a MRR system. Large bandwidth signals of optical soliton are generated by input pulse propagating within the MRRs, which can be used to form continuous wavelength or frequency with large tunable channel capacity. Therefore, distinguished discrete wavelength or frequency pulses can be generated by using localized spatial pulses via a networks communication system. Selected discrete pulses are more suitable to generate high-secured quantum codes because of the large free spectral range (FSR). Quantum codes can be generated by using a polarization control unit and a beam splitter, incorporating to the MRRs. In this work, frequency band of 10.7 MHz and 16 MHz and wavelengths of 206.9 nm, 1448 nm, 2169 nm and 2489 nm are localized and obtained which can be used for quantum codes generation applicable for secured networks communication.

Network system engineering by controlling the chaotic signals using silicon micro ring resonator

We investigate nonlinear behaviors of light known as bifurcation and chaos within a nonlinear silicon microring resonator (SMRR). The research is used to controlling SMRRs behaviors such as chaos applicable in security coding systems. The variable parameters affect the bifurcation to be happened in smaller roundtrip among total round trip of 20000 or input power. Simulated Results show that rising of the nonlinear refractive indices, coupling coefficients and radius of the SMRR leads to descending in input power and round trips wherein the bifurcation occurs. As result, bifurcation or chaos behaviors are seen at lower input power of 44 W, where the nonlinear refractive index is n2 = 3.2×10-20 m2/W. Smallest round trips of 4770 and 5720 can be seen for the R = 40 μm and k = 0.1 respectively. The controlled chaotic signals from the SMRR are passing through a polarizer beam splitter to generate quantum binary codes which are used in wireless network communication.

Design of First Adder/Subtractor Using Quantum-Dot Cellular Automata

Quantum-dot cellular automata (QCA) is an emerging nanotechnology that provides faster speed, smaller size and lower power consumption compared to the current transistor-based technology. Adder/ subtractor is a useful component for the design of many computation systems and functional circuits. This paper proposes a practical XOR design in QCA. Then the first adder/subtractor circuit in QCA is designed and simulated using the proposed XOR design. Results of simulation were carried out using QCADesigner.

A Novel Quantum-Dot Cellular Automata XOR Design

Quantum-dot cellular automata (QCA) is an emerging nanotechnology that promises faster speed, smaller size, and lower power consumption compared to the transistor-based technology. Moreover, XOR is a useful component for the design of many logical and functional circuits. This paper proposes a novel and efficient QCA XOR design. The proposed XOR design has been compared to a few recent designs in terms of area, speed and complexity. Comparison of results illustrates significant improvements in our design as compared to traditional approaches. Also simulation proves that the proposed XOR design is completely robust and more sustainable to high input frequency as compared to other designs. This robustness is highly significant when this component is applied for realizing larger designs.