Simulation and design of all-optical logic gates based on photonic crystals
- Autores: Oraman Yoosefi
- Directores de la Tesis: Ángel Rodríguez Martínez (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2021
- Idioma: español
- Materias:
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- Resumen
In this thesis,design and simulation of optical logic gases based on different photonics crystals presented to used in the electronics and telecommunication industries. Optical devices perform faster with higher efficiencies compare to the electrical device.The photonic crystal applications to achieve higher transmission power and contrast ratio focus on the design criteria. Results proved promising insights toward the development of gas sensors. The proposed structures have small dimensions as well as a wide functional interval.In Chapter 1,before employing the wavelength-division multiplexing (WDM) method, the notion of the electromagnetic wave in free space and in conductors with a description of equations was defined.Chapter 2 is dedicated to studying literature and similar research,started by the review of photonic crystals and photonic band gap. The gates, characteristics and design layouts were discussed without using nonlinear materials and optical amplifiers.Chapter 3 describes schemes proposed structures.In chapter 4, simulation studies and analysis of six new structures are presented. The procedure is as follows to use the linear logic NOT, OR and AND gates first. These structures have an input waveguide for applying a Gaussian optical pulse at a wavelength of 1550 nm. By changing the radius of the defect, the best dimension with the highest transmission is obtained.Afterward, by coupling these gates, and getting NOR and NAND gates in to study a reasonable contrast ratio and transmission power in each case by changing the defect radius obtained and proved the design concept. A full adder based on metal-insulator-metal (MIM) waveguide-based plasmonic waves. We studied the 4-input OR gate to design and simulate a full adder circuit, which used plasmonic waves to transmit signals; the 4-input gate presented in this study has a simple structure and is manufactured at a low cost. By optimizing the structure's dimensions, the losses and achieve a transmission coefficient of about 0.62 and educe the losses to 25% less than the mentioned design in the references.The next propose structure is a 2DPC based eight channels demultiplexer. This structure is proposed and designed using an octagonal ring resonator for WDM applications.The functional parameters are resonant wavelength, Q factor, channel spacing, spectral width, output efficiency, and crosstalk, are investigated. In this attempt, the channel selection is carried out by altering the octagonal ring resonator's size. The average transmission efficiency, Q factor, spectral width, and channel spacing of the proposed demultiplexer are 98.65%, 2212, 0.76 nm, and 1.75 nm, respectively. The proposed demultiplexer's crosstalk is low (30 dB ) as the even number of channels and the odd number of channels are dropped separately. The demultiplexer's size is about 752.64 µm2, and the functional characteristics of the proposed demultiplexer meet the requirements of WDM systems. Hence this demultiplexer can be incorporated for integrated optics. We have shown that the device is perfectly suitable for communication applications.Chapter 5 is the conclusion of the thesis and recommendation of future studies which has been presented for industrial purposes. In this thesis, a new photonic crystal slab for its use in gas sensing applications is proposed. Theoretical studies have been done to determine the response of the proposed structure to carbon dioxide. A simple laser with around 1 nm spectral widths can be used to simulate this device. Measurements can be done in two steps, which can be done simultaneously by using a reference device: step one with synthetic air and then adding known concentrations of CO.The output is referenced to the measurement with synthetic air.Our theoretical results show that variations of 17% in the transmission intensity and a clear variation on the transmission peaks' central wavelength.These results are already promising for the development of gas sensors
