Faculty Publications
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Item Highly birefringent photonic crystal fiber with hybrid cladding(Academic Press Inc. apjcs@harcourt.com, 2019) Krishnan, K.; Malavika, R.A highly birefringent hybrid cladding photonic crystal fiber (PCF) is proposed in this article. The guiding properties of the proposed PCF are numerically investigated using the finite element method (FEM). This fiber exhibits very high birefringence in the order of10-2 at communication wavelengths. In addition, low confinement loss of 6.1 × 10?3 dB/km, lower negative dispersion of -274.5ps/nm/km and higher nonlinearity of 76.41W-1km-1 is achieved at the same wavelengths compared with the exist literature. The proposed simple cladding structure is easy for fabrication. Moreover, effective mode area and nonlinear coefficient are analyzed and optimized. The proposed fiber can prove its applications in sensing, telecommunication and non-linear technologies. © 2018 Elsevier Inc.Item Design optimization of a highly sensitive spiral photonic crystal fiber for liquid and chemical sensing applications(Academic Press Inc. apjcs@harcourt.com, 2019) Malavika, R.; Krishnan, P.In this paper, a spiral shaped photonic crystal fiber (PCF)is proposed for liquid sensing applications. The guiding properties of the proposed PCF are analysed. Sensitivity coefficient is analysed by varying different structural parameters for a wider wavelength range. In addition, confinement loss is also studied at the same wavelengths. The relative sensitivity achieved for the optimized parameters are 56.8%, 58.3% and 62.7% for water (n = 1.33), propane (n = 1.34)and propylene (n = 1.36)respectively. With its low confinement loss and high sensitivity the proposed PCF can be used for liquid and chemical sensing applications. © 2019 Elsevier Inc.Item Hollow-core high-sensitive photonic crystal fiber for liquid-/gas-sensing applications(Springer Science and Business Media Deutschland GmbH, 2021) Revathi, R.; Anand, U.; Krishnan, P.A low confinement loss of hollow-core photonic crystal Fiber (HC-PCF) for liquid-/gas-sensing applications has been proposed. Various HC-PCF backgrounds such as silica, BK7 and Teflon glass with different core materials such as glycerol, benzene and toluene have been studied using a finite element method with perfectly matched layer-based COMSOL software. The performance of the proposed PCF is analyzed using different metrics such as confinement loss, effective area, numerical aperture, relative sensitivity and effective refractive index for different combinations to compare the effects of different backgrounds in HC-PCF. The proposed HC-PCF structure offers relative sensitivity of 91.96% and 1.74 × 10?14 dB/m of confinement loss using Teflon glass as the substrate for benzene. The proposed PCF can be used for liquid- and gas-sensing applications with its low confinement loss and high sensitivity. The proposed simple cladding structure is easy to fabricate and offers 26% improved relative sensitivity compared to existing PCFs in the literature. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.Item Photonic crystal fiber sensor for the detection of hazardous gases(Springer Science and Business Media Deutschland GmbH, 2022) Nizar, S.M.; Elizabeth Caroline, E.C.; Krishnan, P.Three different Photonic Crystal Fiber (PCF) gas sensors are designed to detect five different gases for a wide range of wavelengths. The three unique configurations are designed based on four outer Elliptical cores PCF (4E-PCF), four outer Circular cores (4C-PCF) PCF, and different Eight Elliptical cores PCF (8E-PCF) to analyze and sense the light interface with applied gases. For three proposed gas sensors, the sensing parameters for five different hazardous gases, such as relative sensitivity, effective area, birefringence and dispersion, are acquired. The five different gases considered in the sensor investigation are Sulfur trioxide [SO3] (20 °C), Tetracholorosilane [SiCl4], Tetracholoromethane [CCl4], Turpentine [C10H16], Tin Terra chloride [SnCl4]. Among the three designs, 8E-PCF yields a maximum sensitivity of 75.75%, an effective area of 2.45μm2, and a birefringence of 0.0421 for SnCl4 gas. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item A Highly Sensitive Photonic Crystal Fiber Gas Sensor for the Detection of Sulfur Dioxide(Springer Science and Business Media B.V., 2022) Elizabeth Caroline, E.C.; Nizar, S.M.; Krishnan, P.Sulfur dioxide (SO2) is one of the most prevalent contaminants in the atmosphere. It is mostly generated as a byproduct of the burning of sulfur-containing coal and oils, as well as the smelting of various ores. SO2 contributes to the development of major diseases such as asthma and chronic bronchitis. In this paper, we proposed a Wheel Structured circular air hole Photonic Crystal Fiber (WS-PCF) based gas sensor to detect SO2 gas. The proposed WS-PCF gas sensor consists of a four-layer-thick circular cladding air hole. The diameter of the first layer varies throughout the optimization procedure, while the diameters of the succeeding three layers remain constant. The numerical investigation on the sensor parameters such as numerical aperture, effective area, non-linearity, confinement, loss and the relative sensitivity of the proposed sensor are extensively analyzed in a wavelength range of 0.9 µm to 1.2 µm. The proposed WS-PCF gas sensor offers the highest relative sensitivity of 83.64% and a lower confinement loss of 6.34 × 10 - 9dB/ km. The proposed sensor is simple and offers 14% high sensitivity and very low confinement loss (10-3reportedinliterature) compared with the exist literature. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.