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2021-06-01
Maswood, Mirza Mohd Shahriar, Uddin, Md Ashif, Dey, Uzzwal Kumar, Islam Mamun, Md Mainul, Akter, Moriom, Sonia, Shamima Sultana, Alharbi, Abdullah G..  2020.  A Novel Sensor Design to Sense Liquid Chemical Mixtures using Photonic Crystal Fiber to Achieve High Sensitivity and Low Confinement Losses. 2020 11th IEEE Annual Information Technology, Electronics and Mobile Communication Conference (IEMCON). :0686—0691.
Chemical sensing is an important issue in food, water, environment, biomedical, and pharmaceutical field. Conventional methods used in laboratory for sensing the chemical are costly, time consuming, and sometimes wastes significant amount of sample. Photonic Crystal Fiber (PCF) offers high compactness and design flexibility and it can be used as biosensor, chemical sensor, liquid sensor, temperature sensor, mechanical sensor, gas sensor, and so on. In this work, we designed PCF to sense different concentrations of different liquids by one PCF structure. We designed different structure for silica cladding hexagonal PCF to sense different concentrations of benzene-toluene and ethanol-water mixer. Core diameter, air hole diameter, and air hole diameter to lattice pitch ratio are varied to get the optimal result as well to explore the effect of core size, air hole size and the pitch on liquid chemical sensing. Performance of the chemical sensors was examined based on confinement loss and sensitivity. The performance of the sensor varied a lot and basically it depends not only on refractive index of the liquid but also on sensing wavelengths. Our designed sensor can provide comparatively high sensitivity and low confinement loss.
2017-03-08
Torabi, A., Shishegar, A. A..  2015.  Combination of characteristic Green's function technique and rational function fitting method for computation of modal reflectivity at the optical waveguide end-facet. 2015 International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS). 2:14–21.

A novel method for computation of modal reflectivity at optical waveguide end-facet is presented. The method is based on the characteristic Green's function (CGF) technique. Using separability assumption of the structure and rational function fitting method (RFFM), a closed-form field expression is derived for optical planar waveguide. The uniform derived expression consists of discrete and continuous spectrum contributions which denotes guided and radiation modes effects respectively. An optimization problem is then defined to calculate the exact reflection coefficients at the end-facet for all extracted poles obtained from rational function fitting step. The proposed CGF-RFFM-optimization offers superior exactness in comparison with the previous reported CGF-complex images (CI) technique due to contribution of all components of field in the optimization problem. The main advantage of the proposed method lies in its simple implementation as well as precision for any refractive index contrast. Excellent numerical agreements with rigorous methods are shown in several examples.