CHITTAGONG INDEPENDENT UNIVERSITY (CIU)

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CIU Journal ISSN (Print): 2664-0457 ISSN (Online): 2664-0465 CIU Journal (Chittagong Independent University Journal), a double blind peer-reviewed journal, is published in hard and soft forms in December every year. However, a submission is welcomed any time of the year. CIU journal promises to an esteemed outlet for showcasing high-quality research related to all branches of contemporary knowledge – natural sciences, social sciences, liberal arts, engineering, business and law. The CIU journal is destined to advance the contemporary theoretical and empirical knowledge through publication and dissemination of innovative research articles to the scholarly community with special emphasis on Bangladesh and other emerging economies of the world. Thus, the CIU Journal is multidisciplinary in scope and is open to all research methods including qualitative, quantitative and mixed approaches. The CIU Journal publishes empirical papers, conceptual papers, review papers, case studies, research notes, practitioners’ perspectives and book reviews.

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    Design and Analysis of Optical Planar Waveguide by Tapering Approach for Mid-infrared Supercontinuum Generation
    (CIU Journal, 2020-12-01) M R Karim1, Nayem Al Kayed2, Md. Rabiul Hossain3, Golap Kanti Dey4
    Varying dispersion and nonlinearity by tapering the thickness of a planar waveguide along the pulse propagation direction instead of keeping it uniform, create an opportunity to extend the supercontinuum spectral coverage further into the mid-infrared region. In this work, we numerically proposed a 5-mm-long group-velocity dispersion tailored silicon-rich nitride tapered waveguide for wideband supercontinuum coverage in the mid-infrared. Applying 50 fs FWHM sech pulses at the center of 1.55 µm wavelength with a relatively low input power of 50 W, it was possible to achieve supercontinuum coverage from 0.8 µm to 9 µm by our proposed design. Besides, the results obtained using our proposed waveguide show that tapering the geometry enhances the supercontinuum coverage approximately 90% compared to a uniform waveguide of the same length. To the best of our knowledge, this would be the widest spectrum demonstrated ever using the tapered waveguide structure proposed so far. It may enable some spectacular mid-infrared region applications such as spectroscopic measurement, biomedical imaging, optical coherence tomography as well as sensing applications, etc.
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    Evaluation of Deep Neural Networks for Predicting Optical Properties of Silicon-rich Silicon Nitride Waveguide
    (CIU Journal, 2021-12-01) M R Karim1, Abrar Hussain2, Al Kayed3, B M A Rahman4
    Deep learning (DL) has recently emerged as a potential platform for estimating linear and nonlinear optical phenomena of waveguides due to its high computational power, high-level structures and flexible usages. In this work, we performed a comparative analysis of four DL based Deep Neural Network (DNN) configurations for predicting and analyzing the effective mode area of a planar Silicon-rich Silicon Nitride (SRN) waveguide, its nonlinear coefficient, effective index and dispersion in the wavelength range of 0.65 µm – 3.05 µm, waveguide core width of 1 µm – 5 µm and waveguide height of 0.3 µm –0.4 µm. We found that out of four DNN structures analyzed, ELU-ELU-ReLU-70-9000 structure showed superior performance in terms of mean squared error values. The computational time required with deep neural network (for training) and finite-element method (FEM) solutions is also compared and found that the training time of DNN structures increased with a number of epochs and due to the ReLU activation function. This simple and fast-training DNN employed here predict the output for unfamiliar parameter setting of the optical waveguide faster than traditional numerical simulation techniques.
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