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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/13631
Title: Design optimization of two concatenated long period waveguide grating devices for an application specific target spectrum
Authors: Semwal G.
Rastogi, Vipul K.
Published in: Applied Optics
Abstract: We propose a global optimization method to optimize the parameters of two concatenated long period waveguide gratings (LPWGs) for generating a desired target spectrum. The design consists of two concatenated LPWGs with different grating periods inscribed in the guiding films of a four-layer planar waveguide with finite over cladding. We have used the transfer matrix method to compute the modes of the structure and the coupled mode theory to compute the spectrumof the device. The adaptive particle swarm optimization method has been used to optimize the parameters of LPWGs to generate symmetric as well as asymmetric target spectra. Two concatenated gratings of different lengths and periods have been used to generate the target spectra. To demonstrate the method of optimization we have designed a variety of wavelength filters including a rectangular shape rejection band filter, asymmetric band rejection filters, band rejection filters for flattening the amplified spontaneous emission (ASE) spectrum of an erbium doped fiber amplifier (EDFA), and a gain equalization filter for an erbium doped waveguide amplifier (EDWA) in the C-band. Seven parameters of the proposed LPWG structure have been optimized to achieve the desired spectra. We have obtained an ASE flattening with ±0.8 dB peakto-peak ripple in case of the EDFA and gain flattening with ±0.4 dB peak-to-peak ripple in case of an EDWA. The study would be useful in the design of wavelength filters for specific applications. © 2015 Optical Society of America.
Citation: Applied Optics (2015), 54(12): 3141-3149
URI: https://doi.org/10.1364/AO.54.003141
http://repository.iitr.ac.in/handle/123456789/13631
Issue Date: 2015
Publisher: OSA - The Optical Society
ISSN: 1559128X
Author Scopus IDs: 50761464800
7006364661
Author Affiliations: Semwal, G., Instrument Research and Development Establishment, Dehradun, 248008, India
Rastogi, V., Department of Physics, Indian Institute of Technology Roorkee, Roorkee, 247667, India
Corresponding Author: Semwal, G.; Instrument Research and Development EstablishmentIndia; email: girishsemwal@rediffmail.com
Appears in Collections:Journal Publications [PH]

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