Indonesian Journal of Electrical Engineering and Computer Science Vol. 26, No. 3, June 2022, pp. 1477~1485 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v26.i3.pp1477-1485  1477 Journal homepage: http://ijeecs.iaescore.com Performance comparison of TOPAS chirped fiber Bragg grating sensor with Tanh and Gaussian apodization Dedi Irawan 1 , Khaikal Ramadhan 2 , Saktioto 2 , Azwir Marwin 2 1 Optoelectronics Laboratory Physics, Department of Physics Education, FMIPA, Universitas Riau, Pekanbaru, Riau, Indonesia 2 Plasma and Photonics Laboratory, Department of Physics, FMIPA, Universitas Riau, Pekanbaru, Riau, Indonesia Article Info ABSTRACT Article history: Received Jan 10, 2022 Revised Apr 19, 2022 Accepted Apr 21, 2022 In this work we carried out a numerical simulation with software Optigrating for Apodization chirped fiber Bragg grating (CFBG) with TOPAS material to improve sensitivity sensor, it was found that CFBG with a grating length of 50 mm has advantages in terms of ripple factor, side lobe left (SLL), and side lobe right (SLR) with values of -0,998 and -10,5264 dB, respectively. While the 10 mm CFBG has a narrower full-width half maximum (FWHM) with a value of 0.4528 nm. Tanh and Gaussian apodization were arranged in the CFBG design, it was found that the Tanh linear-CFBG had a narrow FWHM but for the ripple factor and the main lobe and side lobes were not good enough compared to the Tanh Cubicroot-CFBG, and the same pattern was also obtained in the Gaussian apodization. The narrow FWHM indicates the accuracy in detecting temperature, as well as the suppression of SLL and SLR. for the effect of apodization on CFBG it was found that The Tanh Linear-CFBG design with TOPAS material has the highest sensitivity which is -51.76 pm/oC compared to other designs. Keywords: Apodization Chirped fiber Bragg grating Gaussian Tanh Temperature Sensor TOPAS This is an open access article under the CC BY-SA license. Corresponding Author: Dedi Irawan Department Physics Education, PMIPA, Universitas Riau Pekanbaru, Riau, Indonesia Email: dedi.irawan@lecturer.unri.ac.id 1. INTRODUCTION Fiber Bragg grating (FBG) which has a grating with a periodically changing refractive index has received great attention in recent years, FBG can be used as optical filters, dispersion compensation in optical communications, and optical sensors [1]. The behavior of the Bragg grating which can filter the input signal makes it a widely preferred and researched wavelength-based sensor. Factors such as not being susceptible to electromagnetic waves, small size, fast and safe response, and biocompatibility make FBG attractive to researchers. This has happened since the demonstration of photon-induced refractive index modulation in the last three decades. FBG sensor grating has different shapes and is used in various fields such as the oil and gas industry [2], aviation [3], medical [4], strain sensing [5], and temperature [6], [7], and monitoring in nuclear plants [8]. In general, FBG is sensitive to changes in physical parameters such as strain and temperature independently, which we cannot separate the effects of the two quantities normally, but requires special measures, as well as simultaneous temperature and strain sensing. Physical information such as temperature and strain is encoded in terms of wavelengths. The wavelength of transmission and reflection of the reflected signal through the grating provides inseparable information on the influence of temperature and the effect of the strain. In separating the effects of the two solutions, the second FBG isolated from the strain is used as a reference in temperature measurements while a single FBG is left to measure the temperature and strain quantities [9], [10].