The discovery of the fiber Bragg grating (FBG) is an early milestone in developing optical fiber technology, such as optical communication to monitoring material health structures as sensors. For optical communication, the FBG components are capable of filtering functions. As a sensor, it has a high sensitivity immune to electromagnetic wave interference, is small in size, and is resistant to extreme environmental conditions. The sensitivity of the FBG sensor is obtained from the shift in the peak wavelength of each of the temperature and strain quantities. However, the performance of the FBG sensor can be improved by engineering the distribution of the refractive index on the grid with the apodization and chirp functions. Apodization is a technique to improve the performance of the FBG to eliminate noise, narrow the full width half maximum, lower the side lobes of the main lobe, and improve the spectrum ripple factor. Apart from apodization, the chirp function also affects the sensor sensitivity and the refractive index distribution on the grid. Numerical experiments were carried out in designing the FBG component as a sensor using Gaussian apodization and Topas (cyclic olefin copolymer) for several chirp functions. The results show that the Gaussian apodization Topas for all chirp functions as a strain sensor has the same sensitivity, namely 0.84 pm/μstrain while for temperature sensors with the highest sensitivity is obtained at cubic root chirp of 13.82857 pm/°C followed by square root chirp of 13.74286 pm/°C, quadratic chirp 13.71429 pm/°C, and linear chirp 13.4 pm/°C. The Bragg wavelength shift was greater for 1 °C than for the 1 μstrain.

Optical sensors have more capabilities than electronic sensors, and therefore provide extraordinary developments, including high sensitivity, nonsusceptibility to electromagnetic wave disturbances, small size, and multiplexing. Furthermore, fiber Bragg grating (FBG) is an optical sensor with a periodically changing grating refractive index, susceptible to strain and temperature changes. As a sensor, FBG's performance required to optimize and improve the numerical apodization function and affect the effective refractive index is considered. The grating fiber's apodization function can narrow the full width half maximum (FWHM) and reduce the optical signal's side lobes. In all the apodization functions operated by FBG, Blackman has the highest sensitivity of 15.37143 pm/°C, followed by Hamming and Gaussian, with 13.71429 pm/°C and 13.70857 pm/°C, respectively, and Uniform grating fiber with the lowest sensitivity of 12.40571 pm/°C. Hamming, Uniform, and Blackman discovered the sensitivity for a strain to be 1.17, 1.16, and 1.167 pm/microstrain, respectively. The results obtained indicated that apodization could increase FBG's sensitivity to temperature and strain sensors. For instance, in terms of other parameters, FWHM width, Hamming had the narrowest value of 0.6 nm, followed by Blackman with 0.612 nm, while Uniform had the widest FWHM of 1.9546 nm.

This paper reports the implementation of the STEM learning strategy to the 20 physics students on optical physics concepts. Previously, student understanding on this subject was categorized as weak, this was caused by not only learning just carried out theoretically but also the student's limitation to figure out the optical phenomenon. This research is to identify the student learning outcomes before and after STEM implementation by using simple experimental work with a set of pre-test and post-test. The calculation results show that the student's outcome has a medium enhancement which is about 0.53. Certainly, a Stem learning strategy is a good choice as a teaching strategy in the Optical Physics subject.

The effect of dispersion will interfere with the signal transmission. Several ways can be done in compensating the dispersion such as by utilizing dispersion compensator fiber (DCF) or chirp fiber Bragg grating (CFBG). The dispersion compensation schemes with DCF are expensive and it also causes nonlinear optical effects, meanwhile, the CFBG can reduce costs and promise better results. In this study, an Apodization Chirped Fiber Bragg Grating (ACFBG) has been developed as a dispersion compensator with Optisystem with non-return to zero (NRZ) 20 Gbps. It is found that the Gaussian Cubic-CFBG apodization with a size of 90 mm had the highest Q-factor evaluation of  20,776 dB for a 250 km dispersion compensation scheme. this result is much larger than the previous CFBG dispersion compensation scheme. This study also confirmed that the Gaussian Apodization was the best profile compared to Tanh Apodization, from the evaluation of the Q-factor, Tanh cubic-CFBG only obtained a Q-factor of 9.6 dB. Certainly, the high performance of ACFBG as a dispersion compensator is very useful to support optical communication systems

<span>In this paper, we investigate a hexagonal two-layer photonic crystal fiber based on surface plasmon resonance (HT-PCF-SPR) which is easy to fabricate as a sensor for detecting the refractive index of analytes. After performing numerical simulations using COMSOL multiphysics based on the finite element method (FEM), it was found that the HT-PCF-SPR could detect the analyte's refractive index in the range 1.34-1.37 RIU and in the wavelength range from 730 nm to 810 nm. The plasmonic material used in the design is gold with a thickness of 40 nm which is located outside the layer and in two opposite air holes in the core. The HT-PCF-SPR design has good performance in detecting analytes, it is found that the sensitivity in detecting analytes is 2,000 nm/RIU, meaning that every 1 RIU shift of analyte shifts the wavelength by 2000 nm. Meanwhile, the sensor resolution obtained from the design is 6.67×10-5 RIU, and it is found that the larger the air hole, the greater the confinement loss value.</span>

In this work, we carried out a numerical investigation of the PCF-SPR biosensor for the early detection of infected skin cancer cells and healthy cells. The study was conducted using the COMSOL Multiphysics-based FEM method. The dielectric material used in this PCF design is fused silica, while the plasmonic material is gold. The study was conducted to test the effect of the thickness of the plasmonic layer and the size of the air hole diameter on the PCF-SPR. It was found that the larger the diameter of the air hole in the proposed sensor gives a smaller confinement loss value, while the thicker the plasmonic material used also gives a small confinement loss value. The proposed PCF-SPR has a wavelength sensitivity in detecting skin cancer-infected cells of 7000 nm/RIU. These results indicate that the proposed sensor has a good performance in detecting cells infected with skin cancer.

The discovery of the fiber Bragg grating (FBG) is an early milestone in the development of optical fiber technology, such as in optical communication to monitoring of material health structures as sensors. For optical communication the FBG components are capable of filtering certain signals.In the FBG optical sensor has a high sensitivity immune to electromagnetic wave interference, small size and is resistant to extreme environmental conditions. The sensitivity of the FBG sensor is obtained from the shift in the peak wavelength of each of the temperature and strain quantities. However, the performance of the FBG sensor can be improved by engineering the distribution of the refractive index on the grid with the apodization and chirp functions. Apodization is a technique to improve the performance of the FBG sensor by eliminating noise, narrowing the full wave half maximum, lowering the side lobes of the main lobe and improving the spectrum ripple factor. Apart from apodization, the chirp function also affects the sensor sensitivity and the distribution of the refractive index on the grid. Numerical experiments were carried out in designing the FBG component as a sensor using Gaussian apodization and Topaz cyclic olefin copolymer for several chirp functions. The results show that Gaussian apodized topass lattice fibers for all chirp functions as a strain sensor have the same sensitivity, namely 0.84 pm/μstrain while for temperature sensors the highest sensitivity is obtained at cubic root chirp 13.82857 pm/°C followed by square chirp 13.74286 pm/°C, Quadratic chirp 13.71429 pm/°C and Linear Chirp 13.4 pm/°C the Bragg wavelength shift was greater for 1 °C than for the 1 μstrain.

The purpose of this study was to analyze the social competence of science teachers. It was conducted in 22 SMP Negeri Dumai City with a population of 86 science teachers in public junior high schools. The research sample was 71 science teachers calculated using the Slovin formula at an error rate of 0.05%. The instrument used in data collection was a questionnaire that was pre-tested to 30 science teachers (15 science teachers at SMPN Dumai City and 15 science teachers at SMPN Duri). From the 30 items of the questionnaire statement that were tested, the validity of each item was calculated with the product moment correlation with the help of the SPSS version 23, 29 valid items were obtained. Calculation of instrument reliability using the Cronbach Alpha formula was obtained 0.931 very reliable category. Furthermore, the social competence questionnaire instrument for science teachers who had met the validity and reliability requirements was used to collect data for the research sample of 71 science teachers at public junior high schools in the city of Dumai. The results of descriptive data analysis showed that the social competence of science teachers at the Dumai City Junior High School was 54.90% (39 science teachers) in the medium category, 25.30% (18 science teachers) who had high category competence and 19.70% (14 science teachers) out of 71 science teachers in the low category. Thus, the social competence of science teachers in Dumai City Junior High School is mostly in the medium category.