Design and Manufacturing Optoelectronic Sensors for the Measurement of Refractive Index Changes under Unknown Polarization State

Abstract

This article proposes a new method for detecting slight refractive index changes under conditions of unknown polarization state. It is argued that an insignificant modification of the tilted fiber Bragg grating (TFBG) structure and selecting the appropriate spectral region allows us to accurately track changes in the refractive index. It has also been proven that the method can be easily made insensitive to temperature and that the sensitivity to changes in the polarization plane of the input light can be significantly reduced, which is crucial in later practical applications. Analytes in the form of an aqueous glucose solution were used to calibrate the sensor. The proposed method, based on perpendicular tilted fiber Bragg grating (P-TFBG), has a wide range of universality because its development and slight modification will enable the detection of glucose, pathogens, and viruses.

Highly Sensitive On-Chip Grating-Based Optical Sensor on Glass Substrate: Cost-Effective Design

“…This finding underscores the capability of the Bragg grating sensor to deliver temperature-independent RI measurements, thereby fortifying its reliability and accuracy in diverse operating conditions [3,15]. The sensor system and measuring method exhibit inherent capabilities for concurrent measurement of both temperature and refractive index, or for conducting refractometric measurements that demonstrate remarkable insensitivity to variations in temperature [16]. biocompatibility, streamlined fabrication procedures, and adjustable optical, thermal, and mechanical properties.…”

Identification of cladding modes in SMF-28 fibers with TFBG structures

“…The information above enables determination of the modes of the measured TFBG characteristics in the Bragg and ghost mode areas, 𝑖.𝑒., those constituting the spectral ranges corresponding to the Bragg mode and ghost mode minima. Figure 3 shows the spectral characteristics of the TFBG structure in the analyzed spectral range, measured at a temperature of 20 • C, in the free state and the bent state, with the input light polarization consistent with the P state [11]. The two spectral regions not yet discussed include the high-order cladding mode and loworder cladding mode areas.…”

“…Consequently, they can be used in 𝑒.𝑔., explosive hazardous environments to detect many physical quantities and physical decomposition [7]. Their 3D modifications in the form of tilted fiber Bragg grating (TFBG) structures significantly expand the spectrum of their applications [8] and open up a range of possibilities for new measurements, 𝑒.𝑔., measurement of the concentration of various substances in aqueous solutions [9], refractometry [10], measurement of the light polarization plane [11,12] and many others.…”

“…1. The grating has a diffraction plane tilt angle equal to 2 • , and the input light is polarized according to the P state [11]. The entire structure has a length of 15 mm.…”

Physical foundations determining spectral characteristics measured in Bragg gratings subjected to bending

“…Optical methods of measuring physical quantities have been widely researched and developed [3]. Ordinary fiber Bragg gratings (FBG) and their numerous variations, 𝑒.𝑔., in the form of oblique structures, are increasingly used as converters of mechanical quantities into optical parameters [4][5][6]. The use of these elements as bending sensors requires, for example, their placement in photonic fibers with photonic gap PBGFs (all-solid photonic bandgap fibers) [7].…”