Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

Terahertz Sensor via Ultralow-Loss Dispersion-Flattened Polymer Optical Fiber: Design and Analysis

A novel cyclic olefin copolymer (COC)-based polymer optical fiber (POF) with a rectangular porous core is designed for terahertz (THz) sensing by the finite element method. The numerical simulations showed an ultrahigh relative sensitivity of 89.73% of the x-polarization mode at a frequency of 1.2 THz and under optimum design conditions. In addition to this, they showed an ultralow confinement loss of 2.18 × 10−12 cm−1, a high birefringence of 1.91 × 10−3, a numerical aperture of 0.33, and an effective mode area of 1.65 × 105 μm2 was obtained for optimum design conditions. Moreover, the range dispersion variation was within 0.7 ± 0.41 ps/THz/cm, with the frequency range of 1.0–1.4 THz. Compared with the traditional sensor, the late-model sensor will have application value in THz sensing and communication

A highly sensitive quadruple D-shaped open channel photonic crystal fiber plasmonic sensor : A comparative study on materials effect

Funding Information: This work was supported by the National Research Foundation of Korea-Grant funded by the Korean Government (Ministry of Science and ICT-NRF-2020R1A2B5B02002478). Publisher Copyright: © 2021 The Author(s)Peer reviewedPublisher PD

Dual-Core Transversally Chirped Microstructured Optical Fiber for Mode-Converter Device and Sensing Application

We propose and demonstrate the concept of transversally chirped microstructured optical fiber and its application for the development of new platforms for sensing and telecommunications devices. First, the feasibility of the structure is demonstrated through two different techniques of manufacture. Based on the proposed structure, a novel mode-converter device is numerically studied. It is found that the mode conversion between LP01 and LP11 modes can be continuously tuned by temperature changes from 25 to 75°C. And that, the coupling efficiency in the wavelength range between 1.2 μm and 1.7 μm is always higher than 65%. Consequently, the proposed mode converter can operate in the E + S + C + L + U bands. Finally, a similar structure was used to design a new sensing architecture, which consisting of a dual-core transversally chirped microstructured optical fiber for refractive index sensing of fluids. We show that by introducing a chirp in the hole size, the microstructured optical fiber can be a structure with decoupled cores, forming a Mach–Zehnder interferometer in which the analyte directly modulates the device transmittance by its differential influence on the effective refractive index of each core mode. We show that by filling all fiber holes with analyte, the sensing structure achieves high sensitivity (transmittance changes of 302.8 per RIU at 1.42) and has the potential for use over a wide range of analyte refractive index

Milled Microchannel-Assisted Open D-Channel Photonic Crystal Fiber Plasmonic Biosensor

Funding Information: This work was supported by the National Research Foundation of Korea-Grant funded by the Korean Government (Ministry of Science) under Grant ICT-NRF-2020R1A2B5B02002478.Peer reviewedPublisher PD

Highly sensitive photonic crystal fiber salinity sensor based on Sagnac interferometer

For a sensor, high sensitivity, structural simplicity, and longevity are highly desired for measurement of salinity in seawater. This work proposed an ultrahigh sensitive photonic crystal fiber (PCF) salinity sensor based on the sagnac interferometer (SI). The propagation characteristics of the proposed PCF are analyzed by the finite element method (FEM). The achieved sensitivity reaches up to 37,500 nm/RIU and 7.5 nm/% in the salinity range from 0% to 100%. The maximum resolutions of 2.66 × 10−06 RIU and 1.33 × 10−02% are achieved with high linearity of 0.9924 for 2.20 cm length of the proposed PCF. Owing to such excellent results, this proposed sensor offers the potential to measure the salinity of seawater

Fabrication and Sensing Applications of Special Microstructured Optical Fibers

This chapter presents the fabrication of the special microstructured optical fibers (MOFs) and the development of sensing applications based on the fabricated fibers. Particularly, several types of MOFs including birefringent and photosensitive fibers will be introduced. To fabricate the special MOFs, the stack-and-draw technique is employed to introduce asymmetrical stress distribution in the fibers. The microstructure of MOFs includes conventional hexagonal assembles, large-air hole structures, as well as suspended microfibers. The birefringence of MOFs can reach up to 10−2 by designing the air hole structure properly. Fiber Bragg gratings as well as Sagnac interferometers are developed based on the fabricated special MOFs to conduct sensing measurement. Various sensing applications based on MOFs are introduced

Asymmetrical D-channel photonic crystal fiber-based plasmonic sensor using the wavelength interrogation and lower birefringence peak method

Funding Information: This work was supported in part by Independent University, Bangladesh ( IUB ), and in part by Sejong university through its faculty research program ( 20192021 ). This paper was also supported by research funds of Jeonbuk National University in 2020.Peer reviewedPublisher PD