Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm

Abstract

This paper presents the achievements and progress made on the polymer optical fiber (POF) gratings inscription in different types of Fiber Bragg Gratings (FBGs) and long period gratings (LPGs). Since the first demonstration of POFBGs in 1999, significant progress has been made where the inscription times that were higher than 1 h have been reduced to 15 ns with the application of the krypton fluoride (KrF) pulsed laser operating at 248 nm and thermal treatments such as the pre-annealing of fibers. In addition, the application of dopants such as benzyl dimethyl ketal (BDK) has provided a significant decrease of the fiber inscription time. Furthermore, such improvements lead to the possibility of inscribing POF gratings in 850 nm and 600 nm, instead of only the 1550 nm region. The progress on the inscription of different types of polymer optical fiber Bragg gratings (POFBGs) such as chirped POFBGs and phase-shifted POFBGs are also reported in this review.

Review of Chirped Fiber Bragg Grating (CFBG) Fiber-Optic Sensors and Their Applications

“…The main rationale for using polymer optical fibers (POFs) based on polymethyl methacrylate (PMMA) compound, in lieu of standard glass fibers for the inscription of CFBG sensors, is the change of thermal sensitivity [ 70 ]. While glass fibers achieve typical thermal sensitivity values of 10–15 pm/°C and strain sensitivity around 1 pm/με at 1550 nm, POF fibers have a larger thermal response, usually having negative sign (i.e., the larger the temperature, the smaller the Bragg wavelength).…”

“…Among the several setups designed for POF FBGs, the KrF-based setup described by Marques et al [ 70 ] allows a high efficiency and a short inscription time; the setup is sketched in Figure 6 (image from [ 70 ]). The laser is a KrF excimer laser at 248 nm emission wavelength, with 15 ns pulse duration.…”

“… Schematic of phase mask inscription setup based on KrF pulsed laser for inscription of gratings on PMMA fibers, reported by Marques et al; image from [ 70 ]. …”

Optimizing Linearity and Sensitivity of 3D-Printed Diaphragms With Chirped FBGs in CYTOP Fibers

“…FBGs are created through a refractive index modulation when the fiber is exposed to a periodic intensity pattern [13]. If the period is constant, a uniform FBG is created, whereas a non-constant period is used, it results in a non-uniform FBG, which can be classified as phase-shift or chirped FBG depending on the period variation [15]. Chirped FBGs are created through a linear variation of the period on the refractive index modulation [16].…”

Latest Achievements in Polymer Optical Fiber Gratings: Fabrication and Applications

“…Previous literature includes extensive reviews published by Webb [1], Luo et al [66], Canning [68], Marques et al [69,70], Broadway et al [71], Berghmans et al [72], and Nogueira et al [73], focusing on the uniform POF gratings fabrication and applications. Due to the emerging POF applications in communications and sensing, intense work has been done in recent years towards obtaining a short, flexible, and reliable fabrication process for gratings in these fibers.…”