Femtosecond laser fabrication of long period fiber gratings by a transversal-scanning inscription method and the research of its orientational bending characteristics

A high-sensitivity curvature sensor with dual-parameter measurement ability based on angularly cascaded long-period fiber grating (AC-LPFG) is proposed and experimentally demonstrated, which consists of two titled LPFGs (TLPFGs) with different tilt angles and the same grating period. AC-LPFG was fabricated by using a deep ultraviolet laser and an amplitude-mask in our laboratory. The experimental results show that simultaneous measurement of curvature and temperature can be achieved by monitoring the wavelengths of two resonant peaks for different TLPFGs. The two peaks show opposite shifts with increasing curvature and has a maximum curvature sensitivity of 16.392 nm/m−1. With the advantages of low cost, high sensitivity, and dual-parameter measurements, our sensor has more potential for engineering applications.

Section: Introductionmentioning

confidence: 99%

Angularly Cascaded Long-Period Fiber Grating for Curvature and Temperature Detection

Xiao,

Du,

Ling

et al. 2023

“…Since the end of the 90s, to date, many techniques have been reported in the LPFGs inscription, such as UV, CO 2 , femtosecond irradiation, electric arc, and mechanically-induced between other methods [ 1 , 5 , 6 , 7 , 8 ]. Today, most of these techniques have been improved to achieve LPFGs with specific physical properties for different applications [ 9 , 10 , 11 , 12 ]. Recently, other methods have been proposed using the attractive LPFGs inscription process [ 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanically-Induced Long-Period Fiber Gratings Using Laminated Plates

Torres-Gómez

Ceballos-Herrera

Salas-Alcántara

2020

This work presents a formation method of mechanically-induced long-period fiber gratings using laminated plates. The mechanically-induced long-period fiber grating is temporarily inscribed by compressing the optical fiber between a flat plate and the proposed laminated plate. In turn, the new laminated plate consists of a parallel assembling of single-edged utility blades. We present the experimental characterization of mechanically-induced long-period fiber gratings while employing three laminated plates with a period of 480 ± 20 µm and low duty cycles. These mechanically-induced long-period fiber gratings display a leading rejection band (>15 dB) with a couple of shallow rejection bands (<2 dB) in the range of 1100–1700 nm. This spectral behavior is due to the new mechanical fabrication process that is based on laminated plates that we have proposed, which consists of piling multiple blades with trapezoidal edges that are polished with different levels to obtain different duty-cycles. With the proposed method, we can obtain values of duty-cycles around 10%, much lower than those obtained using traditional methods. Additionally, with this new method, the required mechanical pressure to form the grating is remarkably reduced, which minimizes the probability of the optical fiber failure in the mechanically-induced long-period fiber gratings (MI-LPFGs). Moreover, the proposed mechanically-induced long-period fiber gratings with a single rejection band open the feasibility to implement coarse wavelength division multiplexing systems that are based on long-period fiber gratings.

“…In 2010, Liu et al presented a new method for fabricating LPFGs by periodically drilling holes into the photonic crystal fiber cladding using a focused infrared Fs laser [ 15 ]. Recently, Dong et al proposed a transversal-scanning inscription method to fabricate LPFGs using an 800 nm infrared Fs laser [ 17 ]. It was determined that LPFGs fabricated with this method exhibit opposite bending characteristics compared with LPFGs inscribed with the point-by-point method.…”

Section: Introductionmentioning

confidence: 99%

Sensing Characteristics of Tilted Long Period Fiber Gratings Inscribed by Infrared Femtosecond Laser

Tang

Bai

et al. 2018

We propose a novel tilted long period fiber grating (TLPFG) design, inscribed using a line-by-line inscription technique and an infrared femtosecond (Fs) laser. The responses of this TLPFG to external refractive index, temperature, torsion, and strain were systematically investigated to determine its sensing characteristics. The external refractive index (RI) was measured to be −602.86 nm/RIU at an RI of ~1.432. The TLPFG was used to accurately measure temperatures up to 450 °C with a sensitivity of 103.8 pm/°C. The torsion and strain sensitivity of the device were 48.94 nm/(rad/mm) and −0.63 pm/µε, respectively. These results demonstrate that the proposed TLPFG could be used as sensors in a series of application fields including high temperatures and external environments.