scholarly journals Arc-Induced Long Period Fiber Gratings

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Gaspar Rego

Long period fiber gratings produced by the electric arc technique have found an increasing interest by the scientific community due to their ease to fabricate, virtually enabling the inscription in any kind of fiber, low cost, and flexibility. In 2005 we have presented the first review on this subject. Since then, important achievements have been reached such as the identification of the mechanisms responsible for gratings formation, the type of symmetry, the conditions to increase fabrication reproducibility, and their inscription in the turning points with grating periods below 200 μm. Several interesting applications in the sensing area, including those sensors working in reflection, have been demonstrated and others are expected, namely, related to the monitoring of extreme temperatures, cryogenic and high temperatures, and high sensitivity refractometric sensors resulting from combining arc-induced gratings in the turning points and the deposition of thin films in the transition region. Therefore, due to its pertinence, in this paper we review the main achievements obtained concerning arc-induced long period fiber gratings, with special focus on the past ten years.

2017 ◽  
Vol 54 (10) ◽  
pp. 100602
Author(s):  
邓 靖 Deng Jing ◽  
冯元华 Feng Yuanhua ◽  
高社成 Gao Shecheng ◽  
李朝晖 Li zhaohui

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1500 ◽  
Author(s):  
P.S.S. dos Santos ◽  
P.A.S. Jorge ◽  
José de Almeida ◽  
L. Coelho

We present a portable and low-cost system for interrogation of long-period fiber gratings (LPFGs) costing around a 30th of the price of a typical setup using an optical spectrum analyzer and a broadband light source. The unit is capable of performing real-time monitoring or as a stand-alone data-logger. The proposed technique uses three thermally modulated fiber-coupled laser diodes, sweeping a few nanometers around their central wavelength. The light signal is then modulated by the LPFG and its intensity is acquired by a single photo-detector. Through curve-fitting algorithms the sensor transmission spectrum is reconstructed. Testing and validation were accomplished by inducing variations in the spectral features of an LPFG through changes either in external air temperature from 22 to 425 °C or in refractive index (RI) of the surrounding medium from 1.3000 to 1.4240. A dynamic resolution between 3.5 and 1.9 °C was achieved, in temperatures from 125 to 325 °C. In RI measurements, maximum wavelength and optical power deviations of 2.75 nm and 2.86 dB, respectively, were obtained in the range from 1530 to 1570 nm. The worse RI resolution obtained was 3.47 × 10 − 3 . The interrogation platform was then applied in the detection of iron corrosion, expressing wavelength peak values within 1.12 nm from the real value in the region between 1530 and 1570 nm.


2007 ◽  
Author(s):  
I. Cacciari ◽  
M. Brenci ◽  
R. Falciai ◽  
G. Nunzi Conti ◽  
S. Pelli ◽  
...  

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