scholarly journals Effect of Low-Doses of Gamma Radiation on Electric Arc-Induced Long Period Fiber Gratings

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2318
Author(s):  
Patricia Mesonero-Santos ◽  
Ana Fernández-Medina ◽  
Luis C. C. Coelho ◽  
Duarte Viveiros ◽  
Pedro A. Jorge ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Arc Discharge ◽  
Single Mode ◽  
Electric Arc ◽  
Good Choice ◽  
Wavelength Shift ◽  
Fiber Gratings ◽  
Space Applications ◽  
Long Period ◽  
Long Period Fiber Gratings

This work presents an experimental study on the effects of gamma radiation on Long Period Fiber Gratings (LPFGs) in a low-dose test campaign to evaluate their eventual degradation. The study was carried out with standard single-mode fibers where the grating was inscribed using the Electric-Arc Discharge (EAD) technique. Before the gamma campaign, a detailed optical characterization was performed with repeatability tests to verify the accuracy of the setup and the associated error sources. The gamma-induced changes up to a dose of 200 krad and the recovery after radiation were monitored with the Dip Wavelength Shift (DWS). The results show that the gamma sensitivity for a total dose of 200 krad is 11 pm/krad and a total DWS of 2.3 nm has been observed with no linear dependence. Post-radiation study shows that recovery from radiation-induced wavelength shift is nearly complete in about 4000 h. Experimental results show that the changes suffered under gamma irradiation of these LPFGs are temporary making them a good choice as sensors in space applications.

scholarly journals Sensing and Demodulation of Special Long-Period Fiber Gratings Induced by ScanningCO2Laser Pulses

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Tao Zhu ◽  
Leilei Shi ◽  
Min Liu ◽  
Wei Huang
Keyword(s):  
Single Mode ◽  
Laser Pulses ◽  
Single Mode Fiber ◽  
Wavelength Shift ◽  
Refractive Index Sensor ◽  
Fiber Gratings ◽  
Long Period ◽  
Investigation Methods ◽  
Long Period Fiber Gratings ◽  
Sensor Strain

A review of long-period fiber gratings (LPFGs) with special structures induced by scanning CO2laser pulses in single mode fiber (SMF) is presented in this paper. In the first part, the special structures and fabrication methods of LPFGs are demonstrated in detail. Next, the special LPFG-based sensors are demonstrated, such as refractive index sensor, strain sensor with temperature compensation, and torsion sensor without temperature crosstalking. Finally, several investigation methods including intensity, wavelength shift, and fiber ring laser demodulation are discussed.

scholarly journals Arc-Induced Long-Period Fiber Gratings at INESC TEC. Part I: Fabrication, Characterization and Mechanisms of Formation

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4914
Author(s):  
Gaspar Rego ◽  
Paulo Caldas ◽  
Oleg V. Ivanov
Keyword(s):  
Arc Discharge ◽  
Electric Arc ◽  
Transmission Spectra ◽  
Fiber Gratings ◽  
Long Period ◽  
Electric Arc Discharge ◽  
Mechanisms Of Formation ◽  
Long Period Fiber Gratings ◽  
Fabrication Parameters

In this work, we reviewed the most important achievements of INESC TEC related to the fabrication of long-period fiber gratings using the electric arc technique. We focused on the fabrication setup, the type of fiber used, and the effect of the fabrication parameters on the gratings’ transmission spectra. The theory was presented, as well as a discussion on the mechanisms responsible for the formation of the gratings, supported by the measurement of the temperature reached by the fiber during an electric arc discharge.

scholarly journals Ultrashort Long-Period Fiber Gratings Inscribed on a Single-Mode Fiber for Torsion Sensing Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Marta Nespereira ◽  
João M. P. Coelho ◽  
José Manuel Rebordão
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Wavelength Shift ◽  
Fiber Grating ◽  
Long Period ◽  
Sensing Applications ◽  
High Tension ◽  
Long Period Fiber Gratings ◽  
Order Of Magnitude ◽  
Period Fiber Grating

The response of ultrashort-length CO2-induced long-period fiber grating (LPFG) sensors to torsion is reported. While engraving using CO2 laser radiation, the fiber is submitted to high tension allowing the obtainment of gratings with shorter lengths, down to 2.4 mm, which is almost one order of magnitude lower than the usual. Also, the fiber is only irradiated in one side, creating an asymmetrical profile leading to highly birefringent gratings. Sensitivity to axial twists is demonstrated, with values up to 0.15 nm/(rad/m) for the resonant wavelength shift and higher than 0.03 dBm/(rad/m) for the variation in the intensity (attenuation). Discrimination between rotation directions, clockwise and counterclockwise, was observed.

Electric-arc-induced long period fiber gratings for gain equalization of erbium-doped optical amplifiers

2007 ◽  
Author(s):  
I. Cacciari ◽  
M. Brenci ◽  
R. Falciai ◽  
G. Nunzi Conti ◽  
S. Pelli ◽  
...  
Keyword(s):  
Optical Amplifiers ◽  
Electric Arc ◽  
Fiber Gratings ◽  
Long Period ◽  
Erbium Doped ◽  
Long Period Fiber Gratings ◽  
Gain Equalization
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