CO 2 -laser induced long-period fiber gratings in nano-engineered bend insensitive single-mode fiber

2012 ◽  
Author(s):  
Yunjiang Rao ◽  
Wenhua Wang ◽  
Zinan Wang ◽  
Kin Seng Chiang ◽  
Yuan Gong
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Gratings ◽  
Long Period ◽  
Long Period Fiber Gratings

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.

Simultaneous strain and temperature measurement by cascading few-mode fiber and single-mode fiber long-period fiber gratings

2014 ◽  
Vol 53 (30) ◽  
pp. 7045 ◽  
Author(s):  
Li Wang ◽  
Weigang Zhang ◽  
Biao Wang ◽  
Lei Chen ◽  
Zhiyong Bai ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Gratings ◽  
Long Period ◽  
Long Period Fiber Gratings

scholarly journals Helically twisted long-period fiber gratings of YOFC single-mode fiber with optical fiber welding machine

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Yunfeng Bai ◽  
Zelong He ◽  
Jiyuan Bai ◽  
Suihu Dang
Keyword(s):  
Single Mode ◽  
Resonance Wavelength ◽  
Single Mode Fiber ◽  
Resonant Peak ◽  
Fiber Grating ◽  
Fiber Gratings ◽  
Long Period ◽  
Welding Machine ◽  
Long Period Fiber Gratings ◽  
Period Fiber Grating

The single-mode fiber provided by YOFC inc is employed for spiral processing by commercial welding machine. It can clearly see the periods structure under the light, but there is no obvious deformation of the fiber core, cladding and surface morphology under a microscope. There is an obvious resonant peak near 1560 nm, half peak width is about 25 nm, the depth of the resonant peak closed to –26 dB, when the period is about 411 μm. It agrees with theoretical calculation results according to the long-period fiber grating coupled-mode theory. The resonance wavelength is caused by coupling between the fundamental mode and the LP14 mode. The responsivities of the helically twisted long-period fiber gratings (H-LPFG) for the temperature is measured, the resonance wavelength is linear with temperature, the slope is 86 pm/℃. Because it is easy to inscribe by commercial welding machine, and has a strong resonance peak, it has potential applications as the temperature sensor.

scholarly journals Temperature Stability and Spectral Tuning of Long Period Fiber Gratings Fabricated by Femtosecond Laser Direct Writing

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3898
Author(s):  
Duarte Viveiros ◽  
José M. M. M. de Almeida ◽  
Luís Coelho ◽  
Helena Vasconcelos ◽  
João M. Maia ◽  
...  
Keyword(s):  
Temperature Stability ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fine Tuning ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Fiber Gratings ◽  
Long Period ◽  
Long Period Fiber Gratings ◽  
Temperature Ranges

Long period fiber gratings (LPFGs) were fabricated in a standard single mode fiber (SMF-28e) through femtosecond (fs) laser direct writing. LPFGs with longer and shorter periods were fabricated, which allows coupling from the fundamental core mode to lower and higher order asymmetric cladding modes (LP1,6 and LP1,12, respectively). For the grating periods of 182.7 and 192.5 µm, it was verified that the LP1,12 mode exhibits a TAP at approximately 1380 and 1448 nm in air and water, respectively. Characterization of the LPFGs subjected to high-temperature thermal treatment was accomplished. Fine-tuning of the resonance band’s position and thermal stability up to 600 °C was shown. The temperature sensitivity was characterized for the gratings with different periods and for different temperature ranges. A maximum sensitivity of −180.73, and 179.29 pm/°C was obtained for the two resonances of the 182.7 µm TAP LPFG, in the range between 250 and 600 °C.

Temperature sensing on tapered single mode fiber using mechanically induced long period fiber gratings

2015 ◽  
Author(s):  
Sigifredo Marrujo-García ◽  
Jesús Salvador Velázquez-González ◽  
María Guadalupe Pulido-Navarro ◽  
Ernesto González-Ocaña ◽  
Saúl Mújica-Ascencio ◽  
...  
Keyword(s):  
Single Mode ◽  
Single Mode Fiber ◽  
Temperature Sensing ◽  
Fiber Gratings ◽  
Long Period ◽  
Long Period Fiber Gratings

scholarly journals Ultrashort Long-Period Fiber Grating Sensors Inscribed on a Single Mode Fiber Using CO2 Laser Radiation

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Marta Nespereira ◽  
João M. P. Coelho ◽  
Manuel Abreu ◽  
José Manuel Rebordão
Keyword(s):  
Laser Radiation ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Fiber Grating ◽  
Fiber Gratings ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Long Period Fiber Gratings ◽  
Co2 Laser Radiation ◽  
Period Fiber Grating

Sensing performances of ultrashort (as low as 2.4 mm) long-period fiber gratings fabricated with CO2 laser radiation using commercial single mode fibers are presented. These lengths are, to our knowledge, the shortest of those found in the literature for this kind of sensors, approaching those typical in fiber Bragg gratings. Sensitivity to temperature and refractive index are demonstrated, with performances within the range expected for a single LPFG written on a single mode fiber without any enhancing technique. Analysis on results is made based on both theoretical and experimental data.

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.

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