scholarly journals Transverse Load and Temperature Sensing Using Multiplexed Long-Period Fiber Gratings

Photonics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Ismael Torres-Gómez ◽  
Alejandro Martínez-Rios ◽  
Gilberto Anzueto-Sánchez ◽  
Daniel. E. Ceballos-Herrera ◽  
Guillermo Salceda-Delgado
Keyword(s):  
Simultaneous Measurement ◽  
Room Temperature ◽  
Transverse Load ◽  
Fiber Grating ◽  
Fiber Gratings ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Sensing Applications ◽  
Long Period Fiber Gratings ◽  
Period Fiber Grating

The simultaneous measurement of transverse load and temperature using two long-period fiber gratings multiplexed in the wavelength domain is presented experimentally. For this, a mechanically induced long-period fiber grating (MI-LPFG) and a long-period fiber grating inscribed by a continuous-wave CO2 laser (CO2 LPFG) are connected in cascade. First, the transverse load and the temperature measurements were individually performed by the multiplexed long-period fiber gratings configuration. The MI-LPFG is subject to a transverse load variation from 0–2000 g with steps of 500 g, whereas the CO2 LPFG is unloaded and they are kept at room temperature. Similarly, the CO2 LPFG is subject to a temperature variation from 30 to 110 °C by increments of 20 °C, while the MI-LPFG with a constant transverse load of 2000 g is kept at room temperature. Subsequently, the simultaneous measurement of the transverse load and the temperature is performed by the multiplexed long-period fiber grating following the steps outlined above. According to the experimental results, the transverse load and temperature measurement present high repeatability for the individual and simultaneous process. Moreover, the multiplexed LPFGs exhibit low cladding-mode crosstalk of transverse load and temperature. The coarse wavelength-division multiplexing (CWDM) of long-period fiber gratings is an attractive alternative technique in optical fiber distributed sensing applications.

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

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3003 ◽  
Author(s):  
Jian Tang ◽  
Cailing Fu ◽  
Zhiyong Bai ◽  
Changrui Liao ◽  
Yiping Wang
Keyword(s):  
Refractive Index ◽  
Fiber Grating ◽  
Fiber Gratings ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Long Period Fiber Gratings ◽  
Fs Laser ◽  
Period Fiber Grating ◽  
Application Fields ◽  
Sensing Characteristics

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.

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 Simulation of the Transmission Spectrum of Long-Period Fiber Gratings Structures with a Propagating Acoustic Shock Front

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7212
Author(s):  
Oleg V. Ivanov ◽  
Paulo Caldas ◽  
Gaspar Rego
Keyword(s):  
Shock Front ◽  
Transmission Spectrum ◽  
Fiber Grating ◽  
Modulation Amplitude ◽  
Fiber Gratings ◽  
Coupled Mode ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Long Period Fiber Gratings ◽  
Period Fiber Grating

In this paper, we investigate modification of transmission spectra of long-period fiber grating structures with an acoustic shock front propagating along the fiber. We simulate transmission through inhomogeneous long-period fiber gratings, π-shift and reflective π-shift gratings deformed by an acoustic shock front. Coupled mode equations describing interaction of co-propagating modes in a long-period fiber grating structures with inhomogeneous deformation are used for the simulation. Two types of apodization are considered for the grating modulation amplitude, such as uniform and raised-cosine. We demonstrate how the transmission spectrum is produced by interference between the core and cladding modes coupled at several parts of the gratings having different periods. For the π-shift long-period fiber grating having split spectral notch, the gap between the two dips becomes several times wider in the grating with the acoustic wave front than the gap in the unstrained grating. The behavior of reflective long-period fiber gratings depends on the magnitude of the phase shift near the reflective surface: an additional dip is formed in the 0-shift grating and the short-wavelength dip disappears in the π-shift grating.

Simultaneous Measurement of Torsion and Temperature Based on π-Phase-Shifted Long-Period Fiber Grating Inscribed on Double-Clad Fiber

2021 ◽  
Vol 21 (8) ◽  
pp. 4243-4251
Author(s):  
Jinsil Han ◽  
Jihoon Kim ◽  
Seul-Lee Lee ◽  
Sungwook Choi ◽  
Yong Wook Lee
Keyword(s):  
Simultaneous Measurement ◽  
Room Temperature ◽  
Twist Angle ◽  
Optical Fiber Sensor ◽  
Resonance Wavelength ◽  
Fiber Grating ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Period Fiber Grating ◽  
Temperature Responses

In this work, we experimentally demonstrated an optical fiber sensor capable of performing simultaneous measurement of torsion and temperature using a π-phase-shifted long-period fiber grating (LPFG) inscribed on double-clad fiber (DCF), referred to as a PS-DC-LPFG. The fabricated PSDC- LPFG showed split attenuation bands near its resonance wavelength, and the two dips in these bands were selected as sensor indicators, denoted as Dips A and B, for the simultaneous measurement of torsion and temperature. The torsion and temperature responses of the two indicators were investigated in a twist angle range from −360° to 360° and a temperature range from 30 to 120 °C, respectively. When the twist angle increased from 0° to 360° (clockwise) at room temperature, both Dips A and B showed redshifts. On the contrary, when the twist angle decreased from 0° to −360° (counterclockwise), the two dips showed blueshifts. In terms of temperature responses, both dips showed redshifts with increasing ambient temperature while the sensor head (i.e., the PS-DC-LPFG) remained straight without any applied torsion. Owing to their linear and independent responses to torsion and temperature, the changes in torsion and temperature applied to the PSDC- LPFG could be simultaneously estimated from the measured wavelength shifts and calculated sensitivities of the two indicator dips.

Simultaneous measurement of directional torsion and temperature by using a DC-sampled helical long-period fiber grating

2021 ◽  
Vol 142 ◽  
pp. 107171
Author(s):  
Chengliang Zhu ◽  
Yong Zhao ◽  
Maoqing Chen ◽  
Ruijie Tong ◽  
Sheng Hu ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Fiber Grating ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Period Fiber Grating

scholarly journals Double Notched Long-Period Fiber Grating Characterization for CO2 Gas Sensing Applications †

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3206 ◽  
Author(s):  
Hsiang-Chang Hsu ◽  
Tso-Sheng Hsieh ◽  
Tzu-Hsuan Huang ◽  
Liren Tsai ◽  
Chia-Chin Chiang
Keyword(s):  
Gas Sensor ◽  
Transmission Loss ◽  
Gas Sensing ◽  
Fiber Grating ◽  
Co2 Gas ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Sensing Applications ◽  
Co2 Gas Sensor ◽  
Period Fiber Grating

In this study, we applied a double-sided inductively coupled plasma (ICP) process to nanostructure long-period fiber grating (LPFG) in order to fabricate a double-notched LPFG (DNLPFG) sensor with a double-sided surface corrugated periodic grating. Using the sol-gel method, we also added thymol blue and ZnO to form a gas sensing layer, thus producing a DNLPFG CO2 gas sensor. The resulting sensor is the first double-sided etching sensor used to measure CO2. The experimental results showed that as the CO2 concentration increased, the transmission loss increased, and that the smaller the fiber diameter, the greater the sensitivity and the greater the change in transmission loss. When the diameter of the fiber was 32 μm (and the period was 570 μm) and the perfusion rate of CO2 gas was 15%, the maximum loss variation of up to 3.881 dB was achieved, while the sensitivity was 0.2146 dB/% and the linearity was 0.992. These results demonstrate that the DNLPG CO2 gas sensor is highly sensitive.

Research of Simultaneous Measurement of Temperature and Strain of Fiber Optic Cable Material

2012 ◽  
Vol 507 ◽  
pp. 30-33
Author(s):  
Xue Jun Zhang ◽  
Hong Tao Guo
Keyword(s):  
Simultaneous Measurement ◽  
Fiber Optic ◽  
Fiber Grating ◽  
Mean Square ◽  
Fiber Optic Cable ◽  
Long Period Fiber Grating ◽  
Long Period ◽  
Polarization Maintaining Fiber ◽  
Polarization Maintaining ◽  
Period Fiber Grating

Simultaneous measurement of strain and temperature was demonstrated by using a long-period fiber grating inscribed on a polarization-maintaining fiber. This paper analyses the intersect senstive questions in terms of strain and temperature of fiber optic cable material. It also proposes a new way to carry out simultaneous measurements of strain and temperature. Experimental results show mean square deviations of 15.6 με and 0.7°C for strain and temperature, respectively.

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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