Low-Cost Interrogation System for Long-Period Fiber Gratings Applied to Remote Sensing

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.

[1]  Ronald Pirich,et al.  Fiber optics for harsh environments , 2011, 2011 IEEE Long Island Systems, Applications and Technology Conference.

[2]  Nezih Mrad,et al.  Interrogation of a long-period grating using a mechanically scannable arrayed waveguide grating and a sampled chirped fiber Bragg grating. , 2008, Optics letters.

[3]  David J. Webb,et al.  The interrogation and multiplexing of long period grating curvature sensors using a Bragg grating based, derivative spectroscopy technique , 2004 .

[4]  J. M. Baptista,et al.  Long-Period Gratings Dynamic Interrogation With Modulated Fiber Bragg Gratings and Optical Amplification , 2012, IEEE Sensors Journal.

[5]  Qi Wang,et al.  Mini review: Recent advances in long period fiber grating biological and chemical sensors , 2018, Instrumentation Science & Technology.

[6]  Om Prakash,et al.  Quantification of Chloride and Iron in Sugar factory effluent using Long period fiber grating chemical sensor , 2018 .

[7]  Alan Richard Wilson,et al.  Corrosion Onset Detection Sensor , 2017, IEEE Sensors Journal.

[8]  Yan Tang,et al.  A Fe-C coated long-period fiber grating sensor for corrosion-induced mass loss measurement. , 2016, Optics letters.

[9]  José M. M. M. de Almeida,et al.  Low-Cost Interrogation System for Long Period Fiber Gratings as Sensing Devices , 2018 .

[10]  Dominique Thierry,et al.  Development of Wireless and Passive Corrosion Sensors for Material Degradation Monitoring in Coastal Zones and Immersed Environment , 2016, IEEE Journal of Oceanic Engineering.

[11]  I. Bennion,et al.  Comparison between femtosecond laser and fusion-arc inscribed long period gratings in photonic crystal fibre , 2009, Optics + Optoelectronics.

[12]  M. Lopez-Amo,et al.  New interrogation technique for multiplexing LPG-fiber loop mirrors based displacement sensors using an OTDR , 2011, 2011 IEEE SENSORS Proceedings.

[13]  Yun Li,et al.  PID control system analysis, design, and technology , 2005, IEEE Transactions on Control Systems Technology.

[14]  Junnan Li,et al.  A review of fiber-optic corrosion sensor in civil engineering , 2018 .

[15]  Gaspar M. Rego,et al.  Arc-Induced Long Period Fiber Gratings , 2016, J. Sensors.

[16]  P. Jorge,et al.  Real-Time Early Warning Strategies for Corrosion Mitigation in Harsh Environments , 2018, Journal of Lightwave Technology.

[17]  Julien Perchoux,et al.  Effect of injection current and temperature on signal strength in a laser diode optical feedback interferometer. , 2015, Applied optics.

[18]  A. Vengsarkar,et al.  Optical fiber long-period grating sensors. , 1996, Optics letters.

[19]  Jianping Yao,et al.  Interrogation of a Long-Period Grating Sensor by a Thermally Tunable Arrayed Waveguide Grating , 2008, IEEE Photonics Technology Letters.

[20]  J. Judkins,et al.  Long-period fiber gratings as band-rejection filters , 1995 .

[21]  V. Bhatia.  Applications of long-period gratings to single and multi-parameter sensing. , 1999, Optics express.

[22]  Francesco Baldini,et al.  Towards a Uniform Metrological Assessment of Grating-Based Optical Fiber Sensors: From Refractometers to Biosensors , 2017, Biosensors.

[23]  R. I. Mata-Chávez,et al.  Long Period Fiber Grating Produced by Arc Discharges , 2012 .