Characterization of Encapsulating Materials for Fiber Bragg Grating-Based Temperature Sensors

Abstract

An experimental study has been carried out for the characterization of encapsulating materials for fiber Bragg grating-based temperature sensors to prevent the formation of micro-cracks and devitrification on the fiber surface at elevated temperatures by making use of a rigid probe. The developed sensor probe was configured by encapsulating a type 1 fiber Bragg grating with an aluminum nitride tube and is used to measure temperatures from 20°C to 500°C. The adapted encapsulation technique validated the sensor to achieve linearity of 99.979%, sensitivity of 14.03 ± 0.02 pm/°C, and good repeatability; its practical use in harsh environments is predicted.

Keywords:

• fiber Bragg grating
• fiber-optic sensors
• temperature sensor probe

Acknowledgments

The authors thank Dr. Balaji Srinivasan, Department of Electrical Engineering, IIT Madras, for sparing FBGs and Mr. Jude Benedict, Fatima Industrial Training Institute, Kazipet, for providing fabrication facilities.

Funding

The authors acknowledge the fine gesture of Department of Electronics & Information Technology (DEIT) under the Ministry of Communications and Information Technologies, New Delhi, for providing financial assistance to carry out this work.

Additional information

Notes on contributors

Venkata Reddy Mamidi

Venkata Reddy Mamidi received his B.Sc. from Osmania University, Hyderabad, India, in 2008 and his M.Sc. (Tech.) in engineering physics with instrumentation specialization from National Institute of Technology, Warangal, India, in 2011. He is currently pursuing his Ph.D. at the Department of Physics, NIT, Warangal. His research interests include optical fiber sensors and its applications, electrostatics, and optoelectronic instrumentation. He is a member of SPIE and OSA.

Srimannarayana Kamineni

Srimannarayana Kamineni received his B.Sc. from Andhra University, Visakhapatnam, in 1971 and his M.Sc. (Tech.) and Ph.D. in engineering physics in the fields of photonics and holography for non-destructive testing from Regional Engineering College (now NIT), Warangal, in 1974 and 1978, respectively. He has been a faculty member of the Physics Department at National Institute of Technology, Warangal, since 1977 and is presently working as a professor. His research interests are in the areas of fiber-optic sensors, passive components in telecommunications, optical techniques in precision measurements, laser metrology, and holography for NDT. He is a member of SPIE and OSA.

L. N. Sai Prasad Ravinuthala

L. N. Sai Prasad Ravinuthala received his B.Sc. from Sri Venkateswara University, Tirupati, India, in 1976 and his M.Sc. from Andhra University, Visakhapatnam, in 1979. He completed his Ph.D. at Regional Engineering College (now NIT), Warangal, in 1985. He joined as a faculty member of NIT, Warangal, in 1986 and is presently working as a professor in the Department of Physics of that institute. His present research interest includes electronic instrumentation, holographic NDT, FBG sensors, and signal processing. He is a member of SPIE and ISTE.

Venkatapparao Thumu

Venkatapparao Thumu received his B.Sc. from Osmania University, Hyderabad, in 1983 and his M.Sc. in physics from Kakatiya University, Warangal, in 1987. He obtained his Ph.D. from Kakatiya University in 1994. He worked as a faculty member at Kakatiya University from 1994 to 2008. He has been working as an assistant professor at National Institute of Technology, Warangal, since 2008. His research interest includes highly correlated electron systems, optoelctronics, fiber-optic sensing, polymer degradation, polymer blends, and spintronic materials.

Vengal Rao Pachava

Vengal Rao Pachava received his B.Sc. and M.Sc. specializing in electronics and communications from Osmania University, Hyderabad, India, in 2004 and 2009, respectively. He is currently pursuing his Ph.D. while investigating the use of optical sensing techniques at the Department of Physics, NIT, Warangal, India. His research interests include low- and high-pressure sensing using fiber Bragg grating sensors. He is a fellow of Optical Society of India, a member of SPIE, and a member of OSA.