Fiber Loop Mirror Using a Small Core Microstructured Fiber for Strain and Temperature Discrimination

Abstract

In this work, a fiber loop mirror for the simultaneous measurement of strain and temperature is presented. The loop mirror contains a section of a small core microstructured fiber characterized for strain and temperature sensing. Due to the small core geometry and using a small section length, the structure presents high birefringence and also intermodal interference. The spectral response of this configuration shows the presence of three interferometers. One of them corresponds to the interference of light that propagates in the fast and slow axes (group birefringence) and the others are associated with the interference of light in the two lowest order spatial modes in each of the fiber eigenaxis. These interferometers present distinct sensitivities to strain and temperature for different wavelengths.

Interrogation Sensing Scheme Based on a Figure-of-Eight Fiber Loop Mirror

“…FLMs can incorporate within the loop a length of highly-birefringent (HiBi) fiber, which reveals several advantages, such as, input polarization independence and high extinction ratio. Besides the gyroscope application [1], various kinds of fiber optic sensors based on FLMs have been demonstrated, such as temperature [4], [5], strain [6]- [8], pressure [9], liquid level [10], biochemical [11], UV [12] and multiparameter sensor [13], [14].…”

High-Birefringent Fiber Loop Mirror Sensors: New Developments

“…Breakthrough of Hi-Bi FLM configurations 1997 Temperature sensor ; temperature sensing in NIR ; strain sensor (Campbell et al, 1997(Campbell et al, ) 1999 Strain sensor (Campbell et al, 1999) 2004 Temperature PCF sensor (Kim, D. H. & Kang, 2004); temperature insensitivity using PCF (Zhao et al, 2004(Zhao et al, ) 2005 Interrogation system using PCF (Yang et al, 2005); displacement sensor (Liu et al, 2005) 2006 Liquid level sensor (Dong, B. et al, 2006); FBG interrogation system ; LPG/Hi-Bi FLM (Frazao et al, 2006b) 2007 Review of Hi-Bi FLM sensors (Frazao et al, 2007a); strain PCF sensor (Dong, X. Y. et al, 2007;Frazao et al, 2007b) ; chemical etching (Frazao et al, 2007c); concatenated FLM (Frazao et al, 2007d) 2008 Temperature Erbium Hi-Bi fiber (Frazao et al, 2008a); refractive index sensor (Frazao et al, 2008b); multiparameter sensor using side-hole fiber (Frazao et al, 2008c); pressure PCF sensor (Fu et al, 2008); FBG/Hi-Bi FLM (Zhou et al, 2008); current sensor (Marques et al, 2008) 2009 Multiplexing Hi-Bi FLM (Fu et al, 2009); strain and temperature discrimination using two Hi-Bi fibers ); hollow-core PCF sensor (Kim, G. et al, 2009); holey fiber filled with metal indium (Kim, B. H. et al, 2009) 2010 Torsion PCF sensor ; curvature PCF sensor (Gong et al, 2010); pressure-induced SMF ; long distance remote interrogation system (Lee et al, 2010); small core PCF (Andre et al, 2010); intensity strain sensor (Qian et al, 2010); suspended twin-core ; displacement PCF sensor 2011 Hi-Bi FLM with an output port probe ; LPG/Sagnac Loop (Kang et al, 2011); curvature PCF sensor (Hwang et al, 2011); Hi-Bi photonic bandgap Bragg fiber …”

“…A temperature-independent strain sensor based on intensity measurements was developed (Qian et al, 2010). A small core microstructured fiber segment in the FLM for the simultaneous measurement of strain and temperature was used (Andre et al, 2010). Besides Hi-Bi, this configuration also showed intermodal interference, resulting in a complex channeled spectrum.…”

Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror

“…FLMs made of highly birefringent fiber (HiBi-FLM) have several advantages, including input polarization independence and high extinction ratio. Besides the gyroscope application, various kinds of sensors based on FLMs have been realized [3], such as temperature sensors [2,4], strain sensors [5,6], pressure sensors, liquid level sensors [7], biochemical sensors, UV detection [8] and multiparameter measurement [9][10][11].…”