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New Challenges in the European Area: Young Scientists 1st International Baku Forum 2013| May 20 - 25, 2013 NANOWIRES IN SUSPENDED-CORE FIBER FOR NEW HIGH SENSITIVITY OPTICAL SENSORS Ricardo M. André [email protected] Portugal Contents • • • • Optical Fibers; Optical Fiber Sensors; Microstructured Optical Fibers; Suspended Core Fibers: – – – – Tapering; Setup; Spectral Response; Strain and Temperature Characterization; • Conclusions. April 8th/9th, 2013 Ricardo Melo André 2/13 Optical Fiber • Different refractive índices in core and cladding; • Propagation by total internal reflection. n1 n2 n1 18 de Fevereiro de 2012 Ricardo André - ENEF XII 3/14 Optical Fiber Sensors • How can we use Optical Fibers as sensors? DL/L DT Ricardo Melo André - IJUP 2010 - February 18 2010 4 Microstructured Optical Fibers (MOFs) • Photonic Crystal Fibers (PCFs): – Index guiding PCFs – Photonic bandgap PCFs. • Other MOFs: – Suspended Core Fibers, Bragg Fibers and others. 18 de Fevereiro de 2012 Ricardo André - ENEF XII 5/14 Tapering of Suspended Core Fiber • VYTRAN GPX-3000 – Tapering of microstructured optical fibers with extreme control; April 8th/9th, 2013 Ricardo Melo André 6/13 Suspended Core Fiber Tapers • Tapers down to 20 μm of external diameter: – Nanocore diameter of 330 nm. • No hole collapse; • Cladding guidance below 600-700 nm core. 125 μm fiber April 8th/9th, 2013 2.1 μm core Ricardo Melo André 810 nm fiber 7/13 Fiber Loop Mirror Setup • Erbium-doped broadband source (1550 nm); • Optical Spectrum Analyzer April 8th/9th, 2013 • 3 dB coupler; • Polarization controller; • Suspended-core fiber section with taper. Ricardo Melo André 8/13 Spectral Response Analysis • Two interferometers: – High Birefringence; – Intermodal Interference; • Higher visibility; • Cleaner spectrum (only birefringence). April 8th/9th, 2013 Ricardo Melo André 9/13 Strain Characterization • Strain sensitivity increase with taper waist diameter decrease. • 2.1 μm core – 0.718 pm/με • 810 nm core – 2.41 pm/με April 8th/9th, 2013 Ricardo Melo André 10/13 Temperature Characterization • 2.1 μm core – 2.1 pm/K • 810 nm core – 56.2 pm/K • At lower diameters, higher birefringence dependence on temperature. April 8th/9th, 2013 Ricardo Melo André 11/13 Conclusions • Nanowire Characteristics: – High degree of protection / Independence of external medium; – Triangular, highly birefringent shape; – High temperature sensitivity; – Enhanced strain sensitivity; – High spectral stability; – Clean and easy-to-read spectrum; April 8th/9th, 2013 Ricardo Melo André 12/13 Acknowledgments • COST TD1001 Information and Communication Technologies; • Institute of Photonic Technology, Jena, Germany; • Dr. Orlando Frazão and Prof. Manuel B. Marques; • Thanks for your attention. April 8th/9th, 2013 Ricardo Melo André 13/13