Open Access
Multiplexing of six micro-displacement suspended-core Sagnac interferometer sensors with a Raman-Erbium fiber laser
(Optical Society of America, 2013) Bravo Acha, Mikel; Fernández Vallejo, Montserrat; Echapare Zabaleta, Mikel; López-Amo Sáinz, Manuel; Kobelke, J.; Schuster, K.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This work experimentally demonstrates a long-range optical fiber sensing network for the multiplexing of fiber sensors based on photonic crystal fibers. Specifically, six photonic crystal fiber sensors which are based on a Sagnac interferometer that includes a suspended-core fiber have been used. These sensors offer a high sensitivity for microdisplacement measurements. The fiber sensor network presents a ladder structure and its operation mode is based on a fiber ring laser which combines Raman and Erbium doped fiber amplification. Thus, we show the first demonstration of photonic crystal fiber sensors for remote measurement applications up to 75 km.
Open Access
Control of the strain sensitivity using a suspended core photonic crystal fiber sensing head
(SPIE, 2014-06-02) Rota Rodrigo, Sergio; López-Amo Sáinz, Manuel; Kobelke, J.; Schuster, K.; Santos, José Luís; Frazão, Orlando; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work a strain sensor based on a suspended core fiber is proposed. The sensor comprises a suspended core PCF between SMFs and is based on the multimode interference generated in these transitions. A strain sensitivity study for different sensing heads and stage separation lengths was carried out showing a sensitivity of -2.42 pm/με for the best case. Also the sensing head was tested for curvature and temperature, showing in the first case that it is insensitive to curvature effects, and secondly, that for small sensor lengths it was insensitive to temperature variations.
Open Access
Simultaneous strain and temperature measure based on a single suspended core photonic crystal fiber
(SPIE, 2014-06-02) Rota Rodrigo, Sergio; López-Amo Sáinz, Manuel; Kobelke, J.; Schuster, K.; Santos, José Luís; Frazão, Orlando; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work a simultaneous strain and temperature sensor based on a suspended core fiber is proposed. The sensor comprises a 3mm suspended core PCF between SMFs and is based on the combination of two multimodal interferences with different frequency fringe patterns. The interference of the both signal has different sensitivity responses to strain and temperature. Thought a low-pass frequency filtering of the detected spectrum, the wavelength shift of the two interferences can be measured allowing the discrimination of strain and temperature simultaneously. The resolutions of this sensor are 0.45 ºC and 4.02 με.
Open Access
Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror
(Elsevier, 2015) Pérez Herrera, Rosa Ana; André, R. M.; Silva, S. F.; Becker, M.; Schuster, K.; Kobelke, J.; López-Amo Sáinz, Manuel; Santos, José Luís; Frazão, Orlando; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, two all-fiber loop mirrors using a clover microstructured fiber for the simultaneous measurement of temperature and strain are presented. The sensing heads are formed by a short piece of clover microstructured fiber with 35 mm and 89 mm length respectively. The geometry of the fiber allowed observing different interferences created by the microstructured fiber core section. Different sensitivities to temperature and strain were obtained and, using a matrix method, it is possible to discriminate both physical parameters. Resolutions of ±2ºC and ±11 μ for the first structure and ±2.3ºC and ±18 μ for the second one, for temperature and strain, respectively, were attained.
Open Access
Suspended-core fiber Sagnac combined dual-random mirror Raman fiber laser
(Optical Society of America, 2011) Rodrigues Pinto, Ana Margarida; Bravo Acha, Mikel; Fernández Vallejo, Montserrat; López-Amo Sáinz, Manuel; Kobelke, J.; Schuster, K.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In the present work, a multiwavelength fiber laser based in the combination of a double-random mirror and a suspended-core Sagnac interferometer is presented. The double-random mirror acts by itself as a random laser, presenting a 30dB SNR, as result of multiple Rayleigh scattering events produced in the dispersion compensating fibers by the Raman amplification. The suspended-core fiber Sagnac interferometer provides the multi peak channeled spectrum, which can be tuned by changing the length of the fiber. The result of this combination is a stable multiwavelength peak laser with a minimum of ~25dB SNR, which is highly sensitive to polarization induced variations.