Ultrafast femtosecond-laser-induced fiber Bragg gratings in air-hole microstructured fibers for high-temperature pressure sensing

We present fiber Bragg grating pressure sensors in air-hole microstructured fibers for high-temperature operation above 800°C. An ultrafast laser was used to inscribe Type II grating in two-hole optical fibers. The fiber Bragg grating resonance wavelength shift and peak splits were studied as a function of external hydrostatic pressure from 15 psi to 2000 psi. The grating pressure sensor shows stable and reproducible operation above 800°C. We demonstrate a multiplexible pressure sensor technology for a high-temperature environment using a single fiber and a single-fiber feedthrough. © 2010 Optical Society of America

A fiber-integrated quantum memory for telecom light

We demonstrate the storage and on-demand retrieval of single-photon-level telecom pulses in a fiber cavity. The cavity is formed by fiber Bragg gratings at either end of a single-mode fiber. Photons are mapped into, and out of, the cavity using quantum frequency conversion driven by intense control pulses. In a first, spliced-fiber, cavity we demonstrate storage up to 0.55$\mu$s (11 cavity round trips), with $11.3 \pm 0.1$% total memory efficiency, and a signal-to-noise ratio of $12.8$ after 1 round trip. In a second, monolithic cavity, we increase this lifetime to 1.75$\mu$s (35 round trips) with a memory efficiency of $12.7 \pm 0.2$ (SNR of $7.0 \pm 0.2$) after 1 round trip. Fiber-based cavities for quantum storage at telecom wavelengths offer a promising route to synchronizing spontaneous photon generation events and building scalable quantum networks.Comment: 8 pages, 7 figure

High Temperature Long Period Grating Thermo-Mechanically Written

An optical fiber transducer able to work in high temperature environments is experimentally demonstrated in the laboratory. It is based on a permanent long period grating (LPG) written using a new technique based on a thermo-mechanical approach. Device precision was experimentally checked by means of repetitive thermal cycles between 25 and 950 °C. In addition device stability was assured by maintaining the temperature in steady state at 800 °C during 23 hours

Tapered Optical Fiber Sensor for Label-Free Detection of Biomolecules

This paper presents a fast, highly sensitive and low-cost tapered optical fiber biosensor that enables the label-free detection of biomolecules. The sensor takes advantage of the interference effect between the fiber’s first two propagation modes along the taper waist region. The biomolecules bonded on the taper surface were determined by demodulating the transmission spectrum phase shift. Because of the sharp spectrum fringe signals, as well as a relatively long biomolecule testing region, the sensor displayed a fast response and was highly sensitive. To better understand the influence of various biomolecules on the sensor, a numerical simulation that varied biolayer parameters such as thickness and refractive index was performed. The results showed that the spectrum fringe shift was obvious to be measured even when the biolayer was only nanometers thick. A microchannel chip was designed and fabricated for the protection of the sensor and biotesting. Microelectromechanical systems (MEMS) fabrication techniques were used to precisely control the profile and depth of the microchannel on the silicon chip with an accuracy of 2 μm. A tapered optical fiber biosensor was fabricated and evaluated with an Immune globulin G (IgG) antibody-antigen pair

A high-temperature fiber sensor using a low cost interrogation scheme

Regenerated Fibre Bragg Gratings have the potential for high-temperature monitoring. In this paper, the inscription of Fibre Bragg Gratings (FBGs) and the later regeneration process to obtain Regenerated Fiber Bragg Gratings (RFBGs) in high-birefringence optical fiber is reported. The obtained RFBGs show two Bragg resonances corresponding to the slow and fast axis that are characterized in temperature terms. As the temperature increases the separation between the two Bragg resonances is reduced, which can be used for low cost interrogation. The proposed interrogation setup is based in the use of optical filters in order to convert the wavelength shift of each of the Bragg resonances into optical power changes. The design of the optical filters is also studied in this article. In first place, the ideal filter is calculated using a recursive method and defining the boundary conditions. This ideal filter linearizes the output of the interrogation setup but is limited by the large wavelength shift of the RFBG with temperature and the maximum attenuation. The response of modal interferometers as optical filters is also analyzed. They can be easily tuned shifting the optical spectrum. The output of the proposed interrogation scheme is simulated in these conditions improving the sensitivity.The authors wish to acknowledge the financial support of the Infraestructura FEDER UPVOV08-3E-008, FEDER UPVOV10-3E-492, the Spanish MCINN through the project TEC2011-29120-C05-05 and the Valencia Government through the Ayuda Complementaria ACOMP/2013/146. The authors also acknowledge the collaboration of Alvarez from Fibercore for providing the high birefringence optical fiber.Barrera Vilar, D.; Sales Maicas, S. (2013). A high-temperature fiber sensor using a low cost interrogation scheme. Sensors. 13(9):11653-11659. https://doi.org/10.3390/s130911653S1165311659139Erdogan, T., Mizrahi, V., Lemaire, P. J., & Monroe, D. (1994). Decay of ultraviolet‐induced fiber Bragg gratings. Journal of Applied Physics, 76(1), 73-80. doi:10.1063/1.357062Butov, O. V., Dianov, E. M., & Golant, K. M. (2006). Nitrogen-doped silica-core fibres for Bragg grating sensors operating at elevated temperatures. Measurement Science and Technology, 17(5), 975-979. doi:10.1088/0957-0233/17/5/s06Grobnic, D., Mihailov, S. J., Smelser, C. W., & Ding, H. (2004). Sapphire Fiber Bragg Grating Sensor Made Using Femtosecond Laser Radiation for Ultrahigh Temperature Applications. IEEE Photonics Technology Letters, 16(11), 2505-2507. doi:10.1109/lpt.2004.834920Canning, J., Stevenson, M., Bandyopadhyay, S., & Cook, K. (2008). Extreme Silica Optical Fibre Gratings. Sensors, 8(10), 6448-6452. doi:10.3390/s8106448Cook, K., Shao, L.-Y., & Canning, J. (2012). Regeneration and helium: regenerating Bragg gratings in helium-loaded germanosilicate optical fibre. Optical Materials Express, 2(12), 1733. doi:10.1364/ome.2.001733Lindner, E., Canning, J., Chojetzki, C., Brückner, S., Becker, M., Rothhardt, M., & Bartelt, H. (2011). Post-hydrogen-loaded draw tower fiber Bragg gratings and their thermal regeneration. Applied Optics, 50(17), 2519. doi:10.1364/ao.50.002519Trpkovski, S., Kitcher, D. J., Baxter, G. W., Collins, S. F., & Wade, S. A. (2005). High-temperature-resistant chemical composition Bragg gratings in Er^3+-doped optical fiber. Optics Letters, 30(6), 607. doi:10.1364/ol.30.000607Wang, T., Shao, L.-Y., Canning, J., & Cook, K. (2013). Regeneration of fiber Bragg gratings under strain. Applied Optics, 52(10), 2080. doi:10.1364/ao.52.002080Barrera, D., Finazzi, V., Villatoro, J., Sales, S., & Pruneri, V. (2012). Packaged Optical Sensors Based on Regenerated Fiber Bragg Gratings for High Temperature Applications. IEEE Sensors Journal, 12(1), 107-112. doi:10.1109/jsen.2011.2122254Fernandez-Ruiz, M. R., Carballar, A., & Azana, J. (2013). Design of Ultrafast All-Optical Signal Processing Devices Based on Fiber Bragg Gratings in Transmission. Journal of Lightwave Technology, 31(10), 1593-1600. doi:10.1109/jlt.2013.2254467Barrera, D., Villatoro, J., Finazzi, V. P., Cárdenas-Sevilla, G. A., Minkovich, V. P., Sales, S., & Pruneri, V. (2010). Low-Loss Photonic Crystal Fiber Interferometers for Sensor Networks. Journal of Lightwave Technology, 28(24), 3542-3547. doi:10.1109/jlt.2010.209086