Abstract
Traditionally, uorescence-based analytical methods were associated with high-cost bulky laboratory equipment. However, a diversity of technological advances taking place over the last 20 years concurred to change this picture. In the eld of optoelectronics, the advent of low-cost blue and UV lasers and LEDs, together with new miniature CCD spectrometers and high-sensitivity avalanche photodiodes (APDs), is enabling a new generation of spectroscopy tools to be developed and deployed in eld applications. On the other hand, chemistry and material sciences are delivering new types of uorescent materials with enhanced sensing properties, such as long-lived metallo-organic complexes or highly photostable quantum dots (QDs). Such developments are expanding the uses of uorescence and enabling new applications such as long-term multiwavelength imaging, ow cytometry analysis in microuidic chips, high-throughput DNA sequencing, and ber-optic-based diagnostic probes. © 2015 by Taylor and Francis Group, LLC.

Abstract
This work presents a demonstration of the potential of fiber cavity ring-down for remote sensing, by using an OTDR to send impulses down similar to 20 km of optical fiber at the end of which the fiber ring cavity was placed. The OTDR showed almost no losses in the fiber, so other ring-down cavities could be spliced along the same fiber. To study the sensitivity of the cavity ring an intensity sensor based on a taper was placed in the ring and glued to a translation stage. A displacement of the stage imposes a curvature on the taper and an associated loss. The configuration had a sensitivity of (11.8 +/- 0.5) mu s/mm.

Abstract
An interferometric Fabry-Perot cavity based on hollow-core ring photonic crystal fiber combined with a silicone diaphragm is proposed for low pressure sensing. The sensor exhibits a sensitivity of 0.086 nm/mmHg for a pressure range between 0 and 337.5 mmHg. These values are in the range of physiological pressures, such as intravascular pressure. (C) 2014 Wiley Periodicals, Inc.

Abstract
This work presents a fiber CRD configuration for the measurement of strain. An Optical Time-Domain Reflectometer was used to send impulses down into the fiber loop cavity, inside of which a chirped fiber Bragg grating was placed to act as a strain sensing element. This technique could provide strain results with both conventional CRD-based configuration and the OTDR.

Abstract
This work presented a demonstration of the potential for a fiber based cavity ring-down (CRD) using an optical time-domain reflectometer (OTDR). The OTDR was used to send the impulses down into about 20 km of a standard single optical fiber, at the end of which the fiber cavity ring-down was placed. The OTDR measured no appreciable losses, so other CRDs multiplexed could be spliced in parallel along the same optical fiber. To demonstrate the behavior and sensitivity of the proposed configuration, a displacement sensor based on a fiber taper with a diameter of 50 µm was placed inside the fiber loop, and the induced losses were measured on the CRD signal — a sensitivity of 11.8 ± 0.5 µs/mm was achieved. The dynamic range of the sensing head used in this configuration was about 2 mm. Finally, this work was also compared with different works published in the literature. © 2014, The Author(s).

Abstract
Focused ion beam technology is combined with chemical etching of specifically designed fibers to create Fabry-Perot interferometers. Hydrofluoric acid is used to etch special fibers and create microwires with diameters of 15 mu m. These microwires are then milled with a focused ion beam to create two different structures: an indented Fabry-Perot structure and a cantilever Fabry-Perot structure that are characterized in terms of temperature. The cantilever structure is also sensitive to vibrations and is capable of measuring frequencies in the range 1 Hz - 40 kHz. (C) 2014 Optical Society of America