Abstract
Long period fibre gratings (LPFG) have found an increasing interest due to the easy fabrication in any kind of fibre through the induced electric arc technique with low cost and flexibility. They have been used in applications such as gain-flattening and band-rejection, and for sensing strain, temperature and chemical and biological parameters. The sensitivity of LPFG increases when the fibre is coated with certain thin films. In this short review it is presented the recent developments and applications of these kind of sensors.

Abstract
Optical Tweezers (OT) are able to trap/manipulate dielectric particles with few microns in a contactless manner due to forces exerted on them by a strongly focused optical beam. OT are being applied in Biology/Medicine, especially Optical Fiber Tweezers (OFT), for being simpler and more flexible than the conventional setups. Despite of the trapping phenomena of symmetrical particles by OFTs being already modeled, effects regarding complex bodies remain poorly understood. Here we provide a 2D characterization of the trapping forces exerted by a laser OFT on a geometric form of a Red Blood Cell (RBC), occupying different positions in a grid, using the method proposed by Barnett&Loudon. Comparisons were made between the forces exerted on a RBC having the mean normal size; a RBC with 80% of the normal size and an 1.5µm circular particle, due to the size and shape variability of biological-derived structures. The influence of RBCs inclination angles regarding its major axis on trapping performance was also evaluated for angles of p/4 and p/2. Simulation results showed that trapping phenomena are possible for all the conditions evaluated, as well as calculated trapping forces range was according with the literature (pN). We observed that, despite of modeled particles having the same optical characteristics, features such as particle geometry, size, position and inclination degree influence trapping. Trapping forces magnitude was higher for RBC relatively to the circular symmetrical particle; for large RBCs than RBCs with smaller dimensions; and for inclined RBCs than erythrocytes horizontally aligned. Those results reinforce the importance of modeling optical experiments to determine relevant parameters which affect trapping performance. © 2017 IEEE.

Abstract
A computational method for optical fiber trapping of healthy and Malariainfected blood cells characterization is proposed. A trapping force relation with the infection stage was found, which could trigger the development of a diagnostic sensor. © OSA 2017.

Abstract
A long-period grating (LPG) written on a standard single mode fiber is investigated as a fiber optic sensor for vibration and magnetic field sensing. It is demonstrated the high sensitivity of the device to applied curvature and the possibility to monitor vibration in a wide range of frequencies from 30 Hz to 2000 Hz. The system was tested using intensity-based interrogation scheme, providing a frequency discrimination of 913 mHz. The goal of these tests was to evaluate the sensor as a passive vibration monitor in the detection of changes in resonant vibration frequencies of support infrastructures can provide information on its degradation. Furthermore, taking advantage of the intrinsic sensitivity to micro strain, alternating magnetic fields were also measured using an intensity-based interrogation scheme by coupling a Terfenol-D magnetostrictive rod to a pre-strained LPG sensor, providing a resolution below 5.61 mu T-rms/root Hz from 1.22 mT(rms) up to 2.53 mT(rms).

Abstract
A metrological assessment of grating-based optical fiber sensors is proposed with the aim of providing an objective evaluation of the performance of this sensor category. Attention was focused on the most common parameters, used to describe the performance of both optical refractometers and biosensors, which encompassed sensitivity, with a distinction between volume or bulk sensitivity and surface sensitivity, resolution, response time, limit of detection, specificity (or selectivity), reusability (or regenerability) and some other parameters of generic interest, such as measurement uncertainty, accuracy, precision, stability, drift, repeatability and reproducibility. Clearly, the concepts discussed here can also be applied to any resonance-based sensor, thus providing the basis for an easier and direct performance comparison of a great number of sensors published in the literature up to now. In addition, common mistakes present in the literature made for the evaluation of sensor performance are highlighted, and lastly a uniform performance assessment is discussed and provided. Finally, some design strategies will be proposed to develop a grating-based optical fiber sensing scheme with improved performance.

Abstract
The development of economical optical devices with a reduced footprint foreseeing manipulation, sorting and detection of single cells and other micro particles have been encouraged by cellular biology requirements. Nonetheless, researchers are still ambitious for advances in this field. This paper presents Fresnel zone and phase plates fabricated on mode expanded optical fibres for optical trapping. The diffractive structures were fabricated using focused ion beam milling. The zone plates presented in this work have focal distance of similar to 5 mu m, while the focal distance of the phase plates is similar to 10 mu m. The phase plates are implemented in an optical trapping configuration, and 2D manipulation and detection of 8 mu m PMMA beads and yeast cells is reported. This enables new applications for optical trapping setups based on diffractive optical elements on optical fibre tips, where feedback systems can be integrated to automatically detect, manipulate and sort cells.