Abstract
Colorectal carcinoma is a major health concern worldwide and its high incidence and mortality require accurate screening methods. Following endoscopic examination, polyps must be removed for histopathological characterization. Aiming to contribute to the improvement of current endoscopy methods of colorectal carcinoma screening or even for future development of laser treatment procedures, we studied the diffusion properties of glucose and water in colorectal healthy and pathological mucosa. These parameters characterize the tissue dehydration and the refractive index matching mechanisms of optical clearing (OC). We used ex vivo tissues to measure the collimated transmittance spectra and thickness during treatments with OC solutions containing glucose in different concentrations. These time dependencies allowed for estimating the diffusion time and diffusion coefficient values of glucose and water in both types of tissues. The measured diffusion times for glucose in healthy and pathological mucosa samples were 299.2 +/- 4.7 s and 320.6 +/- 10.6 s for 40% and 35% glucose concentrations, respectively. Such a difference indicates a slower glucose diffusion in cancer tissues, which originate from their ability to trap far more glucose than healthy tissues. We have also found a higher free water content in cancerous tissue that is estimated as 64.4% instead of 59.4% for healthy mucosa. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

Abstract
1xN (N=2, 3, 4) MMI power splitters were fabricated in a fused silica substrate by laser direct writing, using a focused 515 nm amplified femtosecond laser beam, and characterized at 1550 nm. To accomplish this, several low loss waveguides were fabricated side by side to form a multimode waveguide with the output in a polished facet of the substrate, while a single low loss waveguide was fabricated to inject light in the centre of the multimode waveguide. The performance of the fabricated devices was optimized by testing three different designs.

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.

Abstract
Long period fiber gratings (LPFGs) were used to monitor the characteristics of copper (Cu) thin films when annealed in air atmosphere up to similar to 680 degrees C. The wavelength and the optical power shift of the resonant bands of the LPFGs when coated with the Cu thin films, were measured as a function of the annealing temperature, and were found to exhibit a different evolution comparing to a bare LPFGs. Thin films of Cu deposited on quartz (SiO2) substrates were annealed and analyzed by XRD, SEM/EDS and Raman spectroscopy, allowing to identify the formation of two distinct oxide phases at different temperatures, cuprous (Cu2O-cuprite) and cupric (CuO-tenorite) oxides, respectively. The observed features of the resonant bands of the LPFGs were found to be associated with the Cu oxide phase transitions, indicating the possibility of using LPFGs to monitor, in real time, the oxidation states of Cu thin films by following specific characteristics of the attenuation bands. In addition, LPFGs over coated with the two distinct oxidation phases of Cu were characterized for refractive index sensing in the range between 1.300 to 1.600, leading to the conclusion that the sensitivity to the refractive index of the surrounding medium of Cu coated LPFGs sensing systems can be temperature tuned.

Abstract
The proposed technique consists in an optical fiber resonator interrogated for sensor characterization, implementing an alternative technique for dynamic range improvement. Such technique relies on the analysis of an added-signal caused by signal saturation, which occurs due to the broadening of the laser pulse. A wide study for different pulse widths is presented in this work, namely for 100 ns, 5 mu s and 20 mu s, being the last one related to the emergence of an added-signal for the proposed configuration. The behavior of the waveform in the presence of an intensity sensor is also characterized.

Abstract
The fabrication of optical add-drop multiplexers in fused silica is demonstrated, for the first time to our knowledge, using the femtosecond laser direct writing technique. To achieve this, a Mach-Zehnder interferometer configuration was used for the signal routing by the implementation of 3-dB directional couplers, along with Bragg grating waveguides for wavelength selectivity. The fabrication of all individual devices required was optimized. The behavior of the fabricated add-drop multiplexer was characterized at around 1550 nm, where a 3-dB bandwidth of 0.19 +/- 0.01 nm was obtained along with an intrachannel and adjacent interchannel crosstalk of -30 and -20 dB at Delta lambda = +/- 0.75 nm, respectively. This study shows that such complex devices can be manufactured by femtosecond laser direct writing, with future improvements being discussed.