Abstract
A study of long period fiber gratings (LPFG) over coated with iron (Fe) and subjected to oxidation in water with different sodium chloride (NaCl) concentrations is presented. The formation of iron oxides and hydroxides was monitored in real time by following the features of the LPFG attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

Abstract
In this work an investigation of long period fiber gratings (LPFGs) over coated with iron (Fe) thin layers with different thicknesses and subjected to oxidation in air atmosphere under controlled temperature is presented. The formation of iron oxides was monitored in real time by following the optical features of the LPFG attenuation band. The morphology of the oxide layer was further analyzed by scanning electron microscope (SEM). Preliminary results show that iron coated LPFGs can be used as sensors for early warning of corrosion in projects where metal structures made of iron alloys are in contact with atmospheric air.

Abstract
This work reports the theoretical investigation of optical fiber surface plasmon resonance sensors incorporating bimetallic layer combinations. Different metals like silver, gold, copper, and aluminum are considered to investigate the refractometric sensing properties of tapered and tip optrode phase-interrogated optical fiber plasmonic sensor structures. It is shown that the gold-silver combination, coupled to a tip optrode layout, is capable of maximizing the resolution and operation range of these sensing structures for environmental refractive index measurement.

Abstract
Long period fiber gratings (LPFGs) were over coated with iron (Fe) and subjected to oxidation in air and in solutions of water containing different sodium chloride (NaCl) concentrations. The formation of iron oxides and hydroxides was monitored in real time by following the features of the gratings attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

Abstract
The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments.

Abstract
A Fabry-Perot interferometer based on an array of soda-lime glass microspheres is proposed for temperature sensing. The microspheres are introduced in a hollow-core silica tube using a tapered fiber tip. After the insertion of each microsphere the sensor is subjected to temperature measurements. The sensor exhibits non-linear behavior and a dependence on the number of microspheres is observed. A maximum sensitivity of 11.13 pm/degrees C is achieved, when there is only one microsphere inside the capillary structure.