Long Period Gratings in Random Hole Optical Fibers for Refractive Index Sensing

Long Period Gratings in Random Hole Optical Fibers for Refractive Index Sensing

We have demonstrated the fabrication of long period gratings in random hole optical fibers. The long period gratings are fabricated by a point-by-point technique using a CO(2) laser. The gratings with a periodicity of 450 μm are fabricated and a maximum coupling efficiency of -9.81 dB has been achieved. Sensing of different refractive indices in the surrounding mediums is demonstrated by applyi...

Sensing Features of Long Period Gratings in Hollow Core Fibers

We report on the investigation of the sensing features of the Long-Period fiber Gratings (LPGs) fabricated in hollow core photonic crystal fibers (HC-PCFs) by the pressure assisted Electric Arc Discharge (EAD) technique. In particular, the characterization of the LPG in terms of shift in resonant wavelengths and changes in attenuation band depth to the environmental parameters: strain, temperat...

Pressure Sensing in High-Refractive-Index Liquids Using Long-Period Gratings Nanocoated with Silicon Nitride

The paper presents a novel pressure sensor based on a silicon nitride (SiNx) nanocoated long-period grating (LPG). The high-temperature, radio-frequency plasma-enhanced chemical-vapor-deposited (RF PECVD) SiNx nanocoating was applied to tune the sensitivity of the LPG to the external refractive index. The technique allows for deposition of good quality, hard and wear-resistant nanofilms as requ...

Long Period Gratings in New Generation Optical Fibers

Long period gratings in multimode optical fibers: application in chemical sensing

We propose and demonstrate a new technique for evanescent wave chemical sensing by writing long period ~ in a bare multimode plastic clad silica tiber. The sensing length of the present sensor is only IQ mm, but is as sensi1iIt; a conventional unclad evanescent wave sensor having about 100 mm sensing length. The minimum measurabkl1! centratioll of the sensor reported here is 10 nmoUl and the op...