Analysis of Optical Properties for Square, Circular and Hexagonal Photonic Crystal Fiber

This paper presents four rings square, circular, and hexagonal photonic crystal fiber (PCF) geometry for analyzing different optical properties in a wavelength ranging from 800 nm to 1600 nm. These three types of geometry have been used for analyzing Effective area, Propagation constant, Confinement loss and Waveguide dispersion. Silica glass is chosen as background material and the cladding region is made of four air hole layers. COMSOL Multiphysics (v.5) software is used to simulate these proposed PCF geometries. From the numerical analysis, it is found that the effective area is small for hexagonal PCF geometry and large for square PCF geometry (11.827 μm2, 10.588 μm2 and 9.405 μm2 for square, circular, and hexagonal PCF geometry respectively). From the analysis, the Confinement loss is approximately zero at wavelength ranges from 800 nm to 1250 nm and approximately zero waveguide dispersion is achieved from 900 nm to 1500 nm for all the three PCF structures. Again, negative dispersion approximately −30.354 ps/(nm⋅km) is achieved for circular PCF structure at the wavelength of 900 nm.

Interaction Properties of Geosynthetic with Different Backfill Soils

Characterization of a geosynthetic is necessary for its effective use in various field application of reinforced soil structure. In this paper, a new type of geosynthetic has been evaluated for its interaction properties for different backfill soils using direct shear device. The test results are compared based on the type of soils, inclusions, and interface mechanical properties. Three backfills soils (sandy, clayey, and pure sand) in combination with four different geosynthetics (one geotextile and three geogrids) were tested at various loading conditions in direct shear. Test results reveal that the stress-deformation behaviour of the geotextile and geogrid interfaces with sandy and clayey backfills can be defined as hyperbolic. For the pure sand-geogrid interfaces, the relationship is followed by displacement hardening and softening behaviour. The dilatancy behaviour of a particular soil-geosynthetic interface is found similar at all normal stresses. Both contractive and dilative nature is observed for the interfaces with pure sand. On the contrary, only negative dilatancy or contractive behaviour is observed for sandy and clayey backfills with the same geosynthetics. The test results reveal that the relationship of the interface shear strength with the normal stress is not linear in most cases. Based on the test results, a simplified nonlinear equation is proposed for the soil-geosynthetic interface shear strength envelops which was in good agreement with the experimental data.

Alcohol Sensing through Photonic Crystal Fiber at Different Temperature

This paper presents the investigation of relative sensitivity profile of Alcohol through Photonic Crystal fiber at different temperature. Here, 15%, 40%, 60%, 75% of Ethyl Alcohol-water mixture is inserted through the core of Photonic crystal fiber at temperature like 20°C, 25°C and 30°C. COMSOL Multiphysics is used as simulation software and the simulation process is done at wavelength range 600 nm to 1600 nm. From this work, the relative sensitivity is obtained approximately 44, 44.59, 44.85, 45 in percentage at temperature 20°C, 42, 44.2, 44.8, 44.9 in percentage at temperature 25°C, and 42, 43.8, 44.5, 44.85 in percentage at temperature 30°C for 15%, 40%, 60%, 75% of Ethyl Alcohol-water mixture at wavelength 1500 nm respectively. Again, higher sensitivity is achieved when this sensor is operated at lower temperature.