A Study on Material Dispersion around Zero Material Dispersion Wavelength of Different Material Composition based Optical Fiber

The Optical Fiber-based communication system has established its proficiency and inevitability towards regular progress and advancement worldwide. The most attractive wavelength for optical fiber communication is 1.55 μm, as it represents the lowest loss. The other challenging parameter ‘Material Dispersion’ gets reduced to ‘Zero’ at 1.27 μm wavelengths for conventional pure silica-based Optical Fiber. To improve the system towards a better unification between the loss and dispersion, the Dispersion Shifted Fiber (DSF) has been introduced. The Dispersion Flattened Fiber has introduced the concept of flat dispersion over a wide range of wavelengths. But the effective combination of the mechanisms to compensate for all the challenges is yet to be established properly. The said mechanisms are complex to design and implement. So, there is an immense scope to search for an alternative to get control over the loss and dispersion. At present, a fair number of material compositions of optical fiber are reported with different specifications. Our study on some of these fiber compositions has produced some interesting data towards the broader flatness and the minimum dispersion effect over a considerable range of wavelengths around the Zero Material Dispersion Wavelength (ZMDW). It helps to have more effective wavelength division Multiplexing (WDM). In this paper, we have studied different prospective options of optical fiber doping profiles to explore and propose an effective and optimized alternative among the available fiber profiles. We have studied the samples of pure SiO2 fibers along with B2O3 and GeO2 doped fibers and samples of Fluoride-based ABCY and ZBLAN glass Fibers to propose an effective combination of materials among the available options to get the optimized conjugation of loss and dispersion. Our report on the comparative study of different fiber materials has produced some effective results to have minimum material dispersion at the lowest loss wavelength to invite worldwide attention from system designers.

Non-removable butt joints of an aluminum-matrix composite material dispersion-hardened by particles of SiC, made by friction stir welding

Friction stir welding of butt joints of aluminum-matrix dispersion-strengthened composite materials is considered. It is shown that with an increase in the content of strengthening SiC particles, the range of welding modes that ensure the formation of a joint without defects is significantly narrowed. It was found that under cyclic loads, welded joints begin to fail from the face of the weld. Keywords: friction stir welding, aluminum matrix dispersion-hardened composite material, mode, structure, roughness, strength. [email protected]

Dispersion mechanism and characterization of wood pulp-based wetlaid/spunlace materials

Wood pulp-based wetlaid/spunlace (wetlace) materials had an in-use dry or wet strength, but relatively quickly breakdown in municipal sanitization systems without block, such as sewer or septic systems. In order to further study the mechanism and characterization of material dispersion process, the relationship between dispersion time and sample residual rate or dispersion rate was analyzed on the basis of previous research methods. Meanwhile, the crowding factor was introduced for evaluation and the material dispersion mechanism was comprehensively expounded. The dispersion properties of wood pulp-based wetlace materials with different Danufil length-to-diameter (L/D) ratios and contents could be clearly distinguished at the stirring rate of 220 rpm. Meanwhile, the crowding factor was between 14 and 60 when wetlace materials reached dispersion balance, and the increase in crowding factor of wood pulp/Danufil-water dispersion system resulted in increasing the required dispersion time. Overall, the dispersion process could be divided into four stages: stable state of relative dispersion rate (low level), rapid ascent phase, fast descent stage, and constant region again (high level).

Nonlinear Optical Fibers, Their Properties, and Applications

Nonlinear optical properties and preparation of nonlinear optical fiber based on Bismuth oxide were described. Wavelength dependence of refractive index of ABH160 and B027 was studied and analyzed. Working and construction of optical ON-OFF switches, based on Bi-HNLF was reported. It was investigated that refractive index of ABH160 and Bo27 were found to be exponentially decaying as a function of wavelength. Absorption coefficient of ABH160 as a function of wavelength was found to be decaying exponentially. In optical fiber the total group velocity dispersion is divided into the material dispersion DM and waveguide dispersion DW. Material dispersion and waveguide dispersion were calculated theoretically and a good agreement with the experimental result. The process of four wave mixing and consequences was reviewed.