There is a large interest in using high power lasers for surface alloying or cladding on aluminium alloys, in order to enhance hardness and to improve wear resistance. A partly quasicrystalline surface layer (QC) (Al-Cu-Fe coating) has been obtained by laser cladding on Al-base materials. In addition to crystalline phases (Al5Fe2 and AlisFe4t -with dissolved copper), a quasicrystalline Al-Cu-Fe...

We developed an asymptotic formalism that fully characterizes the propagation and loss properties of a Bragg fiber with finite cladding layers. The formalism is subsequently applied to miniature air-core Bragg fibers with Silicon-based cladding mirrors. The fiber performance is analyzed as a function of the Bragg cladding geometries, the core radius and the material absorption. The problems of ...

We study the applicability of the weakly guiding approximation (WGA) to the modal analysis of an M-type optical fiber in which a ring-shaped core lies between two uniform cladding layers. Besides being dependent on the refractive indices, the accuracy of the approximation is shown to be substantially affected by the transverse dimensions of the core. The accuracy is characterized by calculating...

A long-period grating (LPG) based compact optical fiber sensor working in reflection mode is demonstrated. A technique to make a mirror on the cladding region of a fiber end-face to reflect only the cladding modes was realized by growing a polymeric microtip on the core region of the fiber end-face, by photopolymerization, followed by coating the fiber end-face with an aluminum film. Using the ...

Using the beam propagation method, an analytical expression of the reflection spectra of a Kretschmann configuration is derived in order to excite hybridized surface plasmonic polaritons (HSPPs). In this configuration, the cladding is a uniaxial dielectric with the optical axis parallel to the interface. The validity of the analytical expression is confirmed by a finite-difference time-domain a...

Confinement loss is comprehensively evaluated for TE, TM, and hybrid modes of Bragg fibers using a multilayer division method newly developed. We show the loss dependence on the core radius, wavelength, cladding index contrast, and the number of cladding pairs. The confinement loss is reduced in proportion to (a/b)(2N) and (n(2) (b)b/n(2) (a)a)(2N) for the TE and other three modes, respectively...

A highly porous optical-fiber cladding was developed for evanescent-wave fiber sensors, which contains sensor molecules, maintains guiding conditions in the optical fiber, and is suitable for sensing in aqueous environments. To make the cladding material (a poly(ethylene) glycol diacrylate (PEGDA) polymer) highly porous, a microsphere templating strategy was employed. The resulting pore network...

In laser cladding, a material, usually in the form of powder, is deposited on a substrate. Powder particles are intermingled with inert gas and fed by a powder feeder system on the substrate. Laser is employed to melt the additive material and a small layer of surface of the substrate simultaneously. While the powder is being deposited, the laser melts the powder particles and the melted powder...