91results about How to "Reduce attenuation" patented technology

Support devices and pods for the head and neck region of patients undergoing radiation therapy are provided herein. The pod generally includes a support shell shaped to generally conform to the shape of the head and neck region of the patient, a foam insert that conforms to the head and neck region of the patient, and an immobilization facemask attached directly to the shell, thereby facilitating close placement of the radiation beam delivery device to the patient and reducing any attenuation and perturbation of radiation doses directed at the patient. The components of the pod are made from materials having properties that reduce any attenuation and perturbation of prescribed radiation doses.

The present invention relates to a high-bandwidth bending-insensitive multimode optical fiber. The optical fiber comprises a core layer and a cladding layer, wherein the cladding layer includes an inner cladding layer, a depressed cladding layer and an outer cladding layer which are distributed from inside to outside. The optical fiber is characterized in that the refractive index profile of the core layer is of a parabola shape; the distribution index alpha of the core layer ranges from 2.0 to 2.3; the radius R1 of the core layer ranges from 23 to 27 micrometers; the maximal relative refractive index difference delta1max of the center of the core layer ranges from 0.9% to 1.2%; the core layer is a germanium (G), phosphorus (P) and fluorine (F) co-doped silica glass layer; the contributionamount deltaP0 of phosphorus (P) at the center of the core layer ranges from 0.01% to 0.30%; the contribution amount deltaP1 of phosphorus (P) at the interface of the core layer and the inner cladding layer ranges from 0.01% to 0.30%; the content of phosphorus (P) at the center of the cover layer is consistent with the content of phosphorus (P) at the edge of the core layer; the doping amount offluorine (F) is gradually increased from the center of the core layer to the edge of the core layer; the contribution amount deltaF0 of fluorine (F) at the center of the core layer ranges from 0.0% to-0.1%; and the contribution amount deltaF1 of fluorine (F) at the edge of the core layer ranges from -0.4% to -0.20%;. The material compositions of the high-bandwidth bending-insensitive multimode optical fiber and the structural design of the core layer and cladding layer of the high-bandwidth bending-insensitive multimode optical fiber are reasonable; the chromatic dispersion of the optical fiber is reduced; the bandwidth performance of the optical fiber is improved; and the attenuation of the optical fiber is reduced.

A core part of a multimode optical fiber including the core part and a cladding part has a structure composed of a plurality of concentric layers in which a refractive index is decreased stepwise from a first core layer as an innermost layer to a third core layer as an outermost layer. The structure having the plurality of layers is formed by adjusting a quantity of addition of fluorine to silica glass. Fluorine is added to the cladding part so that a refractive index is lower than that of the third core layer as the outermost layer of the core part.

The waveguide structure of single-mode optical fibre comprises layered fibre core and layered clad. The fibre core is set with two core layers in different refractive indexed and layered clad consists of five layered clads. The codeposition of fluorine and germanium is applied by utilizing PCVD process to replace independent deposition of fluorine or germanium in deposition process for fibre core and clad so optical, mechanical and environmental performance of optical fibre is very much improved. The single-mode optical fibre produced in the present invention can be used in transmission of DWDM system.