Abstract: An optical fiber includes: a core (1) having an outer diameter (D1) of greater than or equal to 8.2 ?m and less than or equal to 10.2 ?m; a first cladding (2) surrounding the core (1) and having an outer diameter (D2) of greater than or equal to 30 ?m and less than or equal to 45 ?m; a second cladding (3) surrounding the first cladding (2) and having a thickness (T) of greater than or equal to 7.4 ?m; and a support layer (4) surrounding the second cladding (3). The relative refractive index difference which is the ratio of the difference between the refractive index of the support layer (4) and that of the second cladding (3) to the refractive index of the support layer (4) is greater than or equal to 0.5%.

Abstract: An optical fiber includes: a core (1) having an outer diameter (D1) of greater than or equal to 8.2 ?m and less than or equal to 10.2 ?m; a first cladding (2) surrounding the core (1) and having an outer diameter (D2) of greater than or equal to 30 ?m and less than or equal to 45 ?m; a second cladding (3) surrounding the first cladding (2) and having a thickness (T) of greater than or equal to 7.4 ?m; and a support layer (4) surrounding the second cladding (3). The relative refractive index difference which is the ratio of the difference between the refractive index of the support layer (4) and that of the second cladding (3) to the refractive index of the support layer (4) is greater than or equal to 0.5%.

Abstract: It is to provide a method for laminating a woody fiberboard in which woody fiberboards are laminated with increasing the strength thereof, the laminated woody fiberboard is processed into a prescribed shape and the strength of the processed article is increased, so as to complete the product. The method comprises the steps of: molding wood chips using an adhesive as a binder, to produce a woody fiberboard having a prescribed thickness; impregnating or coating a single board of the woody fiber board with a polyurethane series primer, followed by drying; laminating by adhering two or more of the dried woody fiberboards with adhesive; processing the laminated woody fiberboard by a cutting blade into a prescribed shape; impregnating or coating the processed article with a polyurethane series primer followed by drying; and impregnating or coating the dried article with one or more of a urethane series resin, a melamine series resin, a polyester series resin and a lacquer, so as to finish the product.