A MULTI-MODE OPTICAL FIBER FOR ACHIEVING AN OPTICAL ATTENUATION TO A DESIRED DEGREE AT SPECIFIC WORKING WAVELENGTHS OR ACHIEVING A SUBSTANTIALLY UNIFORM OPTICAL ATTENUATION IN SPECIFIC RANGE OF WAVELENGTH

摘要

A multi-mode optical fiber for securing desirable optical attenuation at specific working wavelengths or substantially uniform optical attenuation in a specific wavelength band is provided to keep an input optical signal uniform by co-doping a core part with first and second metallic ions having respective light absorption coefficients of the negative and positive gradients in an optical signal wavelength band. A multi-mode optical fiber for securing desirable optical attenuation at specific working wavelengths has a core layer(13) and a cladding layer(12). The thickness ratio of the core layer and the cladding layer is 50nm:125nm or 62.5nm:125nm. The core layer is doped with at least one ion of a first metal having a light absorption coefficient of the negative gradient in the specific working wavelength.