Abstract: Disclosed is a fiber optic module containing one or more optical fibers having an attenuator formed in the output end of the fibers to filter out unwanted higher order modes. The optical fibers are typically gain fibers or dispersion compensating fibers, and the attenuator consists of a coil, or a series of bends, of sufficient number and bend radius that higher order modes are reduced below a desired level.

Abstract: An optical waveguide fiber amplifier comprising a core region comprises at least in part between 1300 wt.ppm and 3600 wt.ppm Er2O3, between 6.0 wt. % to 10.0 wt. % Al2O3 and between 9.0 wt. % and 20.0 wt. % GeO2. The amplifier also comprising an inner clad surrounding the core region and an outer clad surrounding the inner clad. The relative refractive index percentages and radii of the core region, inner clad and outer clad are chosen from the following ranges: the relative refractive index percent of the core segment within the range of from about 0.5% to about 2.0%; the relative refractive index percent of the inner clad within the range of from about 0.0% to about 0.4%; the outer radius of the core region within the range of from about 0.7 &mgr;m to about 1.5 &mgr;m; and, the outer radius of the inner clad within the range of from about 4.3 &mgr;m to about 18.8 &mgr;m.

Abstract: Disclosed is a fiber optic module containing one or more optical fibers having an attenuator formed in the output end of the fibers to filter out unwanted higher order modes. The optical fibers are typically gain fibers or dispersion compensating fibers, and the attenuator consists of a coil, or a series of bends, of sufficient number and bend radius that higher order modes are reduced below a desired level.

Abstract: An optical waveguide fiber amplifier comprising a core region comprises at least in part between 1300 wt.ppm and 3600 wt.ppm Er2O3, between 6.0 wt. % to 10.0 wt. % Al2O3 and between 9.0 wt. % and 20.0 wt. % GeO2. The amplifier also comprising an inner clad surrounding the core region and an outer clad surrounding the inner clad. The relative refractive index percentages and radii of the core region, inner clad and outer clad are chosen from the following ranges: the relative refractive index percent of the core segment within the range of from about 0.5% to about 2.0%; the relative refractive index percent of the inner clad within the range of from about 0.0% to about 0.4%; the outer radius of the core region within the range of from about 0.7 &mgr;m to about 1.5 &mgr;m; and, the outer radius of the inner clad within the range of from about 4.3 &mgr;m to about 18.8 &mgr;m.