Patent ID: 9366806
Filing Date: 2016-06-14
CPC Classification: C03B,G02B,H01S

Claim Text:
1. A gain-producing optical fiber comprising: a core region having a longitudinal axis, a cladding region surrounding said core region, said core and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in the direction of said axis, said cladding region including a trench region surrounding said core region, an inner cladding region surrounding said trench region, and an outer cladding region surrounding said inner cladding region, said inner cladding region having a refractive index less than that of said core region, and said trench region having a refractive index below that of said inner cladding region, at least said core region including at least one gain-producing species that provides gain to said signal light when suitable pumping energy is applied to said fiber, and said core and cladding regions being configured so that said fundamental mode is guided predominantly in said core region and the difference in refractive index Δn wherein said core, trench and inner cladding regions are configured to increase by at least approximately 30% the cladding absorption (α