| 摘要 |
<p>To be provided is an amplifying optical fiber allowing for efficient absorption of pumping light by an active element therein, and an optical fiber amplifier using the amplifying optical fiber. An amplifying optical fiber (20) includes a core (21) doped with an active element, a cladding (22) covering the core (21), and an outer cladding (23) covering the cladding (22). The cladding (22) meets a relationship of 0.92 ‰¤ r/R ‰¤ 0.97 where the cladding (22) has a polygonal outer shape in cross section, and the outer shape has an inscribed circle of a diameter r and a circumscribed circle of a diameter R.</p> |
