Large mode area optical fiber

摘要

A large-mode-area (LMA) optical fiber (10) that operates as a single-mode optical fiber. The optical fiber includes a core region (20) surrounded by an inner cladding (32), which in turn is surrounded by an outer cladding (40). The inner cladding includes at least one up-doped ring region (32R1). The ring region is configured to form a large attenuation differential between the higher-order modes and the fundamental mode so only that the fundamental mode remains traveling in the optical fiber. If necessary, the optical fiber can include a bend (10B) having a select “resonant” bend diameter (DB) that increases the relative attenuation of the fundamental and higher-order modes. The optical fiber supports an effective mode field diameter (MFD) of up to 40 μm to 50 μm. As a result, detrimental non-linear effects are suppressed, which allows the optical fiber to carry substantially more optical power than conventional LMA optical fibers. The LMA optical fiber is thus eminently suited for a number of optical-fiber-based applications calling for high optical power, such as fiber lasers and pump sources for wavelength conversion.

主权项

1. A large-mode-area (LMA) optical fiber comprising:
(i) a core region having a relative refractive index ΔC wherein 0.02%<ΔC<0.15% and core radius r1 wherein 10 μm(a) a first annular region immediately adjacent to and surrounding the core region and having an inner radius r1, an outer radius r2=r1+δr1, where 3 μm<δr1<15 μm, and a relative refractive index Δ1=0%;(b) at least a first ring surrounding said first annular region and having a relative refractive index ΔR1 wherein 0.5ΔC<ΔRI<2ΔC, and ΔRI>ΔI, an inner radius r2, an outer radius r3, and a ring width WRI, wherein rIN=r3+ΔrO1 for δrO1≧0, and wherein rIN≧r3>r2>r1; (iii) an annular outer section immediately surrounding the ring section and having an inner radius r3, an outer radius rIN=r3+ΔrO, and a relative refractive index Δ3, wherein Δ3≧Δ1; and (iv) an outer cladding immediately surrounding the inner cladding and having a relative refractive index ΔO≦Δ1.