MICROSTRUCTURED OPTICAL FIBRE HAVING A LARGE CORE AND A FLATTENED FUNDAMENTAL MODE, PRODUCTION METHOD THEREOF AND USE OF SAME IN LASER MICROFABRICATION

摘要

The fiber comprises a core (2) having an index N and diameter of 10μm or more, surrounded by a ring (4) having an index N+Δn and thicknessΔR, and cladding (6) surrounding the ring and comprising for example air gaps (8). According to the invention:Δn≧10−3 andΔR=α/(Δn)β[1] where: 5×10−4μm≰α≰5×10−2μm and 0.5≰β≰1.5. The numbersαandβare dependent on the wavelengthλof the light guided by the fiber, the number of missing gaps therein, the diameter d of the gaps, the spacingΛthereof and N. To design the fiber,λ, the number of missing gaps, d/Λ, the core doping content,ΛandΔn are chosen; andΔR is determined using equation [1] so as to obtain a flattened fundamental mode.