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AssigneeUniversity of Southampton
InventorsNeil Gregory Raphael Broderick, Peter Jonathan Bennett, Tanya Mary Monro, David John Richardson
Estimating the term…
The percentage fraction of fundamental mode power located in the cladding holes of different holey fibers (PFholes) is shown as a function of wavelength in microns of the fundamental mode (λ). Properties of two groups of holey fibers are shown. The upper group of three curves shows embodiments of the invention with Λ=0.75 μm and d/Λ=0.6, 0.7 & 0.8 respectively, where d is the hole diameter and Λ the hole spacing or pitch. The lower group of curves, which are almost superimposed on each other, show properties of holey fibers representative of the prior art with Λ=3.2 μm and d/Λ=0.6, 0.7 & 0.8 respectively. A huge improvement in the mode power present in the holes is evident. In the prior art curves, the mode power fraction is generally less than 1%, whereas with the illustrated embodiments of the invention, holey fibers with 10-40% of the fundamental mode power in the holes are achieved. Generally the holey fiber should be structured such that the wavelength of the guided light λ>2.2Λ. For telecommunications wavelengths, this means that the hole spacing should be smaller than typical in the prior art, i.e. around 1 μm or less, and the hole diameter should be as large as possible in relation to the hole spacing, preferably d/Λ>=0.6.
An optical fiber having a core and a cladding, the cladding containing holes defined by cavities that run lengthwise down the optical fiber and that are distributed across the optical fiber adjacent to the core to define a pitch, wherein the pitch is between 0.1 and 0.9 microns, wherein the holes have a characteristic hole size and the ratio of hole size to pitch is greater than or equal to approximately 0.6.
A method of guiding light along an optical fiber by average refractive index effects, the optical fiber having a core and a cladding, the cladding containing holes defined by cavities that run lengthwise down the optical fiber and that are distributed across the optical fiber to define a pitch of between 0.1 and 0.9 microns, wherein the wavelength of the light is at least approximately 2.2 times the pitch of the holes, and wherein the holes have a characteristic hole size and the ratio of hole size to pitch is greater than or equal to approximately 0.6.
Dependencies are inferred from the claim text.