Optical fiber with specialized figure-of-merit and applications therefor
AssigneeOFS Fitel, LLC
InventorsPoul Kristensen, Philip G Westergaard
Life of this patent
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Abstract
A specialized, dispersion-controlled fiber is particularly configured to exhibit a relatively uniform dispersion (D) over a broad spectral range (for example, 1000 nm to 2000 nm). The specialized fiber exhibits an essentially constant attenuation (α) over this same spectral range so that the fiber is defined as having a high “figure of merit” (FoM) where FoM is defined as |D|/α. The specialized fiber is well-suited for use as a pulse stretcher, providing the ability to separate out wavelength constituents of an extremely short (fs, ps) broadband pulse into the ns range, for example.
Claims8
An optical fiber comprising
- a core region including
- an up-doped central core area having a diameter in the range of 2-4 μm;
- a down-doped trench surrounding the up-doped central core area and having a diameter in the range of 5-9 μm, where the change in refractive index Δn1 between the up-doped central core area and the down-doped trench has a value of at least 0.020;
- and
- an outer core region surrounding the down-doped trench and having a thickness of about 4 μm such that the complete core region exhibits a diameter in the range of 9-13 μm, the outer core region having a refractive index value greater than the down-doped trench with a Δn2 between the trench and the outer core region being in the range of about 0.005-0.015, the combination of Δn1, Δn2, diameters of the up-doped central core area and the down-doped trench and thickness of the outer core region creating a uniform chromatic dispersion D of a value greater than 50 ps/nm/km over a spectral range of 1000-2000 nm;
- a cladding region surrounding the core region and including
- an inner cladding layer having a first refractive index value;
- and
- an outer cladding layer surrounding the inner cladding layer and having a second refractive index value greater than the first refractive index value;
- and
- a coating layer surrounding the cladding region, where the thicknesses of each region and their respective index values are selected to form an optical fiber exhibiting a relatively high and uniform figure-of-merit (FoM) over a broad spectral range, where FoM is defined as:
- FoM=|D|/α,
- where |D| is an absolute value of the chromatic dispersion in a propagating optical signal and α is attenuation of the propagating optical signal, both |D| and a measured as a function of wavelength.
Dependencies are inferred from the claim text.