Photonic bandgap fibers
AssigneeImra America, Inc.
InventorsLiang Dong, Xiang Peng
Life of this patent
Estimating the term…
Abstract
Included among the many structures described herein are photonic bandgap fibers designed to provide a desired dispersion spectrum. Additionally, designs for achieving wide transmission bands and lower transmission loss are also discussed. For example, in some fiber designs, smaller dimensions of high index material in the cladding and large core size provide small flat dispersion over a wide spectral range. In other examples, the thickness of the high index ring-shaped region closest to the core has sufficiently large dimensions to provide negative dispersion or zero dispersion at a desired wavelength. Additionally, low index cladding features distributed along concentric rings or circles may be used for achieving wide bandgaps.
Claims27
A photonic bandgap fiber for propagating light having a wavelength, λ, comprising:
- a core;
- and
- a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl, said first plurality of high index ring-shaped regions having an average thickness, d, and an average periodicity, Λ, such that the ratio d/Λ is less than about 0.3,
- wherein said cladding has a normalized frequency ν=2πd(nh2−nl2)1/2/λ that is less than about π radians and said core has a wavelength transmission band larger than about 100 nm.
A photonic bandgap fiber for propagating light having a wavelength, λ, comprising:
- a core;
- and
- a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl, said first plurality of high index ring-shaped regions having an average thickness, d,
- wherein said high index ring-shaped region closest to said core forms a core cladding boundary has an average thickness, δ, so as to provide a normalized frequency ν=2πδ(nh2−nl2)1/2/λ that is less than about 1 radian.
A photonic bandgap fiber having a transmission band comprising:
- a core larger than about 10 μm;
- and
- a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl, said first plurality of high index ring-shaped regions having an average thickness, d, and an average periodicity, Λ, such that the ratio d/Λ is less than about 0.2,
- wherein said fiber has a dispersion between about −50 to 50 ps/nm/km over at least about 100 nm of said transmission band.
A photonic bandgap fiber having a transmission band comprising:
- a core;
- and
- a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl, said first plurality of high index ring-shaped regions having an average thickness, d, and an average periodicity, Λ, such that the ratio d/Λ is less than about 0.2, said high index ring-shaped region closest to said core having a thickness, δ, larger than about 1.1 times the average thickness, d,
- wherein said fiber has a dispersion below about −50 ps/nm/km over at least about 20 nm of the transmission band.
A photonic bandgap fiber for propagating light having a wavelength, λ, comprising:
- a core;
- and
- a cladding disposed about said core, said cladding comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl,
- wherein said high index ring-shaped region has an average thickness, d, such that the fiber has a transmission loss of less than about 100 dB/km at a wavelength corresponding to a normalized frequency ν=2πd(nh2−nl2)1/2/λ between about (a) 0.55π to 0.85π, (b) 1.05π to 1.75π, or (c) 2.4π to 2.7π.
A photonic bandgap fiber having a transmission band comprising:
- a core;
- and
- a cladding disposed about said core comprising a first plurality of ring-shaped regions defined by high index material having an index of refraction, nh, and a second plurality of ring-shaped regions having a low index of refraction, nl, said first plurality of high index ring-shaped regions having an average thickness, d,
- wherein said high index ring-shaped region closest to said core has a thickness, δ, between about 0.1 to 5 times the maximum thickness, d, such that said fiber has zero dispersion at a tailored wavelength.
Dependencies are inferred from the claim text.