Wide bandwidth, low loss photonic bandgap fibers
Various embodiments include photonic bandgap fibers (PBGF). Some PBGF embodiments have a hollow core (HC) and may have a square lattice (SQL). In various embodiments, SQL PBGF can have a cladding region including 2-10 layers of air-holes. In various embodiments, an HC SQL PBGF can be configured to provide a relative wavelength transmission window Δλ/λc larger than about 0.35 and a minimum transmission loss in a range from about 70 dB/km to about 0.1 dB/km. In some embodiments, the HC SQL PBGF can be a polarization maintaining fiber. Methods of fabricating PBGF are also disclosed along with some examples of fabricated fibers. Various applications of PBGF are also described.
1. A photonic bandgap fiber (PBGF) for propagating light having a wavelength, λ, said fiber comprising:
a core; and
a cladding disposed about said core,
wherein said cladding comprises a plurality of regions, at least one region having a dimension, Λ, and is configured such that the cladding at least partially surrounds a hole having a hole dimension, D,
wherein said plurality of regions are arranged as a rectangular lattice,
wherein said portions of said cladding form webs and nodes of said lattice such that at least a portion of said webs have a dimension, d 2 , and are configured as higher aspect ratio cladding material portions,
wherein a portion of the webs are connected to said nodes, at least a portion of said nodes having a dimension, d 1 , and configured as lower aspect ratio cladding material portions, and
wherein D/Λ is in a range from about 0.9 to about 0.995 and said PBGF is configured such that a relative wavelength transmission window Δλ/λc is larger than about 0.35.
2. The photonic bandgap fiber of claim 1 , wherein the webs have a second dimension d 3 , such that the ratio of d 3 to d 2 is at least approximately 5:1.
3. The photonic bandgap fiber of claim 2 , wherein the ratio of d 3 to d 2 is at least approximately 10:1.
4. The photonic bandgap fiber of claim 2 , wherein the ratio of d 3 to d 2 is at least approximately 25:1.
5. The photonic bandgap fiber according to claim 1 , d 2 /Λ is in a range from about 0.01 to about 0.1, and d 1 /Λ in a range from about 0.1 to about 0.5.
6. The photonic bandgap fiber according to claim 1 , wherein Δλ/λc is in the range from about 0.35 to about 0.65.
7. The photonic bandgap fiber according to claim 1 , wherein said rectangular lattice comprises 2 to 5 layers of cladding regions.
8. The photonic bandgap fiber according to claim 1 , wherein said fiber is drawn from a preform having webs and nodes having sizes larger than d 1 and d 2 , and said PBGF is configured such that a relative reduction in the node size is substantially less than a relative reduction in the web size.
9. The photonic bandgap fiber according to claim 8 , wherein said preform is configured with preform parameters D/Λ in a range from 0.5 to 0.95, d 2 /Λ in a range from 0.05 to 0.5, and d 1 /Λ in a range from 0.2 to 0.6.
10. The photonic bandgap fiber of claim 1 , wherein an air filling fraction of the cladding region exceeds about 80%, and is up to about 95%.
11. The photonic bandgap fiber according to claim 1 , wherein a dimension of said core is in a range from about 10 μm to about 100 μm.
12. The photonic bandgap fiber according to claim 1 , wherein said fiber is configured as a polarization maintaining (PM) square lattice (SQL) PBGF.
13. The photonic bandgap fiber according to claim 1 , wherein said holes contain air.
14. The photonic bandgap fiber according to claim 1 , wherein at least a portion of said high index cladding glass comprises silica.
15. A method of fabricating a photonic bandgap fiber of claim 1 , comprising:
stacking capillaries and rods to form a rectangular lattice, said rods comprising an optical material;
constructing a preform;
drawing said preform into a fiber; and
controlling core and cladding pressure during said drawing, said core and cladding pressurized with different pressures, said controlling narrowing a web dimension, d 2 , and substantially limiting changes in node dimension, d 1 , of said photonic bandgap fiber such that D/Λ is in a range from about 0.9 to about 0.99.
16. The method of claim 15 , wherein cladding holes are pressurized from about 0.5 to about 2.5 psi and said core is pressurized from about of 0.2 to about 2 psi, and said pressurization of cladding holes exceeds pressurization of said core.
17. The method of claim 15 , wherein a web dimension, d 2 , is less than about 0.25 μm.
18. A method of manufacturing a polarization maintaining photonic bandgap fiber, comprising:
forming a cane comprising a lattice of cladding regions having four-fold symmetry, a core, and a having substantially circular outer diameter, said canes comprising an optical material;
forming a circular preform using said cane;
modifying said circular preform to form a non-circular shape;
drawing said preform into a fiber; and
transforming said four-fold symmetry of said lattice into two-fold symmetry by deforming said core and said cladding during said drawing thereby introducing birefringence into said fiber.
19. The method of claim 18 , wherein said non-circular shape comprises flat boundary portions disposed opposite each other, and at a non-zero angle relative to axes defining said lattice.
20. The method of claim 18 , wherein said lattice comprises a rectangular lattice.
21. A system for telecommunications, gas measurement, delivery of high peak power pulses, or laser pulse shaping, comprising a PBGF according to claim 1 .
22. A SQL photonic bandgap fiber having a cladding region comprising 2-10 layers of air-holes and configured to provide a relative wavelength transmission window Δλ/λc larger than about 0.35 and minimum transmission loss in a range from about 70 dB/km to about 0.1 dB/km.
23. A photonic bandgap fiber (PBGF) for propagating light having a wavelength, λ, said fiber comprising:
a core; and
a cladding region disposed about said core,
wherein said cladding region comprises a plurality of features, said features having a periodicity, Λ, and is configured such that the cladding region at least partially surrounds a hole having a hole dimension, D,
wherein said plurality of features are arranged as a rectangular lattice,
wherein said cladding region comprises webs and nodes of said lattice such that said webs have a width, d 2 , and are configured as higher aspect ratio cladding material portions,
wherein the webs are connected to said nodes, said nodes having a dimension, d 1 , and configured as lower aspect ratio cladding material portions, and
wherein D/Λ is in a range from about 0.9 to about 0.995 and said PBGF is configured such that a relative wavelength transmission window Δλ/λc is larger than about 0.35.
24. A photonic bandgap fiber (PBGF) for propagating light having a wavelength, λ, said fiber comprising:
a core; and
a cladding disposed about said core,
wherein said cladding comprises a plurality of regions, at least one region having a dimension, Λ, and is configured such that the cladding at least partially surrounds a hole having a hole dimension, D,
wherein said plurality of regions are arranged as a rectangular lattice,
wherein said portions of said cladding form webs and nodes of said lattice such that at least a portion of said webs have a dimension, d 2 , and are configured as higher aspect ratio cladding material portions,
wherein a portion of the webs are connected to said nodes, at least a portion of said nodes having a dimension, d 1 , and configured as lower aspect ratio cladding material portions, and wherein the rectangular lattice comprises 2 to 5 layers of cladding material; and
wherein D/Λ is in a range from about 0.9 to about 0.995 and said PBGF is configured such that d 2 /d 1 is less than approximately 0.15, d 1 /Λ is in a range from about 0.05 to about 0.3, and said PBGF is configured such that Δλ/λc is in the range from about 0.35 to about 0.85.
25. The photonic bandgap fiber according to claim 24 , wherein Δλ/λc is in the range from about 0.5 to about 0.85.
26. The photonic bandgap fiber according to claim 24 , wherein the PBGF has a relative bandgap greater than approximately 0.4.
27. A method of fabricating a PBGF of claim 24 , the method comprising:
constructing a perform, said constructing comprising stacking capillaries and rods to form a rectangular lattice, said rods comprising an optical material;
drawing said preform into the PBG fiber; and
controlling core and cladding pressure during said drawing, said core and cladding pressurized with different pressures, said controlling relatively narrowing a web dimension, d 2 , and substantially limiting relative changes in node dimension, d 1 , of said PBGF such that D/Λ is in a range from about 0.9 to about 0.99.
28. The method according to claim 27 , wherein cladding holes are pressurized from about 0.5 to about 2.5 psi and said core is pressurized from about of 0.2 to about 2 psi, and said pressurization of cladding holes exceeds pressurization of said core.
29. The method according to claim 27 , wherein a web dimension, d 2 , is less than about 0.25 μm.