Low bend loss single mode optical fiber
An optical fiber comprising: (i) a core region comprising an outer radius r 1 , and 3.0≤r 1 ≤7.0 microns and a relative refractive index Δ 1max and 0.32%≤Δ 1max ≤0.5%; (b) a depressed index cladding region surrounding the core region comprising an outer radius r 3 and a relative refractive index Δ 3 less than −0.2%, and trench volume V 3 wherein 45% Δ-micron 2 ≤|V 3 |≤200% Δ-micron 2 ; (c) a first outer cladding region surrounding the depressed index cladding region and comprising a relative refractive index Δ 4 and an outer radius r 4 ; and (d) a second outer cladding layer comprising 5 wt %-20 wt % titania, a relative refractive index Δ 5 , and a thickness T M , wherein 3 micron≤T M ≤30 microns, and outer radius r 5 ≤65 microns; the optical fiber has a mode field diameter MFD 1550 and 8 microns≤MFD 1550 ≤10.5 microns, a cutoff wavelength ≤1550 nm when bent 1 turn around a 2.5 mm radius mandrel, and a bending loss at 1550 nm when using a mandrel comprising a radius of 2.5 mm of ≤1.0 dB/turn.
1. An optical fiber comprising:
a core region comprising an outer radius r 1 and 3.0≤r 1 ≤7.0 microns and a relative refractive index Δ 1max and 0.32%≤Δ 1max ≤0.5%;
a depressed index cladding region surrounding said core region, said depressed index cladding region comprising an outer radius r 3 and a relative refractive index Δ 3 less than −0.2%, and a trench volume V 3 such that 45% Δ-micron 2 ≤|V 3 |≤200% Δ-micron 2 ;
a first outer cladding region surrounding said depressed index cladding region, said outer cladding region comprising a relative refractive index Δ 4 and an outer radius r 4 ; and
a second outer cladding layer a relative refractive index Δ 5 , said second outer cladding region comprising silica based glass doped with 5 to 20 wt % titania and having a thickness T M , such that 3 micron≤T M ≤30 microns, the second outer layer having an outer radius r 5 of not greater than 65 microns;
wherein said optical fiber has a mode field diameter at 1550 nm (MFD 1550 ) is 8.3 microns≤MFD 1550 ≤10.5 microns, a fiber cutoff wavelength <1550 nm when bent 1 turn around a 2.5 mm radius mandrel, an effective area at 1550 nm of at least 65 micron 2 and less than 85 micron 2 , and a bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm-of ≤1.0 dB/turn.
2. The optical fiber of claim 1 , wherein said fiber exhibits bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm-of ≤0.55 dB/turn.
3. The optical fiber of claim 1 , wherein said fiber exhibits bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm-of ≤0.1 dB/turn.
4. The optical fiber of claim 1 , wherein said fiber exhibits bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm of ≤0.01 dB/turn.
5. The optical fiber of claim 1 , wherein the outer radius r 1 of the core region is 3.0≤r 1 ≤6, and 70% Δ-micron 2 ≤|V 3 |≤150% Δ-micron 2 .
6. The optical fiber of claim 1 , wherein 80% Δ-micron 2 ≤|V 3 |≤200% Δ-micron 2 .
7. The optical fiber of claim 1 , wherein 100% Δ-micron 2 ≤|V 3 |≤150% Δ-micron 2 .
8. The optical fiber of claim 1 , wherein 10 microns≤r 5 ≤63 microns.
9. The optical fiber of claim 1 , wherein 10 microns≤r 5 ≤50 microns.
10. The optical fiber of claim 1 , wherein 30 microns≤r 5 ≤62.5 microns.
11. The optical fiber of claim 1 , wherein the optical fiber has a 22 m cable cutoff wavelength less than 1550 nm.
12. The optical fiber of claim 1 , wherein said a second outer cladding layer comprises 5 to 15 wt % Mania, and 5 micron≤T M ≤15 microns.
13. The optical fiber of claim 1 , wherein said mode field diameter at 1550 nm (MFD 1550 ) is 9 microns≤MFD 1550 ≤10 microns.
14. The optical fiber of claim 1 , wherein the depressed index cladding region Δ 3 of −0.2%≤Δ 3 ≤−0.7%.
15. The optical fiber of claim 1 , wherein the depressed index cladding region Δ 3 of −0.3%≤Δ 3 ≤−0.5%.
16. The optical fiber of claim 1 , wherein the core region comprises α, and 10≤α≤100.
17. The optical fiber of claim 1 , wherein the central core region of said fiber exhibits an alpha 1≤α≤10.
18. The fiber of claim 1 , wherein the optical fiber exhibits:
MFD at 1550 nm>9 microns;
cable cutoff wavelength greater than 1260 nm and less than <1540 nm;
bend loss at 2.5 mm radius mandrel≤1 dB/turn;
bend loss at 5 mm radius mandrel<0.5 dB/turn
wherein the bend loss is macrobend loss and is measured at 1550 nm wavelength.
19. The fiber of claim 18 , wherein the optical fiber exhibits macrobend loss bend loss at radius mandrel f not greater than ≤0.55 dB/turn.
20. The fiber of claim 1 , wherein the optical fiber exhibits:
1200 nm<cable cutoff wavelength<1540 nm;
0.001 dB/turn<macrobend loss at 2.5 mm bend radius<0.55 dB/turn; and
0.001 dB/turn<macrobend loss at 5 mm bend radius<0.5 dB/turn;
wherein the macrobend loss is measured at 1550 nm wavelength.
21. The optical fiber of claim 1 , wherein said fiber includes a coating surrounding the second outer cladding layer, said coating comprises: a primary coating P having a Young's modulus 0.1 to 1 MPa; and a secondary coating S having a Young's modulus of 1100 MPa to 2500 MPa, wherein the secondary coating has an outer coating diameter of not greater than 242 microns.
22. The fiber of claim 1 , wherein the single mode cutoff wavelength is between 1100 nm and 1450 nm when the fiber bent 1 turn around a 2.5 mm radius mandrel.
23. A micro-optic device comprising:
a. a silicon-photonics chip;
b. an optical fiber having a section bent to a bend radius of ≤5 mm, said fiber being coupled to said silicon-photonics chip; the fiber comprising:
a core region comprising an outer radius r 1 in the range from 3.0 to 7.0 microns and a relative refractive index Δ 1max in the range from 0.32% to 0.5%;
a depressed index cladding region surrounding said core region, said depressed index cladding region comprising an outer radius r 3 and a relative refractive index Δ 3 less than −0.2%, and a trench volume V 3 such that 60% Δ-micron 2 ≤|V 3 |≤200% Δ-micron 2 ;
a first outer cladding region surrounding said depressed index cladding region, said outer cladding region comprising a relative refractive index Δ 4 and an outer radius r 4 ; and
a second outer cladding layer a relative refractive index Δ 5 and an outer radius r 5 , said second outer cladding region comprising silica based glass doped with 5 to 20 wt % titania and having a thickness T M , such that 3 micron≤T M ≤30 microns, the second outer layer having an outer radius of not greater than 65 microns;
wherein said optical fiber has: a mode field diameter at 1550 nm (MFD 1550 ) and 8.3 microns≤MFD 1550 ≤10.5 microns, a single mode cutoff wavelength <1550 nm when bent 1 turn around a 2.5 mm radius mandrel, an effective area at 1550 nm of at least 65 micron 2 and less than 85 micron 2 , and a bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm-of ≤1.0 dB/turn.
24. The micro-optic device of claim 23 wherein the bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm-of ≤0.55 dB/turn.
25. The micro-optic device of claim 23 , wherein the optical fiber has a section bent to a bend radius of ≤3 mm.
26. The micro-optic device of claim 23 , wherein an optical fiber has a section bent to a bend radius of ≤2.5 mm but not less than 0.5 mm.
27. The micro-optic device of claim 23 , wherein the optical fiber has a mode field diameter at 1550 nm (MFD 1550 ) is 8.5 microns≤MFD 1550 ≤10 microns, and the bending loss at 1550 nm as determined by the mandrel wrap test using a mandrel comprising a radius of 2.5 mm between 0.01 dB/turn and 0.55 dB/turn.
28. The micro-optic device of claim 23 , wherein 80% Δ-micron 2 ≤|V 3 |≤200% Δ-micron 2 .