Small diameter low attenuation optical fiber
An optical fiber comprising: a core having an outer radius r 1 ; a cladding having an outer radius r 4 <45 microns; a primary coating surrounding the cladding and having an outer radius r 5 and a thickness t p >8 microns, the primary coating having in situ modulus E P of 0.35 MPa or less and a spring constant χ P <1.6 MPa, where χ P =2E P r 4 /t P ; and a secondary coating surrounding said primary coating, the secondary coating having an outer radius r 6 , a thickness t S =r 6 −r 5 , in situ modulus E S of 1200 MPa or greater, wherein >10 microns and r 6 ≤85 microns. The fiber has a mode field diameter MFD greater than 8.2 microns at 1310 nm; a cutoff wavelength of less than 1310 nm; and a bend loss at a wavelength of 1550 nm, when wrapped around a mandrel having a diameter of 10 mm, of less than 1.0 dB/turn.
1 . An optical fiber comprising:
a core, said core having an outer radius r 1 , wherein r 1 is 3.6 microns to 5.4 microns;
a cladding surrounding said core, said cladding having an outer radius r 4 , wherein r 4 is less than 45 microns;
a primary coating surrounding said cladding, said primary coating having an outer radius r 5 and a thickness t P >8 microns, an in situ modulus E P , wherein E P is 0.35 MPa or less, and a spring constant χ P <1.6 MPa, where χ P =2E P r 4 /t P ; and
a secondary coating surrounding said primary coating, said secondary coating having an outer radius r 6 and a thickness t S =r 6 −r 5 , and an in situ modulus E S of 1200 MPa or greater,
wherein t S is greater than 10 microns, said outer radius r 6 is 85 microns or less, and said fiber has a mode field diameter MFD greater than 8.2 microns at 1310 nm, a fiber cutoff wavelength of less than 1310 nm, and
said fiber exhibits a bend loss when wrapped around a mandrel having a diameter of 10 mm, of less than 1.0 dB/turn at a wavelength of 1550 nm, and
said fiber exhibits a puncture resistance load greater than 30 grams and a wire mesh drum microbending attenuation of less than 0.5 dB/turn 0.5 dB/km at a wavelength of 1550 nm.
2 . The fiber of claim 1 , wherein t S >12 microns.
3 . The fiber of claim 1 , wherein 24 microns≤r 4 ≤45 microns.
4 . The fiber of claim 1 , wherein 38 microns≤r 4 ≤42 microns.
5 . The fiber of claim 1 , wherein 30 microns≤r 4 ≤35 microns.
6 . The fiber of claim 3 , wherein r 6 ≤75 microns.
7 . The fiber of claim 4 , wherein 75 microns≤r 6 ≤85 microns.
8 . The fiber of claim 5 , wherein 60 microns≤r 6 ≤65 microns.
9 . The fiber according to claim 2 , wherein 39 microns≤r 4 ≤41 microns and 75 microns≤r 6 ≤85 microns.
10 . The fiber according to claim 5 , wherein 30 microns≤r 4 ≤32.5 microns and 60 microns≤r 6 ≤75 microns.
11 . The fiber according to claim 1 , wherein χ P ≤1.3 MPa.
12 . The fiber according to claim 1 , wherein χ P ≤1.0 MPa.
13 . The fiber according to claim 1 , wherein 0.5≤t P /t S ≤1.5.
14 . The fiber according to claim 1 , wherein MFD is greater than 8.6 microns at 1310 nm.
15 . The fiber of claim 1 , wherein said cladding includes a first inner cladding region having an outer radius r 2 and a relative refractive index Δ 2 , and a second inner cladding region surrounding said first inner cladding region and having an outer radius r 3 , said second inner cladding region having a relative refractive index Δ 3 with a minimum value Δ 3MIN , wherein Δ 3MIN <−0.2%.
16 . The fiber of claim 15 , wherein said first inner cladding region is directly adjacent to said core and said relative refractive index Δ 2 is substantially constant between said outer core radius r 1 and said outer radius r 2 .
17 . The fiber of claim 15 , wherein −0.05≤Δ 2 ≤0.5.
18 . The fiber of claim 1 , wherein said fiber exhibits a bend loss, when turned about a mandrel having a diameter of 10 mm, of less than 0.5 dB/turn at a wavelength of 1550 nm.
19 . The fiber of claim 1 , wherein said primary coating has an in situ modulus of 0.3 MPa or less.
20 . The fiber of claim 1 , wherein said secondary coating has an in situ modulus of 1800 MPa or greater.
21 . The fiber of claim 1 , wherein r 4 is 38 to 42 microns, r 5 is 60 microns to 65 microns, and r 6 is 77.5 microns to 82.5 microns.
22 . The fiber of claim 1 , wherein r 4 is 38 microns to 42 microns, r 5 is 45 microns to 55 microns, r 6 is 60 microns to 65 microns.
23. An optical fiber comprising:
a core, said core having an outer radius r 1 , wherein r 1 is 3.6 microns to 5.4 microns;
a cladding surrounding said core, said cladding having an outer radius r 4 ;
a primary coating surrounding said cladding, said primary coating having an outer radius r 5 and a thickness t P >8 microns, an in situ modulus E P , wherein E P is 0.35 MPa or less, and a spring constant χ P <1.6 MPa, where χ P =2E P r 4 /t P ; and
a secondary coating surrounding said primary coating said secondary coating having an outer radius r 6 and a thickness t S =r 6 −r 5 , and an in situ modulus E S of 1200 MPa or greater, wherein t S is greater than 10 microns, said outer radius r 6 is 85 microns or less, and said fiber has a mode field diameter MFD greater than 8.2 microns at 1310 nm, a fiber cutoff wavelength of less than 1310 nm, and said fiber exhibits a bend loss when wrapped around a mandrel having a diameter of 10 mm, of less than 1.0 dB/turn at a wavelength of 1550 nm, and
said fiber exhibits a puncture resistance load greater than 20 grams and a wire mesh drum microbending attenuation of less than 0.5 dB/turn at a wavelength of 1550 nm.
24. The fiber of claim 23 , wherein t S >12 microns.
25. The fiber of claim 23 , wherein 24 microns≤r 4 ≤45 microns.
26. The fiber of claim 23 , wherein 38 microns≤r 4 ≤42 microns.
27. The fiber of claim 23 , wherein 30 microns≤r 4 ≤35 microns.
28. The fiber of claim 25 , wherein r 6 ≤75 microns.
29. The fiber of claim 26 , wherein 75 microns≤r 6 ≤85 microns.
30. The fiber of claim 27 , wherein 60 microns≤r 6 ≤65 microns.
31. The fiber according to claim 24 , wherein 39 microns≤r 4 ≤41 microns and 75 microns≤r 6 ≤85 microns.
32. The fiber according to claim 27 , wherein 30 microns≤r 4 ≤32.5 microns and 60 microns≤r 6 ≤75 microns.
33. The fiber according to claim 23 , wherein χ P ≤1.3 MPa.
34. The fiber according to claim 23 , wherein χ P ≤1.0 MPa.
35. The fiber according to claim 23 , wherein 0.5≤t P /t S ≤1.5.
36. The fiber according to claim 23 , wherein MFD is greater than 8.6 microns at 1310 nm.
37. The fiber of claim 23 , wherein said cladding includes a first inner cladding region having an outer radius r 2 and a relative refractive index Δ 2 , and a second inner cladding region surrounding said first inner cladding region and having an outer radius r 3 , said second inner cladding region having a relative refractive index Δ 3 with a minimum value Δ 3MIN , wherein Δ 3MIN <−0.2%.
38. The fiber of claim 37 , wherein said first inner cladding region is directly adjacent to said core and said relative refractive index Δ 2 is substantially constant between said outer core radius r 1 and said outer radius r 2 .
39. The fiber of claim 37 , wherein −0.05≤Δ 2 ≤0.5.
40. The fiber of claim 23 , wherein said fiber exhibits a bend loss, when turned about a mandrel having a diameter of 10 mm, of less than 0.5 dB/turn at a wavelength of 1550 nm.
41. The fiber of claim 23 , wherein said primary coating has an in situ modulus of 0.3 MPa or less.
42. The fiber of claim 23 , wherein said secondary coating has an in situ modulus of 1800 MPa or greater.
43. The fiber of claim 23 , wherein r 4 is 38 to 42 microns, r 5 is 60 microns to 65 microns, and r 6 is 77.5 microns to 82.5 microns.
44. The fiber of claim 23 , wherein r 4 is 38 microns to 42 microns, r 5 is 45 microns to 55 microns, r 6 is 60 microns to 65 microns.
45. The fiber of claim 23 , wherein r 4 <45 microns.
46. The fiber of claim 23 , wherein the puncture resistance load is greater than 30 grams.
47. The fiber of claim 23 , wherein 20 microns>t P >8 microns.