MIL-PRF-49291/6C
Cladding boundary
Reticle
Cladding boundary
Circle (solid)
Diameter (µm)
Inner
59.5
Second
65.5
Third
124.0
Fourth
126.0
FIGURE 2.
Tolerance fields.
DIMENSIONS AND CONFIGURATION:
Diameter: See figures 1 and 2. (Diameter requirements are based on
selecting fibers with end-points tolerances of 125 ± 1 µm from production
with a 125 ± 2 µm tolerance.)
Ovality:
Core: < 6 percent.
Cladding: < 2 percent.
Offset:
Core-to-cladding: < 4 µm.
Fiber-to-coating: coating-cladding concentricity error < 10.5 µm
(overall coating concentricity ratio (OCCR) > 0.70 for 250 µm diameter
coatings and > 0.84 for 500 µm diameter coatings).
Splices:
Not allowed.
Tensile strength (proof test):
690 MPa.
Fiber mass/unit length:
0.1 kg/km maximum.
Change in optical transmittance:
Measurements to be made at 1300 ± 20 nm.
Maximum attenuation rate:
3.5 dB/km at 850 ± 20 nm
1.0 dB/km at 1300 ± 20 nm
Numerical aperture:
0.275 ± 0.015 at 850 nm ± 25 nm.
2