MIL-PRF-49291/1B
Diameter (µm)
Circle (solid)
Inner
47.0
Second
53.0
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: ≤ 1.5 µm.
Fiber-to-coating: coating-cladding concentricity error ≤ 12.5 µm
(overall coating concentricity ratio (OCCR) ≥ 0.70 for 250 µm diameter coatings and ≥ 0.84 for 500 µm
diameter coatings).
Splices: Not allowed.
Fiber mass/unit length: 0.1 kg/km maximum.
Tensile proof: 690 MPa.
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: 0.20 ± 0.015 at 850 nm ± 25 nm.
Bandwidth: ≥ 500 MHZ-km at 1300 nm ± 20 nm.
≥ 500 MHZ-km at 850 nm ± 20 nm.
2