MIL-PRF-85045/20B
Short-term minimum bend diameter: Eight times the cable outer diameter. (The short-term minimum bend
diameter is to be used in all environmental and mechanical tests which specify a cable minimum bend diameter.)
Long-term minimum bend diameter: Sixteen times the cable outer diameter.
Minimum continuous length: The minimum continuous length of all cables shall be not less than 0.5 km. If
lengths less than 0.5 km are specified in the purchase order, a conformance inspection shall be performed on test
specimens not less than 0.5 km in length from which the purchase order lengths are cut.
Cable jacket color: Shall be black or blue.
PERFORMANCE REQUIREMENTS:
Optical properties:
Maximum attenuation rate:
5.6 dB/km at 850±20 nm, 2.0 dB/km at 1300±20 nm for Type MM fiber.
1.5 dB/km at 1310±20 nm and 1550±20 nm for Type SM fiber.
For cables with radiation cross-linked jackets, the change in attenuation rate measurement may be made up to
30 days after cross-linking of the cable jacket.
Bandwidth: Fiber with a minimum bandwidth of 500 MHz-km at 1300 nm shall be used (multimode cables
only).
Bandwidth is not specified at 850 nm.
Change in optical transmittance: Measurements shall be made at 1300±20 nm. A minimum of eight fibers shall
be monitored for change in optical transmittance. A minimum of two fibers shall be monitored in the inner ring of
OFCCs. A minimum of two fibers shall be monitored in the middle ring of OFCCs. A minimum of four fibers shall
be monitored in the outer ring of OFCCs. The fibers monitored in each ring shall be randomly selected, but
different fibers shall be monitored in each test sample. For shock testing, only four fibers are required to be
monitored (one in the inner ring, one in the middle ring, and two in the outer ring of OFCCs).
Crosstalk: Applicable. For the optical measurement, a minimum of the two fibers adjacent to the active fiber
are measured (e.g., active fiber is #31, measure crosstalk on 30 and 32). Repeat the process for a total of three active
fibers per sample/unit.
Mechanical properties:
Tensile loading and elongation: Applicable, tensile loading >3,300 N.
Low temperature flexibility: The exposure temperature shall be -40 °C.
Cyclic flexing: 500 cycles at +25±2 °C and 100 cycles at -28±2 °C. Change in optical transmittance
measurements are to be made every 100 cycles for the 500-cycle exposure and every 25 cycles for the 100-cycle
exposure. Each change in optical transmittance measurement shall be performed with the test specimen in the same
position in the test cycle. The cycling may be halted to perform the change in optical transmittance measurement.
Cable twist-bending: 500 cycles at +25±2 °C and 100 cycles at -28±2 °C. Change in optical transmittance
measurements are to be made every 100 cycles for the 500-cycle exposure and every 25 cycles for the 100-cycle
exposure. Each change in optical transmittance measurement shall be performed with the test specimen in the same
position in the test cycle. The cycling may be halted to perform the change in optical transmittance measurement.
Impact: 50 cycles at +25±2 °C and 20 cycles at -40±2 °C. Minor jacket damage such as splitting or cracking is
permitted at the low test temperature.
Hosing: Low pressure applicable, except the cable leakage shall be not greater than 135 ml.
Hydrostatic: 2.1 MPa
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