MIL-PRF-49291 Fiber, Optical, \(Metric\) General Specification ForThis specification covers the general requirements and characteristics of optical fibers for signal transmission. The fiber is defined as the core, cladding, and protective coatings applied during the fiber drawing process.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12

MIL-PRF-49291D

4.7 Methods of inspection.

4.7.1 Equivalent test methods. The use of equivalent test methods is allowed subject to the following

conditions:

a. The allowance of an equivalent method is specified in this specification.

b. The manufacturer has conducted both test methods and has submitted complete test

data to the Preparing Activity (PA).

c. The PA has approved the use of that method by that manufacturer.

4.7.2 Visual and mechanical inspection. The optical fiber shall be inspected in accordance with

TIA-455-13 to verify that the design, construction, physical characteristics and dimensions, marking, and

workmanship are in accordance with the requirements of 3.4, 3.5, 3.8, and 3.9. Fiber length shall be

measured in accordance with TIA-455-133.

4.7.2.1 Fiber geometry. Fiber geometry shall be determined as specified below.

4.7.2.1.1 Core diameter (Type I fiber only). Core diameter shall be determined in accordance with

4.7.2.1.2 Mode field diameter (Type II fiber only). Mode field diameter shall be determined in

accordance with TIA-455-167 or TIA/EIA-455-132 method A (see 3.5.1.2.2). In the case of a dispute

between the two test methods, TIA-455-167 shall be used.

4.7.2.1.3 Core ovality (core noncircularity) (Type I fiber only). Core ovality shall be determined in

accordance with TIA-455-176 (see 3.5.1.2.3).

4.7.2.1.4 Cladding diameter. Cladding diameter shall be determined in accordance with TIA-455-176

4.7.2.1.5 Cladding ovality (cladding noncircularity). Cladding ovality shall be determined in accordance

with TIA-455-176 (see 3.5.1.2.5).

4.7.2.1.6 Core-to-cladding offset (core/cladding concentricity). Core-to-cladding offset shall be

determined in accordance with TIA-455-176 (see 3.5.1.2.6).

4.7.2.1.7 Coating diameter. Coating diameter shall be determined in accordance with TIA-455-195

4.7.2.1.8 Overall coating concentricity error. The overall coating concentricity error shall be determined

in accordance with TIA-455-195 (see 3.5.1.2.8).

4.7.2.1.9 Materials inspection. Materials inspection shall consist of certification, supported by verifying

data, that materials used in fabricating the delivered fiber are in accordance with the requirements of 3.4

and as specified (see 3.1).

4.7.2.2 Fiber mass/unit length. The fiber mass per unit length shall be determined in accordance with

EIA/TIA-455-173 using scales with an accuracy of �5 percent or better to verify conformance to the

requirements (see 3.5.1.3).

4.7.2.3 Tensile proof. Fiber proof test characteristics shall be determined in accordance with