IEC 60793-1-45:2001 pdf download
IEC 60793-1-45:2001 pdf download.Optical fibres -Part 1-45: Measurement methods and test procedures -Mode field diameter.
2 Normative references
The following normative documents contain provisions which, through reference in this text. constitute provisions of this part of IEC 60793. For dated references, subsequent amendments to. or revisions of. any of these publications do not apply. However, parties to agreements based on this part of IEC 60793 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 60793-1-40, Optical fibres — Part 1-40: Measurement methods and test procedures — Attenuation
IEC 60793-2:1998, Optical fibres — Part 2: Product specifications
3 Reference test method
Method A, direct far-field scan, is the reference test method (RTM), which shall be the one used to settle disputes.
4 Apparatus
The following apparatus is common to all measurement methods. Annexes A. B. C and D Include layout drawings and other equipment requirements for each of the four methods, respectively.
4.1 LIght source
For methods A, B and C, u5e a suitable coherent or non—coherent light source such as a semiconductor laser or a sufficiently powerful filtered white light source. The source shall produce sufficient radiation at the intended wavelength(s) and be stable in intensity over a time period sufficient to perform the measurement.
A monochromator or interference filter(s) may be used, if required, for wavelength selection. The detail specification shall specify the wavelength of the source. The FWHM (full width half maximum) spectral line width of the source shall be less than or equal to 10 nm, unless otherwise specified.
See annex D for method D.
4.2 Input optics
For method A, B, and C. an optical lens system or fibre pigtail may be employed to excite the specimen. It is recommended that the power coupled into the specimen be relatively insensitive to the position of Its Input end face. This can be accomplished by using a launch beam that spatially and angularly overfills the input end face.
If using a butt splice, employ index-matching material between the fibre pigtail and the specimen to avoid Interference effects. The coupling shall be stable for the duration of the measurement,
See annex D for method D.
4.3 Input posltlon.r
Provide means of positioning the input end of the specimen to the light source. Examples include the use of x-y-z micropositioner stages, or mechanical coupling devices such as connectors, vacuum splices, three-rod splices, etc. The position of the fibre shall remain stable over the duration of the measurement.
4.4 Cladding mode stripper
Use a device that extracts cladding modes. Under some circumstances the fibre coating will
perform this tunction
4.5 High-order mode filter
Use a means to remove high-order propagating modes in the wavelength range that is greater than or equal to the cut-oft wavelength of the specimen. For example, a one-turn bend with a radius of 30 mm on the fibre is generally sufficient
4.6 Output positloner
Provide a suitable means for aligning the fibre output end race in order to allow an accurate axial adjustment of the output end, such that, at the measurement wavelength, the scan pattern is suitably focused on the plane of the scanning detector. Such coupling may include the use of lenses, or may be a mechanical connector to a detector pigtail.
Provide means such as a side-viewing microscope or camera with a crosshair to locate the fibre at a fixed distance from the apertures or detectors. It may be sufficient to provide only longitudinal adjustment if the fibre is constrained in the lateral plane by a device such as a vacuum chuck. (This depends mainly upon the size of the light detector.)
4.7 Output optics
See the appropriate annex: A. B, C or D.
4.8 Detector
See the appropriate annex: A, B, C or D.
4.9 Computer
Use a computer to perform operations such as controlling the apparatus, taking intensity measurements, and processing the data to obtain the final results. For individual details, see the appropriate annex: A, B, C or D.
5 Sampling and specimens
5.1 Specimen length
For methods A, B and C, the specimen shall be a known length, typically 2 m * 0,2 m of single- mode fibre.
NOTE For m.lhod 0, OTDR, the ..mpl. must be Ion enough Ia .iic..d for be posihoned beyond) the deed zone of the OTOR. with both ends accessible, as described In the backscatter test method IEC 60753-1-40.
