IEC 60793-1-21:2001 pdf download

IEC 60793-1-21:2001 pdf download.optical fibres -Part 1-21: Measurement methods and test procedures-Coating geometry.
4 Definitions
For the purpose of this part of IEC 60793. the following definitions apply,
4.1
primary coating
one or more layers of protective coating material applied to the fibre cladding surface during or after the drawing to preserve the cladding surface and to give a minimum amount of required protection (e.g. a 250 pm protective coating)
4.2
secondary or bufter” coating
one or more layers of coating material applied over one or more layers of primary coated fibres In order to give additional required protection or to arrange fibres together In a particular structure (e.g. a 900 pm buffer coating, tight jacker or ribbon coating)
5 Reference test method
Method A is the reference test method (RTM), which is the one used to settle disputes,
6 Apparatus
Annexes A and B include layout drawings and other equipment requirements for each of the methods A and B. respectively.
7 Sampling and specimens
7.1 Specimen length
The specimen shall be a short length of fibre, or as specified in the detail specification.
7.2 Specimen end face
Because the end faces of the specimen are not involved in the measurement itself, it is not necessary to have tight end-face requirements.
8 Procedure
See annexes A and B for methods A and B. respectively.
9 Calculations
See annexes A and B for methods A and B. respectively.
10 Results
The following information shall be provided with each measurement:- date and title of measurement;
-identification and description of specimen;
– measurement results as required by the detail specification.
The following information shall be available upon request:
– length of specimen;
– measurement method used: A or B;
– description of measurement apparatus arrangement;- details of computation technique;
– date and details of the latest calibration.
11 Specification information
The detail specification shall specify the following information:- type of fibre to be measured;
-failure or acceptance criteria;
-information to be reported;
-deviations to the procedure that apply.
A.1 Apparatus
The apparatus may consist of an optical microscope or a laser gauge.
A.1..1 Optical microscope
See figure A.1 for a schematic diagram of typical test equipment.
A.1.1.1 Lens objective
Use a high-quality microscope lens objective, with transmitted light illumination.
A.1.1.2 Fibre holding arrangement
Provide a fixture to hold the fibre In the focal plane of the microscope, with the fibre axis perpendicular to the optical axis of the objective. Immerse the specimen in a suitable indexmatching fluid, and retain it by means of a cell made with a transparent material. II necessary. fix this cell on a rotating table, in order to position the specimen parallel to the cursor. Hold the cell assembly as a whole, or the fibre within the cell, by the fibre clamp in such a way that it may be rotated through at least 1BO, and be capable of being fixed in a sufficient number of positions for the purpose of measuring coating dimensions. The mechanical tolerances should be such that minimal repositioning and refocusing is required when the fibre is moved from one rotational position to another.
The image may be viewed directly using a that eyepiece or projected onto a charge-coupled device (CCD) camera and displayed on a monitor. A typical system magnification for the visual method is xlOO to x200, and for the camera method is typically x20; in the latter case the image is formed directly onto the CCD. Determine the dimensions of the fibre image by using the filar eyepiece wilti the visual method and by positioning an electronic cursor on the monitor, or by computer data analysis of a stored image with the camera method.
A.1.2 Laser gauge
See figure A.2 for a schematic diagram of typical test equipment.
A,1.2.1 General components
The apparatus shall consist of a laser source operating at a suitable wavelength (e.g. 633 nm). a scanning device and a detector. If necessary, a system of lenses may be used to collimate the beam onto the specimen,
&12.2 Fibre holding arrangement
Hold the specimen by means of a suitable rotating fibre clamp so that it is capable of rotating through at least 18O and being fixed in a sufficient number of positions while maintaining the fibre axis perpendicular to the optical axis of the apparatus.