IEC 61300-3-23:1998 pdf download.Fibre optic interconnecting devices and passive components – Basic test and measurement procedures
1 General
1.1 Scope and object
The purpose of the procedure described this part of IEC 61 300 is to measure the fibre position
relative to the ferrule endface of a spherically polished ferrule, that is a fibre undercut or a fibre
protrusion.
1.2 General description
The fibre undercut + w or protrusion – w of a spherically polished ferrule is defined as the
average distance between a fibre endface and a virtual spherical surface which is fitted to the
spherically polished ferrule endface. It is assumed that a circle region of the ferrule endface,
which is centred to the ferrule axis, is spherical, although in practice the endface is often
aspherical.
Three methods are described in this standard for measuring the fibre undercut or protrusion:
a) method 1 : analyzing the endface with a two-dimensional surface analyzer;
b) method 2: analyzing the endface with a three-dimensional interferometry type surface analyzer;
c) method 3: analyzing the endface with a two-dimensional interferometry type surface analyzer.
Method 1 is the reference method.
2 Apparatus
2.1 Method 1 – Two-dimensional surface analysis
The apparatus shown in figure 2 consists of a suitable ferrule holder, a positioning stage and a two-dimensional surface analyzer.
2.1.1 Ferrule holder
The ferrule holder is a suitable device to hold the ferrule in a fixed vertical position, or in a tilted
position in the case of an angled ferrule type.
2.1.2 Positioning stage
The ferrule holder is fixed to the positioning stage, which shall enable the holder to be moved
to the appropriate position. The stage shall have enough rigidity so as to measure the ferrule
endface with a precision of some nanometres.
2.1.3 Two-dimensional surface analyzer
The two-dimensional surface analyzer shall have an ability to measure the profile of the ferrule endface with an accuracy better than ±1 0 nm. The analyzer shall consist of a profilometer, a profile data processing unit and a monitor. The profilometer shall be equipped with a wedge type probe arranged so that the motion of the trace is perpendicular to the ferrule axis. The profile data processing unit shall be able to process the profile data so as to measure the fibre undercut or protrusion: the unit calculates an ideal circle fitted to the spherical ferrule endface from the measured profile data and calculates converted data from the measured profile data by extracting the ideal circle data. The monitor shall display the measured and calculated profiles.
2.2 Method 2 – Three-dimensional surface analysis by interferometry system
The apparatus shown in figure 3 consists of a suitable ferrule holder, a positioning stage and a
three-dimensional interferometry analyzer.
2.2.1 Ferrule holder
The ferrule holder is a suitable device to hold the ferrule in a fixed vertical position, or in a tilted
position in the case of an angled ferrule type.
2.2.2 Positioning stage
The ferrule holder is fixed to the positioning stage, which shall enable the holder to be moved
to the appropriate position. The stage shall have enough rigidity so as to measure the ferrule
endface with a precision of some nanometres.
2.2.3 Three-dimensional interferometry analyzer
The three-dimensional interferometry analyzer shall have an ability to measure the surface of the ferrule endface with an accuracy better than ±1 0 nm. The analyzer shall consist of a microscope unit, a surface data processing unit, and a monitor. The microscope unit shall consist of an interference microscope, an actuator, and an image scanner. The interference microscope equipped with an objective is arranged so that its motion is parallel to the axis of the ferrule. The actuator transports the objective vertically. The image scanner converts interference image signals into position data. The surface data processing unit shall be able to process the position data so as to measure the fibre undercut or protrusion: the unit calculates an ideal spherical surface fitted to the spherical ferrule endface from the measured surface data and calculates converted surface data from the measured surface data by extracting the ideal spherical surface data. The unit also has an ability to correct the surface data taking into account the difference in refractive indices and absorption coefficients of the fibre and the ferrule. The monitor shall display the measured and calculated three-dimensional surface profiles.
IEC 61300-3-23:1998 pdf download
