FIBER OPTIC PC CONNECTOR RADIUS OF CURVATURE

 Measuring connector radius:

 The radius of a properly polished connector should lie between 10mm. and 25mm.  With the smaller radius being preferred.  When you have the connector  centered properly on the microscope, and a clear fringe pattern is visible, the pattern should be a series of concentric circles with the highest point on the sphere, the Apex, centered on the fiber core.  The boundary between the ferrule and the fiber should be in focus, and centered in your field of view. 

 Adjust the zoom eyepiece to 20X , this will provide a field of view approximately 3 fiber diameters or 400 microns.  You may have to re-focus after zooming.

FIBER / FERRULE BOUNDARY

                 25 mm. RADIUS                                              10mm. RADIUS

          2 FRINGES / 5 TRANSITIONS                  6 FRINGES / 12 TRANSITIONS

 400X MAGNIFICATION

» 375mm. FIELD OF VIEW

Since even a radius of 10mm is very gradual, not enough fringes can be counted over the fiber diameter.  For that reason it is preferred to count the number of fringes found within the field of view.  Shown above are the fringe patterns for both 10mm. and 25mm.  Connectors that fall within these two values are considered acceptable.

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