Chapter Iv Working Principles; Working Principles; Event Point Type - Yamasaki Y30 Series User Manual

1 Working Principles

During optical transmission via the optical fiber, small changes in optical fiber refractive index can
result in rayleigh scattering, and refractive index saltation on the end face or failure point of the
optical fiber can result in Fresnel reflection. Loss distribution and fusion loss can be determined by
observing the backward rayleigh scattering strength change, and the optical fiber breakpoint and
failure point determined by observing the Fresnel reflection.

2 Event point type

The event points on the optical fiber curve under test can be divided into two types, namely, the
reflection event point and non-reflection event point.
The reflection event point is generally caused due to crack of the fixed connector or the fiber end,
displaying a peak. It is as shown in the figure below.
Fiber end with reflection
Reflection event point
Non-reflection event includes the following generally: (as shown in the figure below)
 Descending event point
 Ascending event point
 Fiber end without reflection
Ascending event point
Descending event point
Appendix A Cleaning the optical output port

Chapter IV Working Principles

Fiber end without
reflection
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