Keysight Technologies 86120B, User Manual

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Measurements Applications
Measuring Coherence Length
The smaller the alpha factor, the shorter the coherence length.
Beta factor The beta factor is defined as the height of the fringe visibility envelope midway
between the zero optical path delay peak and the next peak relative to the height of
the envelope peak at zero path delay. The beta factor is always between 0 and 1.
The
smaller the beta factor, the more longitudinal modes (wavelengths) the laser
has.
Alpha factor
V
A
V
o
------
=
Beta factor
V
B
V
o
------
=