Extinction ratio
In
telecommunication,
extinction ratio (
r e ) is the
ratio of two optical
power levels, of a
digital signal generated by an optical source,
e.g., a
laser diode, where
P 1 is the optical
power level generated when the
light source is "on," and
P 2 is the power level generated when the light source is "off."
Note: The extinction ratio may be expressed as a fraction or in dB.
Source: from Federal Standard 1037C and from MIL-STD-2196