A method of noise reduction in a system where polarization mode
fluctuations contribute to the noise in a signal is provided.
Specifically, a corrected signal is formed by adjusting the relative and
overall intensity of the orthogonal polarization components of an
unpolarized laser source at a first detector positioned at a first angle
with respect to the laser beam axis so that the first detector has the
same sensitivity to polarization as a second detector positioned at a
second angle with respect to the laser beam axis. This corrected signal
is then subtracted from the signal at the second detector which detects a
desired signal.