
33Optical Fibers: Geometrical and Guiding Properties
with
the variation of b = β/k as the normalized propagation constant and the V parameter
is shown in Figure 2.6d. There are two possible polarized modes, the horizontal and verti-
cal
polarizations, which are orthogonal to each other. These two polarized modes can be
employed for transmission of different information channels. They are currently exploited
in optical transmission systems employing polarization division multiplexed (PDM) in
association with QPSK (quadrature phase-shift keying) modulation formats so as to offer
a transmission bit rate of 100 Gb/s and beyond. This is derived ...