DSCOR. The upper plot shows the transmitter setup for a polarization-multiplexed
DQPSK signal. The output from a laser is equally split by a polarization beam splitter
(PBS) into two orthogonally polarized components, each of which is modulated by
DQPSK at 20 Gb/s. A second PBS combines the two generic DQPSK signals into a
40-Gb/s polarization-multiplexed DQPSK signal. For better signal performance, RZ
pulse formatting can be used, in which case polarization bit-interleaving may be
optionally used to improve signal tolerance to nonlinearity. The received optical
signal is first split by a PBS into two orthogonally polarized components, each of
which is differentially detected and sampled according to the single-polarization
DSCOR architecture descri ...