Patent ID: 8953939
Filing Date: 2015-02-10
Classification: H04B,H04J

Abstract:
1. A method of generating variable bit-rate QPSK signals comprising the steps of: receiving user data; applying a bit mapping to the received data, wherein said bit mapping is one selected from the group consisting of polarization multiplexing (PolMux) bit mapping, polarization modulation (PolMod) bit mapping and polarization switched (PolSw) bit mapping; applying the bit mapped data to a pair of optical IQ modulators, wherein each one of the modulators is driven by a portion of a split optical signal; and combining the outputs of the IQ modulators through the effect of a polarization combiner such that an optical QPSK signal is output wherein the optical QPSK signal exhibits polarization characteristics according to the bit mapping applied; wherein said output optical QPSK signal exhibits a bit rate selected from the group consisting of 4R, 3R, or 2R where R is a clock rate associated with a bit generator and wherein the inputs to both IQ modulators are configured such that the exclusive OR (XOR) of all the inputs equal 0.