Multilevel polarization shift keying by using data induced polarization switching

A scheme to generate a 4-POLSK-tetrahadron signal from an equidistant four-level FSK signal is presented. For this purpose the transmitter laser equally excites the two polarization modes of a hibi fiber. This fiber is spliced at 45 degrees to a second hibi fiber with half the length of the first. In this scheme different optical frequencies are translated in certain states of polarization. The scheme is in principle passive. The insertion loss and complicated driving scheme of a polarization modulator are avoided. The viability of the scheme was demonstrated with simulations and an experiment.<
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