A optical transmitter and method for transmitting digital data on an optical channel, performing the steps of generating first and second baseband digital signals, modulating a first polarized optical carrier wave component in accordance with the first baseband digital signal, modulating a second polarized optical carrier wave component in accordance with the second baseband digital signal, wherein the second polarized optical carrier wave component has an orthogonal polarization to the first polarized optical carrier wave component and combining the first and second modulated optical carrier wave components into a propagation medium. The first and second baseband digital signals are generated in a correlated manner so that the modulated optical carrier wave components are combined as a modulated single-polarization optical carrier wave.