Polarization splitter and rotator

A method of transmitting a plurality of optically modulated signals for output to a fiber system, the method comprising the steps of:

• providing a first laser source configured to emit light of a first wavelength having a first polarization and a second laser source configured to emit light of a second wavelength having the first polarization, the second wavelength being different than the first wavelength;
• receiving a first portion of the light emitted by the first laser source with a first modulator and a second portion of the light emitted by the first laser source with a second modulator;
• receiving a first portion of the light emitted by the second laser source with a third modulator and a second portion of the light emitted by the second laser source with a fourth modulator;
• outputting a first modulated optical signal from the first modulator, the first modulated optical signal having the first polarization;
• outputting a second modulated optical signal from the second modulator, the second modulated optical signal having the first polarization;
• outputting a third modulated optical signal from the third modulator, the third modulated optical signal having the first polarization;
• outputting a fourth modulated optical signal from the fourth modulator, the fourth modulated optical signal having the first polarization;
• multiplexing the first modulated optical signal and the third modulated optical signal to provide a first multiplexed optical signal having the first polarization;
• multiplexing the second modulated optical signal and the fourth modulated optical signal to provide a second multiplexed optical signal having the first polarization;
• altering the second multiplexed optical signal to have a second polarization, the second polarization being different from the first polarization;
• and
• combining the first multiplexed optical signal having the first polarization and the second multiplexed optical signal having the second polarization into a third optical signal.