Combinatorial polarization scramblers for many-segment PMD emulator

In this letter, we present a combinatorial approach to build polarization scramblers in a many-segment polarization-mode dispersion (PMD) emulator. This approach significantly reduces the required number of phase plates and their corresponding controls. It exploits the fact that rotation matrices are noncommutative which gives many different ways of building polarization scramblers out of just a few phase plates. Although these polarization scramblers are correlated, we show, numerically and experimentally, that there is sufficient polarization scrambling between segments to achieve the important key properties of a PMD emulator.