Digital polarization encoding based on orthogonal polarization rotation in a semiconductor optical amplifier

Abstract

We investigate the polarization-dependent mode gains and polarization rotation (PR) of the semiconductor optical amplifier in pump-probe scheme, and find that the relationship between polarization rotation (PR) and mode gains keeps well under different pump power. Thus we can simply obtain the PR angle by measurement of the mode gains. Choosing suitable injected current we realize the orthogonal polarization rotation by pump laser with power of ~3.5 mW. Then we propose a novel digital polarization encoding scheme and perform it well in a 10-km fiber transmission system with data rate at 2.5 G-bit/s, which is promising to promote the optical power-equalized encoding communications.