Polarization Dependence of Linewidth Enhancement Factor in Semiconductor Optical Amplifier and Its Implication for Nonlinear Polarization Rotation

Linewidth enhancement factors (LEFs) of the transverse electric mode and the transverse magnetic mode in bulk semiconductor optical amplifiers are measured using the nonlinear optical loop mirror method and the principal state of polarization vector method. The polarization dependence of LEFs plays an important role in the nonlinear polarization rotation. The relationship between the polarization-dependence of LEFs and nonlinear polarization rotation in the Stokes space is demonstrated.