Design and ASE characteristics of 1550-nm polarization-insensitive semiconductor optical amplifiers containing tensile and compressive wells

The polarization dependence of 1550-nm semiconductor optical amplifiers (SOA´s) containing tensile and compressive wells has been investigated both theoretically and experimentally. Our model to predict the polarization-resolved (TE and TM) gain spectra of these structures has been confirmed by amplified spontaneous emission measurements. It is found that there can be appreciable carrier redistribution between the two types of wells when the tensile layers have the large thickness (greater than 100 /spl Aring/) needed for gain at wavelengths around 1550 nm. This carrier redistribution can significantly modify the ratio of the gains for different polarizations, in particular, decreasing the TM gain with respect to the TE gain, and, hence, is an important design consideration. We use our model and experimental data to explore design criteria for 1550-nm polarization-independent SOA´s.