Amplifying characteristics of 1.55-μm polarization-insensitive SOAs with MQW and strained-bulk active layers for device application

Fundamental amplifying characteristics of 1.55-μm semiconductor optical amplifiers (SOAs) that contain multiquantum well (MQW) active layers with an optimized tensile strain or bulk active layers with various tensile strains were investigated. Both types of SOAs have their own merits and demerits. For device application in networks, driving current and wavelength in the low-polarization-sensitivity condition are very important, but they have not been clarified yet. The results of the present investigation clarify the driving current and wavelength characteristics of low-polarization-sensitivity SOAs with MQW and strained-bulk active layers. The low-polarization-sensitivity condition of SOAs with a strained-bulk active layer is shown to have a very wide range of driving current and wavelength for network-device application. These results, with other requirements taken into account, provide guidelines for choosing the type of SOA most suitable for a given application.