Polarization-insensitive SOA with a strained bulk active layer for network device application

Current and wavelength characteristics for 1.55-μm semiconductor optical amplifiers (SOAs) containing bulk active layers with various tensile strains were investigated. The strain dependence of the gain-difference between the TE-mode and TM-mode (/spl Delta/G/sub TE-TM/) was almost linear having a waveguide-width over 0.8-1.5 μm. A -0.12% tensile-strained bulk SOA had very low /spl Delta/G/sub TE-TM/ of less than 0.8 dB for driving current ranging from 0 to 120 mA. The low-polarization-sensitive condition of SOAs with strained-bulk active layers was shown to yield very wide range in driving current and wavelength for network device applications.