1.3-MU-M POLARIZATION-INSENSITIVE AMPLIFIERS WITH INTEGRATED-MODE TRANSFORMERS

We report for the first time polarization-insensitive, mixed-strain qu antum-well semiconductor optical amplifiers (QW SOA's) with monolithic ally integrated laterally tapered section for mode transformation. Thi s taper section improves coupling efficiency to cleaved single-mode fi bers by 3-4 dB compared to an untapered linear waveguide. We have demo nstrated 18-dB chip gain with less that l-dB polarization sensitivity of the gain. We also found that the output saturation power is about 1 0 dBm for all polarizations. The gain bandwidth was estimated to be 15 nm.