1.55 mu m polarization-insensitive high-gain tensile-strained-barrier MQW optical amplifier

A polarization-insensitive semiconductor optical amplifier was realized at a wavelength of 1.55 mu m. The active layer consisted of a tensile-strained-barrier multiple quantum well (MQW) structure. At a driving current of 150 mA, no dependence of the saturation characteristics on modes was obtained. The saturation output power at which the gain decreases 3 dB is 13.3 dBm. A slightly higher saturation output power of 14 dBm was measured at a driving current of 200 mA. No large difference was observed between transverse-electric (TE) and transverse-magnetic (TM) modes. A high gain of 27.5 dB at a polarization sensitivity of 0.5 dB and a high saturation output of 14 dBm were realized simultaneously by using a longer device with reduced residual facet reflectivities.< >