1.3 /spl mu/m polarization insensitive tapered waveguide mode conversion structures with mixed quantum well active regions

Fiber alignment is an expensive stage in the packaging of semiconductor lasers and amplifiers. In order to reduce the cost, simpler fiber fixing and wider alignment tolerances are required. Polarization insensitive semiconductor amplifiers operating at 1.3 /spl mu/m and photonic integrated circuits made from them are of importance in present fiber optic systems. As a result, we have explored the incorporation of mode transformers in polarization insensitive amplifiers to reduce coupling losses and to ease alignment tolerances. We have employed a laterally tapered waveguide structure to achieve the spot-size conversion. This is an attractive approach because of the simple growth and fabrication processes involved and the possibility of integration in PICs with other devices. Another advantage is that the gain medium exists along the whole length of the device.