Low-loss bent connections for optical switches

We present S-bent InP/InGaAsP rib waveguides used as connections for optical switches at /spl lambda/=1.5 /spl mu/m. Transitions between waveguides of different curvature and different lateral confinement are realized with adiabatic tapers. We investigated bends with radii from 200-1700 /spl mu/m and rib widths 2.2, 3.2, and 4.2 /spl mu/m. For rib width 3.2 /spl mu/m we obtain almost for all radii extremely small quasi-polarization independent excess-losses below 0.3 dB. The waveguides are easy to fabricate and the tapered transitions are tolerant to technological variations. The performance offers the chance of low cost and simple monolithic integration of large optical switch matrices in InP/InGaAsP.