Weighted-coupling Y-branch optical switch in InGaAs/InGaAlAs quantum well electron transfer waveguides

We demonstrate the first weighted-coupling Y-branch switch in semiconductors. The active waveguide core contains an InGaAs/InGaAlAs chopped quantum well electron transfer structure which provides large voltage-controlled refractive index changes near 1.55 μm with high speed capability. We obtain polarization-independent switching over a wide operating range, from 1.52 to 1.58 μm wavelength. We show that shaping the Y-branch results in significant improvements in voltage-length product and crosstalk performance over conventional, non-shaped Y-branches. In push-pull configuration, the drive voltage requirement is only 3.5 V for a 550 μm active length switch.