Integrated electro-optic Mach-Zehnder switch realized by Zinc in-diffuision

We demonstrate the use of an area selective zinc in-diffusion technique to fabricate an integrated InP/InGaAsP MachZehnder optical switch. The zinc in-diffusion process using a semi-sealed open-tube diffusion furnace was characterized to enable the creation of p-n junctions at a precise depth in selected areas of the device sample. The method is simple, yet highly controllable and reproducible; with the crystal quality remaining intact after the diffusion process is complete. Using this technique an integrated 1x2 Mach-Zehnder optical switch has been fabricated. Our preliminary devices show a switch contrast ratio of 12 dB with a voltage swing of +/-2.5 volts. Improving our fabrication process will further optimize the performance of the switch. Nevertheless, very good electrical isolation is obtained between the contacts, which demonstrates the potential of the technique for the fabrication of Photonic Integrated Circuits.