Low-voltage interferometric modulator in zinc-diffused strontium barium niobate (SBN:60)

Optical waveguides have been produced in Z-cut Sr0.6Ba0.4Nb2O6 (SBN:6O) by zinc diffusion from vapor phase at 1000 °C for 30 min. Values of 7.3 μm for the diffusion depth and a surface concentration of 4.2×1020 cm −3 for Zn were obtained from an electron microprobe analysis. Electro-optic modulation at 0.83 μm wavelength has been demonstrated on a Mach–Zehnder interferometer produced by this diffusion technique. An extinction ratio of 78% and a voltage-length (VL) product of 0.48 V cm for a TM polarized input light were obtained. Prism coupler measurements on planar waveguides diffused at 800 °C for 6 h have shown an effective index increase of 0.025 for the fundamental mode in both TE and TM polarization.