Achieving Higher Modulation Efficiency in Electrooptic Polymer Modulator With Slotted Silicon Waveguide

Journal of Lightwave Technology (Impact Factor: 2.86). 12/2011; DOI: 10.1109/JLT.2011.2168385
Source: IEEE Xplore

ABSTRACT Silicon slot waveguide based Mach-Zehnder interferometric modulators with electrooptic polymers in the slot have the advantage of low half-wave voltage-length product (Vπ *L). Several key aspects of this unconventional electrooptic polymer modulator design to optimize the modulator performance are studied in this work. Both computer simulation and experiments have been conducted to understand the relationship between modulator performance such as modulation efficiency, optical loss and the waveguide design parameters. Techniques to achieve efficient poling of electrooptic polymers in the silicon slot waveguide have been developed. The doping of the silicon to enhance conductivity for efficient poling and the trade-off between conductivity and optical loss are experimentally investigated. Surface passivation of silicon nanophotonic structures has been found to be effective in improving poling efficiency. By applying these techniques to a silicon slot waveguide Mach-Zehnder modulator, a low Vπ*L of 0.52 V ·cm has been achieved. Finally travelling wave electrode designs have been evaluated and the results show that the bandwidth is mainly limited by the attenuation of the radio frequency signal in the electrode and a standard coplanar waveguide electrode design is able to reach 20 GHz in modulators of silicon slot waveguide embedded in electrooptic polymer.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Because of stronger optical confinement density, silicon slot waveguides tend to have higher scattering loss than normal ridge waveguides with same sidewall roughness. A wet chemical process is found to be highly effective in reducing the surface roughness and scattering loss. A reduction in scattering loss by 10.2 dB/cm for TE and 8.5 dB/cm for TM polarizations has been achieved.
    Optics Letters 01/2012; 37(1):13-5. · 3.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This review summarizes recent development of highly efficient organic electricoptic (OEO) materials and their applications in hybrid photonic devices. New generation of highly efficient EO polymers possessing large Pockels coefficients of 200-250 pm/V at 1.3 μm and excellent thermal and photochemical stability have been developed for advanced photonic devices. In addition, new pyroelectric poling process provides an efficient and reliable high field poling for EO polymers in multilayered thin films and nanophotonic waveguides. Using OEO materials as a key enabling element, significant progress has been made in the development of innovative hybrid EO devices, including EO polymer hybrid nanophotonic waveguides with high-index semiconductors, all polymer- and polymer/sol-gel-based EO modulators using low-refractive-index cladding layers, and EO polymer-based electric field sensors. At the end, this review also provides an outlook of future development of OEO materials and their hybrid systems for advanced photonic technologies.
    IEEE Journal of Selected Topics in Quantum Electronics 01/2013; 19(6):42-53. · 3.47 Impact Factor