Surface-normal electro-optic-polymer modulator with silicon subwavelength grating

We propose novel silicon-based surface-normal optical modulator using electro-optic (EO) polymer. The EO polymer is embedded inside a thin silicon subwavelength grating layer, which is used as both the interdigitated electrodes for effective poling of the EO polymer, and as high-Q resonant structure for the incident light to enable efficient modulation. We numerically demonstrate 10-dB intensity modulation at 1550-nm wavelength under a refractive index change of only 3.8 × 10−4, corresponding to the driving voltage below 1V. Total-reflectance phase modulator is also demonstrated by adding a backside reflector. With inherently high-speed response over several tens of GHz, scalability to dense 2-D array integrated with CMOS driver circuitry, and relatively easy and low-cost fabrication without epitaxial process, the proposed device may find versatile applications in optical interconnects, free-space optical communications, imaging and sensing.