Electro-optic modulation in bulk silicon using surface plasmon resonance

•We propose a new optical modulator design for silicon photonics technology.•Use of surface plasmon mode allows us to realize optical modulator in bulk silicon.•This design allows an easy route to integrate electronic and photonic components on the same platform.•In this design we also take advantage of high spectral sensitivity of the surface plamson resonance.•For 0.02 change in refractive index, we achieved 100 nm spectral shift with a modulation depth of 10 dB.

We propose and present simulated results for a new design of an optical modulator based on Surface Plasmon Polariton (SPP) resonance. The modulator is realized on a bulk silicon substrate, thus offering an opportunity for front-end integration with electronic circuits. The device consists of a dielectric waveguide evanescently coupled to a SPP mode at the interface between bulk silicon and metal. By using SPP resonance we achieved an ultra-high spectral sensitivity (∼5000 nm/refractive index unit) with large modulation bandwidth (90 nm). For a refractive index change of 0.02, we achieved 100 nm shift in resonance wavelength and a modulation depth of ∼10 dB.