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.