High-Q optical resonators in silicon-on-insulator-based slot waveguides

Abstract

This letter describes the design, fabrication and characterization of high-Q oval resonators based on slot waveguide geometries in thin silicon-on-insulator material. Optical quality factors of up to 27 000 were measured in such filters, and we estimate losses of Ϫ10 dB/cm in the slotted waveguides on the basis of our resonator measurements. Such waveguides enable the concentration of light to very high optical fields within nanoscale dimensions, and show promise for the confinement of light in low-index material with potential applications for optical modulation, nonlinear optics and optical sensing.

Low-Loss Slot Waveguides with Silicon (111) Surfaces Realized Using Anisotropic Wet Etching

“…Since the light is more confined in the slot region, any surface roughness, introduced during the fabrication process, causes significant scattering loss. Therefore, fabrication of low-loss slot waveguides is challenging and the lowest reported propagation loss was 10 dB/cm (Baehr-Jones et al, 2005), from a standard vertical slot waveguide. There are different approaches proposed in the literature to reduce this propagation loss.…”

Optimal Design of a Silicon-on-Insulator Nanowire Waveguide for Broadband Wavelength Conversion

“…And then SOI waveguide-based high-Q microring resonators were also introduced in order to increase the conversion efficiency and decrease the pump power [17,18]. The efficiency is tightly related to the effective mode area of the waveguide and some new structures such as slot waveguides [19,20] and surface plasmon waveguides [21] have exhibited the ability to confine light. In addition, the dispersion of the SOI waveguides has been demonstrated to be governed by its shape and dimensions [22,23], which provides the option to realize broadband wavelength conversion by tuning the dispersion characteristics of silicon nanowire waveguides [24].…”

Chemical Sensors Based on Photonic Structures

“…However, etching in a very narrow region (slot region width g ~ 20-100nm) can produce large roughness in the vertical interface. By this way, in vertical slot waveguides, where the E x -field is concentrated at the interface between the high and low refractive index region, propagation losses can be very high, such as 11.6 ± 3.6 dB/cm in a single slot of 50nm (Baehr-Jones et al, 2005). This problem can be partially solved by using horizontal slot waveguides ( Fig.…”