Large-mode-volume transverse-electric-polarized distributed feedback cavity on silicon-on-insulator

We demonstrate a large-mode-volume transverse-electric-polarized λ∕4 shifted distributed feedback(DFB) cavity on silicon-on-insulator(SOI). A 2.86 mm-long DFB cavity with sidewall corrugation on the ridge is fabricated on a silicon rib waveguide. The cavity structure is designed to enlarge both the longitudinal and transversal mode profiles of the cavity to enclose more luminescent media. Design strategies are verified by both finite difference time domain simulation and experiments. A linewidth of 69 pm and an extinction ratio of 15 d B is obtained,indicating not only the well confinement of the longitudinal mode, but also its well stretching to the cavity ends.The mode volume is 75.39 μm3.