Demonstration of an erbium-doped microdisk laser on a silicon chip

Abstract

An erbium-doped microlaser is demonstrated utilizing $\mathrm{Si}{\mathrm{O}}_{2}$ microdisk resonators on a silicon chip. Passive microdisk resonators exhibit whispering-gallery-type modes (WGM's) with intrinsic optical quality factors of up to $6\ifmmode\times\else\texttimes\fi{}{10}^{7}$ and were doped with trivalent erbium ions (peak concentration $\ensuremath{\sim}3.8\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$) using MeV ion implantation. Coupling to the fundamental WGM of the microdisk resonator was achieved by using a tapered optical fiber. Upon pumping of the $^{4}I_{15∕2}\ensuremath{\rightarrow}^{4}I_{13∕2}$ erbium transition at $1450\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$, a gradual transition from spontaneous to stimulated emission was observed in the $1550\text{\ensuremath{-}}\mathrm{nm}$ band. Analysis of the pump-output power relation yielded a pump threshold of $43\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{W}$ and allowed measuring the spontaneous emission coupling factor: $\ensuremath{\beta}\ensuremath{\approx}1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$.