Demonstration of an erbium doped microdisk laser on a silicon chip

An erbium doped micro-laser is demonstrated utilizing $mathrm{SiO_{2}}$ microdisk resonators on a silicon chip. Passive microdisk resonators exhibit whispering gallery type (WGM) modes with intrinsic optical quality factors of up to $6times{10^{7}}$ and were doped with trivalent erbium ions (peak concentration $mathrm{sim3.8times{10^{20}cm^{-3})}}$ 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 $^{4}% I_{15/2}longrightarrow$ $^{4}I_{13/2}$ erbium transition at 1450 nm, a gradual transition from spontaneous to stimulated emission was observed in the 1550 nm band. Analysis of the pump-output power relation yielded a pump threshold of 43 $mathrm{mu}$W and allowed measuring the spontaneous emission coupling factor: $betaapprox1times10^{-3}$.