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

An erbium-doped microlaser is demonstrated utilizing SiO₂ microdisk resonators on a silicon chip. Passive microdisk resonators exhibit whispering-gallery-type modes (WGM's) with intrinsic optical quality factors of up to 6×10⁷ and were doped with trivalent erbium ions (peak concentration ~3.8×10²⁰0.3em0excm^-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 ⁴I15∕2→⁴I13∕2 erbium transition at 14500.3em0exnm, 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 430.3em0exμW and allowed measuring the spontaneous emission coupling factor: β≈1×10^-3.