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

An erbium-doped microlaser is demonstrated utilizing SiO microdisk resonators on a silicon chip. Passive microdisk resonators exhibit whispering-gallery-type modes (WGM's) with intrinsic optical quality factors of up to 6x10⁷ and were doped with trivalent erbium ions (peak concentration ~3.8x10²⁰ 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 ⁴/15/2-->⁴/13/2 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 µW and allowed measuring the spontaneous emission coupling factor: β ≈1x10^-3.