Integrated Al_2O_3:Er^3+ ring lasers on silicon with wide wavelength selectivity

Integrated Al(2)O(3):Er(3+) channel waveguide ring lasers were realized on thermally oxidized silicon substrates. High pump power coupling into and low laser output power coupling from the ring is achieved in a straightforward design. Output powers of up to 9.5 microW and slope efficiencies of up to 0.11% were measured while lasing was observed for a threshold diode-pump power as low as 6.4 mW for ring lasers with cavity lengths varying from 2.0 to 5.5 cm. Wavelength selection in the range 1530-1557 nm was demonstrated by varying the length of the output coupler from the ring.