On-chip integrated lasers in Al2O3:Er on silicon

Erbium-doped aluminum oxide channel waveguides were fabricated on silicon substrates and their characteristics were investigated for Er concentrations ranging from 0.27 to 4.2 × 10 cm. Background losses below 0.3 dB/cm at 1320 nm were measured. For optimum Er concentrations in the range of 1 to 2 × 10 cm, internal net gain was obtained over a wavelength range of 80 nm (1500-1580 nm) and a peak gain of 2.0 dB/cm was measured at 1533 nm. Integrated Al2O3:Er channel waveguide ring lasers were realized based on such waveguides. Output powers of up to 9.5 μW and slope efficiencies of up to 0.11 % were measured. Lasing was observed for a threshold diode-pump power as low as 6.4 mW. Wavelength selection in the range 1530 to 1557 nm was demonstrated by varying the length of the output coupler from the ring.