Fabrication, operation, and applications of efficient dielectric waveguide lasers

This paper reviews our recent results on rare-earth-ion-doped integrated lasers. We have concentrated our efforts on crystalline potassium double tungstates and amorphous aluminum oxide. In the former material class we have demonstrated channel waveguide lasers based on Yb3+ doping, operating near 1 µm wavelength with slope efficiencies exceeding 70% and output powers up to 418 mW, as well as a record-low quantum defect of 0.7%. When activating with Tm3+, we have achieved lasers operating near 2 µm wavelength with a slope efficiency of 70% and 300 mW output power, which are currently tested for trace-gas sensing of NH3 and CO2. In Al2O3 layers on silicon wafers, when doped with Er3+, we have demonstrated a distributed-feedback channel waveguide laser at 1.5 µm wavelength with a free-running line width of 1.7 kHz. Yb3+ doping has resulted in distributed-feedback and distributed-Bragg-reflector channel waveguide lasers with 67% slope efficiency and up to 55 mW output power. Dual-wavelength lasers have been demonstrated with this approach and a stable microwave signal at 15 GHz has been generated via heterodyne detection, which has then been used as a simple read-out for intra-laser-cavity optical sensing of nanoparticles in these lasers.