Beckmann, TobiasTobiasBeckmannBuse, KarstenKarstenBuseBreunig, IngoIngoBreunig2022-03-042022-03-042012https://publica.fraunhofer.de/handle/publica/23027210.1364/OL.37.005250Threshold and efficiency of optical parametric oscillation in whispering gallery resonators have been predicted to depend strongly on the coupling strength. Our experiments, varying the coupling strength continuously over 3 orders of magnitude, confirm these predictions. The pump threshold changes by a factor of 20, allowing the adaptation of the system to a wide range of input powers. The minimum threshold of 0.20 mW occurs for significant pump undercoupling. The efficiency increases monotonically with coupling, spanning 4 orders of magnitude with a maximum efficiency of 30% in contact yielding output powers exceeding 1 mW.enoptical resonatorslithium niobateparametric oscillators and amplifiersmicrocavity621535journal article