All optical modulation of whispering-gallery-mode optical micro-cavities with Raman gain

Based on the high demand for all optical control and all optical switches in optical communication network, the Raman gain induced resonance control of whispering-gallery-mode optical micro-cavities was investigated theoretically and experimentally. Theoretical analysis shows that Raman gain can compensate cavity loss and change the coupling regime of micro-cavities system. As a result on-resonance transmission in the micro-cavities system can be controlled without any mechanical movement. In experiment fiber taper coupled silica micro-toroid system was studied. Raman gain was pumped with an ultra-low pump power of 560W, with this Raman gain the fiber taper coupled micro-cavity system was turned from deep under coupling regime to critical coupling regime and the on-resonance transmission of the 1 545.7 nm signal light was turned down by 13.5 dB.