The Fabrication And Optical Character Research Of Erbium-Dopped Microsphere

Erbium is one of Rare earth elements.It emits light around a wavelength of 1.55μm when 4I(13/2)-4I(15/2)level trasistion happens.This wave-band according to communication band of C and the minimum absorption window for fiber. Erbium-dopped optical cavity, its dimension is 5～500μm with the character of lower nonlinear threshold, Ultral-high Q and smaller model volume.It becomes one of the research hotspot in the field of low-threshold laser, High sensitivity sensor, on-chip-scale light source and so on.In this master's thesis, fusion method is used to process Erbium-dopped microsphere. CO2 laser with the wavelength of 10.6μm melt the Erbium-dopped fiber and the processing time and temperature is controlled through modulating the laser pulse. Laser converges upon tip of Erbium-dopped fiber according to light path designed by gilt-total-reflection-mirror.By controlling the laser pulse and monitoring the change of fiber thtough CCD, we stop the pulse at appropriate time and microsphere formed by its own surface tension.Then we tested the fluorescence and near-field coupling of Erbium-dopped microsphere. We chose the wavelength of 980nm and 1480nm lasers as pumps according to energy level transistion and abtained the resonat spectrum of Erbium-dopped microsphere. Taper-fiber coupled evanescent-wave light into microsphere and has higher coupling efficiency. We abtained the resonat spectrum of Erbium-dopped microsphere through changing the coupling gap.Through comparing the experiment results to the theoretic analysis, we verified the spectrum of Erbium energy level transistion. We summaried affecting factors for the further research and did ground-research to a non-degenerate optical parametric process of frequency comb. It also promotes high-sensitivity sensors, laser gyro, on-chip-scale light source and other fields.