MEMS Processing Technology And Heat Treatment On High-Q Optical Toroidal-cavity

Ultra-high quality factor optical micro-resonators with Whispering Gallery Mode (WGM) and small mode volume become powerful tools to explore non-linear optics and cavity quantum electrodynamics(CQED). There are also potential applications in optical integration, optical network, optical quantum entanglement computing and other information field. The main optical micro-resonators include microspheres, pillar microcavities and the planar microcavities (planar microdisks and planar microtoroids). This paper will focus on the study of planar microcavities. Using the MEMS processing technology, we have designed and fabricated high-Q value planar microcavities and toroidal-cavity. Then we build a coupling system and test the quality factors. The main contents and key points of this thesis are as follows:1. Choose silica material to fabricate the planar microcavities. Firstly 2-micron thick SiO2 layer was thermally grown on (100) silicon crystal surface, and then photoresist painting, exposure, and a variety of etching; For etching the silica dioxide layer we use wet etching(HF/H2O solution) and dry etching (reactive ion beam etching) respectively; For etching silicon column we use ICP etching system and XeF2 etching system. Secondly use lithography and etching methods to produce planar microdisks.2. After the prepare the microdisk cavity, we use the theory that hydrogen flame melt the optical fiber to prepare the microsphere cavity to establish physical model of the microcavity. Infer the temperature of the surface of the cavity and use the ANSYS software to analysis the thermal simulation.3. Based on the above theoretical analysis of thermal simulation, using Diamond K-500 type carbon dioxide laser and pulsed sealed-off CO2 laser to established the laser reflow system。After reflow the micro-disk, Raman thermal -stress were tested on the micro-cavity. Finally we got the best of laser processing power and thermal stress. 4. Build the coupling system. Firstly with brief description of coupled systems theory and the effects analysis of the system Q value, Secondly use the coupling system and AFM system to test planar microdisks and planar microtoroids, the results show that the reflow process by laser reduces the surface roughness of cavity at the same time improve the quality factor.