| Arc discharge technique is a low-cost and high-performance method for optical fiber sensor preparation.The pressure-assisted arc discharge technique is the latest development stage of the technology.The pressure-assisted arc discharge of a glass tube with a size of a hundred microns will have an expansion effect and form a hollow thin film structure,which is of great value in the preparation of optical fiber Fabry-Perot sensors and Whispery Gallery mode(WGM)micro-cavity sensors.In order to meet the demand of high sensitivity pressure detection,by improving the key technology of the expansion assisted discharge method,in this paper two kinds of ultrathin and symmetrical micro-bubbles with the thickness of 2?m are prepared,and a kind of integrated and highly sensitive optical fiber Fabry-Perot pressure sensor is obtained by embedding micro-bubbles in the optical fiber.The WGM quality factor and pressure sensing characteristics of microbubble microcavity are obtained by combining cone fiber and whispering wall microcavity test platform.The research content has certain reference value for developing related pressure sensors.The main works of this paper have been completed:The pressure detection principle of microbubble structure optical fiber Fabry-Perot pressure sensor and micro bubble WGM microcavity is theoretically analyzed.A fiber Fabry-Perot pressure sensor with fiber embedded microbubble structure is designed and fabricated.The preparation method of the sensor is improved.The pressure and temperature sensing characteristics of the sensor are studied.The pressure sensing characteristics of the sensor are simulated and explained with the ANSYS.The method of microbubble WGM microcavity preparation,quality factor,pressure sensing characteristics and FDTD software were studied,and the influence of the size of microbubbles on the characteristics of WGM microcavity was analyzed.The main conclusions of this paper include:1.A optic fiber Fabry-Perot pressure sensor with the wall thickness of 2?m is fabricated and its characteristics are analyzed in this paper,the pressure sensitivity is as high as164.55pm/KPa and the temperature sensitivity is only 4 pm/?.It shows that the sensor not only has high sensitivity to pressure sensing,but also has a good ability to resist temperature interference.2.Combining with ANSYS,the high sensitivity pressure characteristics of the sensor are theoretically analyzed and explained.It is found that when the pressure increases from 92KPa to 100KPa,the cavity length deformation of fiber-tip microbubble is 0.06pm,and the pressure sensitivity of the residual air inside the cavity is 0.01pm/KPa.3.The preparation and characteristics tests of microbubble WGM microcavity are completed,obtained the quality factor characteristics of 10~7 grades,and analyzed the pressure sensing effect.At the same time,using FDTD to study the effect of the variation of microcavity parameters and coupling distance on the quality factor of microcavity,and the above experimental results were are explained. |
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