| Optical fiber fluorescent temperature sensing is a new sensing technology, which is based on optical fiber and fluorescence temperature sensing. Compared with the conventional temperature sensing, it has lots of the advantages, such as high sensitivity and resolution, interference, easy to disposal and installation, anti-electromagnetic and long service life. It can also realize accurate temperature detection in strong electromagnetic fields, and any other harsh environment with explosive, high temperature and high pressure. Therefore, optical fiber fluorescent temperature sensors have broad application prospect in the power system, industrial production, aerospace, biological medical and other fields.Microstructured optical fibers(MOFs) have unique optical waveguide characteristics, and their structure can also be designed to realize your special purposes. More fiber sensor production methods are discovered because of MOFs' appearance. The relationship of optical fiber and other sensing material becomes much closer. Especially for hollow-core MOFs(HC-MOFs), sensing materials are filled in its large air holes, which can effectively enhance the interaction between light and materials.In this paper, quantum dots materials were filled in the air holes of Simplified hollow-core microstructured optical fiber(SHC-MOF), and a fluorescent temperature sensor was produced after encapsulated. The multi-parameter of fluorescence which includes peak wavelength, peak intensity and FWHM are sensitive to temperature. Multi-parameter fluorescence characteristics of the temperature sensor were conducted in-depth research and analysis. The main work is given as follows:1. A manufacturing method of all-fiber liquid-core MOF is proposed. First of all, femtosecond laser carves a channel on the end-face of the multi-mode fiber(MMF), which is used for filling after fusion splicing the SHC-MOF and the MMF. After filling liquid, adhesive contained in a quartz groove seal the channel to prevent evaporation of the liquid. After curing the adhesive in the groove, a compact all-fiber liquid-core MOF is done already. Previous long-term stability test at room temperature indicates that the characteristic of Liquid-core SHC-MOF made by the above method filling aqueous quantum dots solution is very stable. The fluorescence temperature sensor is done for measuring temperature. The obtained temperature sensitivities dependence of fluorescence peak wavelength and peak intensity is 163.5 pm/oC and 11.25 counts/oC, respectively. And its temperature sensitivity of peak wavelength is ~13 magnitude larger than the traditional fiber Bragg gratings.2. In order to further decrease the fluidity of the aqueous quantum dots solution, the mixture of aqueous quantum dots solution and UV glue is filled in the SHC-MOF. A reflecting temperature probe is manufactured after curing. The obtained temperature sensitivities dependence of fluorescence peak wavelength and peak intensity are 107.5 pm/oC and 6.17 counts/oC, respectively. Compared with directly filling aqueous quantum dots solution, the linearity is significantly higher. Repeatability and stability of the temperature probe has also been greatly improved.3. Preparation method of liquid-core optical fiber is really complex. Liquid-core optical fiber is difficultly made into end product, and its stability needs to be improved. Therefore, the mixture of colloidal quantum dots and UV glue is filled in the SHC-MOF. After curing, the temperature sensor is made. Temperature variation dependence of self-reference fluorescence intensity has a good repeatability. In the temperature range of-10 oC ~ 50 oC, the fluorescence peak wavelength, the self-reference fluorescence intensity and FWHM vary repeatedly with temperature, and showed good linear relationships. And the corresponding temperature sensitivities are 91.1 pm/oC,-0.0041 /oC and 47 pm/oC, respectively. Multi parameters of the sensor are sensitive to the measured temperature, which is beneficial to improve the accuracy of temperature detection. |
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