According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-opt...According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-optic low coherence interferometer in Michelson configuration. The wave front of the reflected light beam is well enough to form an interferogram with a beam reflected from an optic mirror mounted on a stepping scanning-motor. The central peak of the interferogram is read as a measure of the liquid level. Experimental results show that this noncontact method can reach a resolution of ±1.25 μm in the measurement range of 86 mm.展开更多
We propose and demonstrate an all-fiber liquid-level sensor using an in-line multimode-single-mode-multimode (MSM) fiber structure. A piece of single-mode fiber (SMF) is spliced to two sections of equivalent multimode...We propose and demonstrate an all-fiber liquid-level sensor using an in-line multimode-single-mode-multimode (MSM) fiber structure. A piece of single-mode fiber (SMF) is spliced to two sections of equivalent multimode fiber (MMF) which are used as both mode splitter and mode coupler. The cladding mode will be excited when the light propagates from MMF to SMF, and then it will be combined with fundamental mode to form a Mach-Zehnder interferometer (MZI) when the light propagates from SMF to the other MMF. The liquid level is detected by the selected resonant dips shift of the transmission spectrum. A sensing sensitivity of 264.6 pm/mm is achieved for the proposed sensor with an SMF length of 26mm. Due to its compact structure, easy fabrication, and high sensitivity, the proposed liquid-level sensor is attractive for practical applications in a variety of fields, such as marine detection and chemical processing.展开更多
An optic-fiber liquid-level sensor based on tapered chirped grating was proposed and demonstrated experimentally.With a properly designed column buoy hung to chain wheel,the liquid-level variation was converted to axi...An optic-fiber liquid-level sensor based on tapered chirped grating was proposed and demonstrated experimentally.With a properly designed column buoy hung to chain wheel,the liquid-level variation was converted to axial strain,which made the reflection spectrum of the tapered chirped grating narrowed or broadened correspondingly.And a high-sensitive liquid-level sensor was obtained by monitoring the bandwidth variation of the tapered chirped grating.Compared with traditional absolute wavelength or power detection,this special monitoring technique based on bandwidth modulation makes the liquid-level sensor insensitive to spatially uniform temperature variations and power fluctuations from down-lead or light source.展开更多
基金Dalian Science and Technology Foundation and National Science Foundation(30470416)
文摘According to the fact that the surface of liquid with low viscosity coefficient is a good reflection plane for a broadband light beam, liquid-level measurement in micrometer resolution is designed based on a fiber-optic low coherence interferometer in Michelson configuration. The wave front of the reflected light beam is well enough to form an interferogram with a beam reflected from an optic mirror mounted on a stepping scanning-motor. The central peak of the interferogram is read as a measure of the liquid level. Experimental results show that this noncontact method can reach a resolution of ±1.25 μm in the measurement range of 86 mm.
基金This study was supported in part by the National Natural Science Foundation of China (NSFC) (Grant Nos. 61727816, 61520106013, and 61705031)in part by China Postdoctoral Science Foundation (Grant Nos. 2017M610175 and 2018T110216)in part by Fundamental Research Funds for Central Universities (Grant No. DUT19LAB32) Sponsor, and financial support acknowledgments are placed here.
文摘We propose and demonstrate an all-fiber liquid-level sensor using an in-line multimode-single-mode-multimode (MSM) fiber structure. A piece of single-mode fiber (SMF) is spliced to two sections of equivalent multimode fiber (MMF) which are used as both mode splitter and mode coupler. The cladding mode will be excited when the light propagates from MMF to SMF, and then it will be combined with fundamental mode to form a Mach-Zehnder interferometer (MZI) when the light propagates from SMF to the other MMF. The liquid level is detected by the selected resonant dips shift of the transmission spectrum. A sensing sensitivity of 264.6 pm/mm is achieved for the proposed sensor with an SMF length of 26mm. Due to its compact structure, easy fabrication, and high sensitivity, the proposed liquid-level sensor is attractive for practical applications in a variety of fields, such as marine detection and chemical processing.
基金supported by the National Natural Science Foundation of China (Grant No. 61007007)the Fundation of BeiJing Municipal Committee of CPC Organization Department (Grant No. 2012D005002-000001)
文摘An optic-fiber liquid-level sensor based on tapered chirped grating was proposed and demonstrated experimentally.With a properly designed column buoy hung to chain wheel,the liquid-level variation was converted to axial strain,which made the reflection spectrum of the tapered chirped grating narrowed or broadened correspondingly.And a high-sensitive liquid-level sensor was obtained by monitoring the bandwidth variation of the tapered chirped grating.Compared with traditional absolute wavelength or power detection,this special monitoring technique based on bandwidth modulation makes the liquid-level sensor insensitive to spatially uniform temperature variations and power fluctuations from down-lead or light source.
