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Study On Wavelength Tuning Technology Of All-fiber Whispering Gallery Mode Resonator

Posted on:2019-09-10Degree:MasterType:Thesis
Country:ChinaCandidate:L G LiuFull Text:PDF
GTID:2428330566977026Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Whispering gallery mode resonator(WGMR)with ultrahigh quality factor and ultrasmall mode volume has been widely used in biochemical sensing,nonlinear optics and ultra-narrow band filtering.As an alternative of the filters with fixed wavelength,tunable optical fiber WGMR has great potentials in optical fiber sensing and communication systems.All fiber tunable WGMRs composed of microstructured fiber and ferrofluids with high thermo-optic efficiency are studied in this thesis,and the contents are as follows.(1)The eigen mode and mode coupling in the micro tube WGMR are firstly theoretically studied,providing guidelines for designing and optimizing the coupling state of the WGMR.Then,the principle of the laser aided thermo-optical tuning of the WGMR is analyzed in detail,which is helpful for studying the tuning of the WGMR.(2)A thermo-optically tunable all fiber WGMR based on hollow core fiber(HCF)and ferrofluids is proposed and fabricated.Heat is firstly generated in the ferrofluids by absorbing the pump light from a 980 nm laser diode and then transferred to the WGMR,resulting in changes in effective index of WGMs and thus resonant wavelength shift in the WGMR due to the thermo-optic effect.Experimental results show that the resonant wavelength shifts linearly with respect to the pump power,and the tuning efficiency and range of such a WGMR are respectively 39pm/mW and 4.138 nm.(3)In order to further improve the tuning efficiency,a grapefruit shaped photonic crystal fiber(PCF)based thermo-optically tunable WGMR is proposed and fabricated.The ferrofluid is firstly filled into the air holes of the PCF and then dried into ferroparticles,which increases the absorption area and decreases the tuning instability caused by the flowing of the ferrofluids.The tunability of the WGMR is studied by employing 980 nm and 1550 nm lasers as pump,respectively.Experimental results show that the resonant wavelength of the WGMR shifts linearly with the pump power.For the WGMR pumped by the 980 nm laser,the tuning efficiency and range are 162pm/mW and 4.31 nm,respectively.While the 1550 nm laser pumped WGMR has a tuning efficiency of 108pm/mW and a tuning range of 4.372 nm.The response time of the tunable WGMR is on the order of millisecond.
Keywords/Search Tags:Whispering Gallery Mode Resonator, Thermo-optic Tuning, Magnetic Fluid, Fiber Device
PDF Full Text Request
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