An asymmetrical tapered singlemode–multimode–singlemode(SMS)fiber coupler based on two parallel physical contact SMS fiber structures was proposed.Since the coupler includes modes both from fiber core and cladding,t...An asymmetrical tapered singlemode–multimode–singlemode(SMS)fiber coupler based on two parallel physical contact SMS fiber structures was proposed.Since the coupler includes modes both from fiber core and cladding,two dips of the transmission spectrum exhibit different sensing characteristics to the surrounding temperature and refractive index(RI)change,which allows the use of the standard matrix inversion method to determine temperature and RI simultaneously.The temperature sensitivities of 0.0498 and 0.0324 nm/℃ and RI sensitivities of 1151.76 and 1325.66 nm/RIU have been achieved,respectively.For biosensing application,with the functionalized fiber coupler sensor,a human chorionic gonadotropin concentration of 0.05 mIU/mL has been detected for a wavelength shift of 0.2 nm with good stability and excellent selectivity.The developed tapered SMS fiber coupler structure has advantages of simultaneous measurement of two independent parameters,simple configuration,low cost,and good repeatability that offer a great potential for medical diagnostics.展开更多
基金This work was supported by the National Natural Science Foundations of China(Nos.61665007 and 11864025)the Natural Science Foundation of Jiangxi(Nos.20192ACBL21051 and 20172BCB22012)Key Projects of Basic Research and Applied Research in Universities in Guangdong Province(No.2018KZDXM067).
文摘An asymmetrical tapered singlemode–multimode–singlemode(SMS)fiber coupler based on two parallel physical contact SMS fiber structures was proposed.Since the coupler includes modes both from fiber core and cladding,two dips of the transmission spectrum exhibit different sensing characteristics to the surrounding temperature and refractive index(RI)change,which allows the use of the standard matrix inversion method to determine temperature and RI simultaneously.The temperature sensitivities of 0.0498 and 0.0324 nm/℃ and RI sensitivities of 1151.76 and 1325.66 nm/RIU have been achieved,respectively.For biosensing application,with the functionalized fiber coupler sensor,a human chorionic gonadotropin concentration of 0.05 mIU/mL has been detected for a wavelength shift of 0.2 nm with good stability and excellent selectivity.The developed tapered SMS fiber coupler structure has advantages of simultaneous measurement of two independent parameters,simple configuration,low cost,and good repeatability that offer a great potential for medical diagnostics.
