题    目：Miniaturized fiber-optic interferometers for micro-sensing applications
报告人：Prof. Nan-Kuang Chen（陈南光教授）（台湾国立联合大学光电工程系）
主持人：关柏鸥教授
时    间：2012年11月20日（星期二）下午14: 30-16:00
地    点：曾宪梓科学馆四楼405会议室

报告摘要：
The fiber abrupt tapering technique is the fabrication method which breaks the adiabatic waveguiding in fiber core and transforms fractional power of the core mode into cladding modes for making miniaturized fiber components. By introducing two adjacent abrupt tapers in a highly Er/Yb codoped silica fiber using a focused CO2 laser beam to make micro Mach-Zehnder interferometer (MZI), the minimum device length achieved can be as short as 180 um. Fractional power of the core mode is coupled to excite the cladding modes through the first abrupt taper and the residual core mode and the excited cladding modes thus propagate through the different optical paths. The cladding modes and the core mode meet up at the second abrupt taper to produce interferences. The cladding modes can sense the ambient index variations of the external material coating at the phase shifter or at the abrupt tapers. When the external material is coated at the abrupt taper, the mode jumping phenomena can be observed and a higher sensitivity can be achieved in contrast to the situation while the external material is coated surrounding the phase shifter. This micro MZI can be used to detect the micro index variation of 0.002 under a 6.3 picoliter of liquid volume. The corresponding resonant wavelength shift is 0.4 nm. This micro MZI had also been used to detect the concentration variations of glucose solution with a volume of 72 picoliter. Owing to the erbium and ytterbium ions doping in fiber core, the inversion rate is varied when the pump power is launched so that the optical absorption, dispersion and refractive index will be changed to adjust the resonant wavelengths accordingly. The micro MZI so made can be used to achieve phase modulators, pulsed fiber lasers, displacement and curvature sensors, pulse rate sensors, twist angle sensors, and other miniaturized sensing and communication components.

报告人简介：
Nan-Kuang Chen received the B. Sc. and M. Eng. degrees from the National Tsing Hua University, Taiwan, in 1996 and 1998, respectively, the Ph. D. degree from National Chiao Tung University, Taiwan, in 2006. During July 2006 to July 2007, he was a postdoctoral research fellow with the Department of Photonics, National Chiao Tung University, Taiwan. During August 2007 to July 2010, he was an Assistant Professor with the Department of Electro-Optical Engineering, National United University, Taiwan. He is currently an Associate Professor with the Department of Electro-Optical Engineering, National United University, Taiwan. He is also the Director of Optoelectronics Research Center, National United University, Taiwan, since August 2008. He was the visiting researcher in Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science for two months in 2009. He was also the visiting researcher in Department of Optical Engineering, Zhejiang University for half a month in 2010. From 2001, he has engaged in the field of fiber photonics and has authored and co-authored 120 international SCI journal and conference articles. He received the NUU Distinguished Research Award and NUU Outstanding Industrial Collaboration Award both in 2011 and in 2012. He is also the invited reviewers for the 19 SCI journals and the technical program committee members for several IEEE conferences. He has given invited talks at several international conferences and served as technical program chair for two international conferences. He holds 11 ROC patents, 11 US patents, 1 Korea patent, and 4 PRC patents. His research interests include dispersion engineering, fiber sensors, fiber-integrated devices, biophotonic sensors, high power fiber lasers, photonic micro/nanowire devices and resonators. Dr. Chen is a member of OSA and IEEE.

欢迎广大师生踊跃参加！

光子技术研究所
2012年11月15日