Abstract：The birefringence of photonic crystal fiber (PCF) is highly controllable by changing photonic crystal fiber structure and incident wavelength.  The two-core PCFs exhibit new coupling mechanism different from that in conventional waveguide couplers.  We report on the birefringence and guided-mode coupling properties of the PCFs.  Various PCF-based couplers, such as polarization dependent coupler, highly selective polarization coupler, nonreciprocal coupler, are presented.   

Changxi Yang’s biography:  Changxi Yang received the B. S. degree in physics from Nankai University, China, in 1986 and the Ph. D. degree in optics from the Institute of Physics, Chinese Academy of Sciences, Beijing in 1992.  From 1994 to 1995 he spent two years at University of California, Santa Barbara as a visiting researcher, working on photorefractive nonlinear optics. From 1999 to 2000 he spent one year at Bell Labs, Murray Hill, New Jersey as visiting researcher, working on optical phase conjugation. Now, he is a professor with the Department of Precision Instruments, Tsinghua University, Beijing.  He is the vice-director of the Institute of Opto-Electronic Engineering, Department of Precision Instruments, Tsinghua University. His research interests include photonic crystal fiber, ultra-short pulse frequency conversion, and polarization mode dispersion compensation.