Confined one-way mode at magnetic domain wall for broadband   high-efficiency one-way waveguide, splitter and bender
  We find the one-way mode can be well-confined at the magnetic domain wall by the photonic bandgap of gyromagnetic bulk material. Utilizing the well-confined one-way mode at the domain wall, we demonstrate the photonic one-way waveguide, splitter and bender can be realized with simple structures, which are predicted to be high-efficiency, broadband, frequency-independent, reflection-free, crosstalk-proof and robustness against disorder. Additionally, we find that the splitter and bender in our proposal can be transformed into each other with magnetic control, which may have great potential applications in all photonic integrated circuit. 
Xiaogang Zhang, Wei Li, and Xunya Jiang
cond-mat.mes-hall physics.optics