title: Ultracompact 1×4 TM-polarized beam splitter based on photonic crystal surface mode.
abstract: We provide an improved surface-mode photonic crystal (PhC) T-junction waveguide, combine it with an improved PhC bandgap T-junction waveguide, and then provide an ultracompact 1×4 TM-polarized beam splitter. The energy is split equally into the four output waveguides. The maximal transmission ratio of each output waveguide branch equals 24.7%, and the corresponding total transmission ratio of the ultracompact 1×4 beam splitter equals 98.8%. The normalized frequency of maximal transmission ratio is 0.397(2πc/a), and the bandwidth of the ultracompact 1×4 TM-polarized beam splitter is 0.0106(2πc/a). To the best of our knowledge, this is the first time such a high-efficiency 1×4 beam splitter exploiting the nonradiative surface mode as a guided mode has been proposed. Although we only employed a 1×4 beam splitter, our design can easily be extended to other 1×n beam splitters.
authors.affiliation: Nano-optoelectronics Laboratory, Institute of Semiconductors, CAS, Beijing 100083, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Jiang
authors.forename: Yejin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yufei
authors.initials: Y
authors.lastname: Wang
authors.forename: Anjin
authors.initials: A
authors.lastname: Liu
authors.forename: Wanhua
authors.initials: W
authors.lastname: Zheng