title: Optical filter based on contra-directional waveguide coupling in a 2D photonic crystal with square lattice of dielectric rods.
abstract: A coupler-type optical filter in 2D photonic crystal (PhC) with square lattice of dielectric rods in air is presented. The reduced-index and increased-index waveguides of filter have dispersion curves with opposite slopes to realize contra-directional coupling, and the point of anti-crossing is designed below the light line to avoid vertical radiation. The filter has a broad operable bandwidth due to the absence of mini stop bands. The transmission properties are analyzed using coupled modes theory (CMT) and simulated using the finite-difference time-domain (FDTD) method. The results show that a filtering bandwidth of 4 nm can be achieved in the range of 1500~1600 nm, and over 83% drop coefficient is obtained.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Xu
authors.forename: Jiangang
authors.initials: J
authors.lastname: Wang
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: He
authors.forename: Liangcai
authors.initials: L
authors.lastname: Cao
authors.forename: Ping
authors.initials: P
authors.lastname: Su
authors.forename: Guofan
authors.initials: G
authors.lastname: Jin