In this paper, a compact all-optical five-channel demultiplexer (DEMUX) using 2D photonic crystal hexagonal cavities is proposed. The proposed DEMUX comprises bus/drop waveguides, photonic crystal waveguides containing four consecutive 120° bends, two power splitters, and hexagonal resonant cavities. By adjusting the radius and refractive index of the inner/coupling rods, position, and radius of the scattering rods, the operating wavelength and the output power of each port are managed. Normalized transmission spectra and calculations of band structure are calculated by the finite-difference time-domain (FDTD) and plane-wave expansion (PWE) methods, respectively. The resonant wavelengths of the proposed structure are 1328.7 nm, 1331.9 nm, 1335.4 nm, 1340.5 nm, and 1344.4 nm, respectively. Calculation results show that the average quality factor, optical transmission efficiency, passbands of channels, minimum and maximum crosstalk of nearly 6236, 95.98%, 0.22 nm, − 18.04 dB, and − 50.2 dB, respectively. The operating wavelength range of DEMUX is 1328 nm to 1345 nm and the average channel spacing between the channels nearly about 3.93 nm. The footprint of the device is 240 μm². The advantageous features of the proposed structure are valuable for integration based on popular planar technology and optical communications systems.

本文提出了一种使用二维光子晶体六角腔的紧凑型全光五通道解复用器（DEMUX）。提出的DEMUX包括总线/分支波导，包含四个连续的120°弯曲的光子晶体波导，两个功率分配器和六边形谐振腔。通过调整内部/耦合杆的半径和折射率，散射杆的位置和半径，可以管理每个端口的工作波长和输出功率。归一化的透射光谱和能带结构的计算分别通过有限差分时域（FDTD）和平面波扩展（PWE）方法进行。所提出的结构的共振波长分别为1328.7nm，1331.9nm，1335.4nm，1340.5nm和1344.4nm。计算结果表明，平均品质因数，光传输效率，通道通带，最小和最大串扰分别接近6236、95.98％，0.22 nm，− 18.04 dB和− 50.2 dB。DEMUX的工作波长范围是1328 nm至1345 nm，通道之间的平均通道间距接近3.93 nm。该设备的占地面积为240μm²。所提出的结构的有利特征对于基于流行的平面技术和光通信系统的集成是有价值的。