光子晶体双波长电光调制和模分复用集成器件

为了实现光电子器件小型化和多功能化，进一步提高信息传输容量和速度，提出了一种基于光子晶体双波长电光调制和模分复用的片上集成器件。该集成器件的电光调制模块由硅基光子晶体波导和两个L3型复合腔组成，模分复用模块由硅基非对称平行纳米线波导组成，两个模块的连接处采用硅基光子晶体波导。采用L3型复合腔和PN掺杂结构实现两个波长TE₀模的调制，采用非对称定向耦合结构将两个波长的TE₀模转换为TE₁模。应用基于三维时域有限差分法（3D-Finite Difference Time Domain，3D-FDTD）的Lumerical软件进行仿真分析，结果表明，在调制电压为1.05 V时，该集成器件可以实现中心波长为1 552.1 nm和1 556.1 nm的 TE₀模、TE₁模通断调制及两模式模分复用功能。该器件的消光比高达24.67 dB，调制深度均为0.99，插入损耗小于0.57 dB，信道串扰小于?34.68 dB，调制速率最低为17.54 GHz。该集成器件结构紧凑，可望应用于高速大容量光通信系统。

Integrated device of dual-wavelength electro-optic modulating and mode-division multiplexing based on photonic crystal

In order to realize the miniaturization and multi-function of optoelectronic devices and further improve the capacity and speed of information transmission, an on-chip integrated device based on photonic crystal for dual-wavelength electro-optic modulation and mode division multiplexing (MDM) is proposed. The electro-optical modulation module of the integrated device is composed of a silicon-based photonic crystal waveguide and two L3 composite resonators, and the MDM module consists of silicon-based asymmetric parallel nanowire waveguides. A silicon-based photonic crystal waveguide is used at the junction of the two modules. The L3 composite resonators and PN doping structure are used to achieve the modulation of the two-wavelength TE₀ mode, and the asymmetric directional coupling structure is used to convert the TE₀ mode of two wavelengths into the TE₁ mode. The parameters of the integrated device are calculated using three-dimensional finite-difference time-domain (3D-FDTD) method. The results show that when the voltage is 1.05 V, the integrated device can achieve a center wavelength of 1 552.1 nm and 1 556.1 nm TE₀ mode, TE₁ mode on-off modulation and two-mode mode division multiplexing function. The extinction ratio of the device is as high as 24.67 dB, and the modulation depths are both 0.99. The insertion loss and the channel crosstalk are less than 0.57 dB and ?34.68 dB, respectively. And the minimum modulation speed is 17.54 GHz. The integrated device has compact structure and is expected to be applied to high-speed and large-capacity optical communication systems.