Sai Xiaowei, Li Yan, Yang Chen, Li Wei, Qiu Jifang, Hong Xiaobin, Zuo Yong, Guo Hongxiang, Tong Weijun, Wu Jian
Opt Lett. 2017 Nov 1;42(21):4355-4358. doi: 10.1364/OL.42.004355.
Elliptical-core few mode fiber (EC-FMF) is used in a mode division multiplexing (MDM) transmission system to release multiple-input-multiple-output (MIMO) digital-signal-processing, which reduces the cost and the complexity of the receiver. However, EC-FMF does not match with conventional multiplexers/de-multiplexers (MUXs/DeMUXs) such as a photonic lantern, leading to extra mode coupling loss and crosstalk. We design elliptical-core mode-selective photonic lanterns (EC-MSPLs) with six modes, which can match well with EC-FMF in MIMO-free MDM systems. Simulation of the EC-MSPL using the beam propagation method was demonstrated employing a combination of either step-index or graded-index fibers with six different sizes of cores, and the taper transition length of 8 cm or 4 cm. Through numerical simulations and optimizations, both types of photonic lanterns can realize low loss transmission and low crosstalk of below -20.0 dB for all modes.
椭圆芯少模光纤（EC - FMF）用于模分复用（MDM）传输系统，以实现多输入多输出（MIMO）数字信号处理，从而降低接收器的成本和复杂度。然而，EC - FMF与诸如光子灯笼等传统复用器/解复用器（MUXs/DeMUXs）不匹配，会导致额外的模式耦合损耗和串扰。我们设计了具有六种模式的椭圆芯模式选择光子灯笼（EC - MSPLs），其在无MIMO的MDM系统中能与EC - FMF良好匹配。利用光束传播法对EC - MSPL进行了仿真，采用了具有六种不同纤芯尺寸的阶跃折射率光纤或渐变折射率光纤的组合，以及8厘米或4厘米的锥形过渡长度。通过数值模拟和优化，两种类型的光子灯笼都能实现所有模式下低于 - 20.0 dB的低损耗传输和低串扰。
