Saha Prapty, Aminul Oruni, Rahman Md Atiqur, Alam Md Shah, Ahmmed Kazi Tanvir
Department of Electrical and Electronic Engineering, University of Chittagong, Chittagong, 4331, Bangladesh.
Heliyon. 2022 Nov 18;8(11):e11706. doi: 10.1016/j.heliyon.2022.e11706. eCollection 2022 Nov.
In mode division multiplexing (MDM) optical system, the mode filter has become an inseparable part to reduce modal crosstalk and transmit the desired modes unabatedly. As filtering out lower-order mode is difficult, here we propose a reconfigurable structure of a higher-order mode pass filter consisting of two tunable mode converters and a directional coupler (DC) in a three-mode planar waveguide platform. By switching the working states of the mode converters, the structure can also be used as a fundamental mode (TE) pass filter and hence dynamic output signals can be achieved. For the second-order mode (TE) transmission, the simulated excess loss is ∼0.61 dB at 1.550 μm and the extinction ratio remains ≥24 dB (power ratio of TE & TE Launch) and ≥25 dB (power ratio of TE & TE Launch) at the entire C-band (1.530-1.565 μm). The device has negligible polarization dependence and hence the TM polarization exhibits similar results.
在模式分割复用（MDM）光学系统中，模式滤波器已成为减少模式串扰并毫无衰减地传输所需模式的不可或缺的一部分。由于滤除低阶模式很困难，在此我们提出一种高阶模式通滤波器的可重构结构，该结构由三模平面波导平台中的两个可调谐模式转换器和一个定向耦合器（DC）组成。通过切换模式转换器的工作状态，该结构还可以用作基模（TE）通滤波器，从而可以实现动态输出信号。对于二阶模式（TE）传输，在1.550μm处模拟的额外损耗约为0.61dB，并且在整个C波段（1.530 - 1.565μm）消光比保持≥24dB（TE与TE发射的功率比）和≥25dB（TE与TE发射的功率比）。该器件的偏振依赖性可忽略不计，因此TM偏振也表现出类似的结果。
