Zhang Ruhuan, Deng Chuanlu, Huang Yi, Zhang Fang, Zhang Xiaobei, Wang Tingyun
Opt Express. 2022 Aug 1;30(16):28492-28505. doi: 10.1364/OE.462881.
In this paper, we present an efficient polymer two-mode (de)multiplexer with two cascaded horizontal waveguide asymmetric directional couplers (ADCs). Through extensive simulations, the optimized waveguide core dimensions were determined, and the distance L from the starting position of the first ADC to the cascaded position was 35300 µm. With the cascaded ADCs, the 21 mode of the wider waveguide was coupled into the 11 mode of the narrower waveguide with a coupling ratio of 96.73% at 1550 nm when the separation between the waveguide cores was 5 µm. The coupling ratio and extinction ratio of the fabricated (de)multiplexer reached a maximum of 96.12% and 14.21 dB at 1540 nm, respectively. The coupling ratios were greater than 90% in the wavelength range 1533-1565 nm with a minimum insertion loss of 9.75 dB. The influence of different cascaded positions on the mode coupling ratio, mainly caused by the large phase difference between the modes owing to the slowly varying envelope approximation, is analyzed theoretically and verified experimentally. The proposed cascaded two-mode (de)multiplexer can reduce the preparation process requirements and increase the channel capacity of optical communication systems.
在本文中，我们展示了一种高效的聚合物双模式复用/解复用器，它由两个级联的水平波导非对称定向耦合器（ADC）组成。通过大量的模拟，确定了优化的波导芯尺寸，从第一个ADC的起始位置到级联位置的距离L为35300 µm。利用级联的ADC，当波导芯之间的间距为5 µm时，在1550 nm处，较宽波导的21模式以96.73%的耦合比耦合到较窄波导的11模式。所制备的复用/解复用器的耦合比和消光比在1540 nm处分别达到最大值96.12%和14.21 dB。在1533 - 1565 nm波长范围内，耦合比大于90%，最小插入损耗为9.75 dB。理论分析并实验验证了不同级联位置对模式耦合比的影响，这主要是由于缓慢变化包络近似导致模式之间存在较大相位差。所提出的级联双模式复用/解复用器可以降低制备工艺要求并增加光通信系统的信道容量。
