Wang Chaofeng, Liu Houwen, Long Xue, Zhou Ya, Wu Jia, He Li, Mao Lili, Li Hongbo, Nie Kuiying, Hu Zonghua, Guan Zhiwei, Chen Shuqing
Opt Express. 2025 Jun 30;33(13):28711-28725. doi: 10.1364/OE.565113.
Mode multiplexing, which transmits parallel data information via orthogonal light field modes, has attracted extensive research attention in on-chip high-capacity optical communication. To reduce the device footprint, a mode multiplexer with sub-wavelength pixelated superstructures is proposed. However, due to the accumulation of device fabrication deviation, the communication performance of mode multiplexer will be deteriorated. Herein, we propose a pixelated superstructure duty cycle optimization strategy to decrease the number of cylindrical air holes, which can mitigate the cumulative disturbance of fabrication deviation. The duty cycle of pixelated superstructure is adjusted by eliminating pixels below the specified Figure of Merit threshold, achieving an improvement from 20.6% to 13.9%. Based on this, we optimize a three-mode multiplexer (TE0, TE1, TE2) and demonstrate a mode multiplexing communication by transmitting 72 QPSK-OFDM signals. The experimental results show that the insertion loss of the fabricated three-mode multiplexer reduces by approximately 1.9 ∼ 2.8 compared with the direct binary search scheme, and the communication sensitivity is optimized about 1.5 at the center wavelength of 1550 . Our proposed pixelated superstructure duty cycle optimization strategy performs the pixel updating or random mutation by means of roulette method, increasing the randomness of value search during algorithm execution, which will prevent the target value from falling into a local optimal solution. This work is expected to promote the development of on-chip mode multiplexing and provide what we believe to be new technological paths for high-capacity optical communications.
模式复用通过正交光场模式传输并行数据信息，在片上高容量光通信中引起了广泛的研究关注。为了减小器件尺寸，提出了一种具有亚波长像素化超结构的模式复用器。然而，由于器件制造偏差的累积，模式复用器的通信性能会变差。在此，我们提出一种像素化超结构占空比优化策略，以减少圆柱形气孔的数量，从而减轻制造偏差的累积干扰。通过消除低于指定品质因数阈值的像素来调整像素化超结构的占空比，实现了从20.6%到13.9%的提升。基于此，我们优化了一个三模式复用器（TE0、TE1、TE2），并通过传输72个QPSK-OFDM信号演示了模式复用通信。实验结果表明，与直接二分搜索方案相比，所制备的三模式复用器的插入损耗降低了约1.9 ∼ 2.8，并且在1550的中心波长处通信灵敏度优化了约1.5。我们提出的像素化超结构占空比优化策略通过轮盘赌方法进行像素更新或随机变异，增加了算法执行过程中值搜索的随机性，这将防止目标值陷入局部最优解。这项工作有望推动片上模式复用的发展，并为高容量光通信提供我们认为的新技术路径。
