The state-of-the-art optical coherence technology (OCT) has its limitation, such as bulky and quite expensive. Miniaturization and integration of the OCT system are promising to get a compact, less costly, and more stable device. In this paper, we report the influence of optical power splitting on the sensitivity and axial resolution in spectral-domain OCT (SD-OCT) on silicon chip using tandem Mach-Zehnder directional coupler (MZDC) based broadband coupler through particle swarm optimization (PSO). A less-flat wavelength response from a broadband coupler in an interferometer for SD-OCT on-chip will decrease the sensing sensitivity. The arrayed waveguide grating (AWG) as a spectrometer in SD-OCT typically suffers from the axial resolution degradation due to the non-flat free spectrum range (FSR). To avoid the higher optical loss from the large FSR, the PSO manipulation in MZDC is then proposed to demonstrate U-shaped wavelength compensation on the non-flat AWG spectrum. With the broadband coupler configuration, a SD-OCT on-chip can maintain the sensitivity and axial resolution performance.

中文翻译：

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基于阵列波导光栅的光学相干断层扫描通过粒子群优化宽带耦合器操作

最先进的光学相干技术 (OCT) 有其局限性，例如体积庞大且价格昂贵。OCT 系统的小型化和集成化有望获得紧凑、成本更低且更稳定的设备。在本文中，我们通过粒子群优化 (PSO) 报告了使用基于串联 Mach-Zehnder 定向耦合器 (MZDC) 的宽带耦合器在硅芯片上的光谱域 OCT (SD-OCT) 中光功率分配对灵敏度和轴向分辨率的影响）。片上 SD-OCT 干涉仪中宽带耦合器的不平坦波长响应会降低传感灵敏度。由于非平坦自由光谱范围 (FSR)，阵列波导光栅 (AWG) 作为 SD-OCT 中的光谱仪通常会遭受轴向分辨率的降低。为了避免大 FSR 带来的更高光损耗，然后建议在 MZDC 中进行 PSO 操作以演示非平坦 AWG 光谱上的 U 形波长补偿。通过宽带耦合器配置，片上 SD-OCT 可以保持灵敏度和轴向分辨率性能。