Mitigation of optical losses is of prime importance for the performance of integrated micro-photonic devices. In this paper, we demonstrate strip-loaded guiding optical components realized on a 27 nm ultra-thin silicon-on-insulator (SOI) platform. The absence of physically etched boundaries within the guiding core majorly suppresses the scattering loss, as shown by us previously for a silicon nitride (${\mathrm{Si}}_3{\mathrm{N}}_4$) platform. Unexpectedly, the freshly fabricated Si devices showed large losses of 5.1 dB/cm originating from absorption by free carriers, accumulated under the positively charged ${\mathrm{Si}}_3{\mathrm{N}}_4$ loading layer. We show how ultraviolet (UV, 254 nm) light exposure can progressively and permanently neutralize ${\mathrm{Si}}_3{\mathrm{N}}_4$’s bulk charge, associated with diamagnetic $K^{+}$ defects. Consequently, the net decrease of electron concentration in the SOI layer reduces the propagation loss down to 0.9 dB/cm. Accurate cavity linewidth measurements demonstrate how the intrinsic cavity’s $Q$ boosts from 70,000 up to 500,000 after UV illumination. Our results may open routes towards engineering of new functionalities in photonic devices employing UV modification of space-charge-associated local electric fields, unveil the origin of induced optical nonlinearities in ${\mathrm{Si}}_3{\mathrm{N}}_4/\mathrm{Si}$ micro-photonic systems, as well as envisage possible integration of these with both standard and ultra-thin SOI electronics.

中文翻译：

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永久减轻超薄绝缘体上硅的高损耗$\mathsf{问}$ 使用紫外线的谐振器

减少光损耗对于集成微光子设备的性能至关重要。在本文中，我们演示了在27 nm超薄绝缘体上硅（SOI）平台上实现的带载引导光学组件。如我们先前对氮化硅（${硅}_3{\mathrm{ñ}}_4$） 平台。出乎意料的是，新制作的Si器件显示出5.1 dB / cm的大损耗，这是由于自由载流子在正电荷下的吸收所导致${硅}_3{\mathrm{ñ}}_4$加载层。我们展示了紫外线（UV，254 nm）曝光如何逐渐和永久中和${硅}_3{\mathrm{ñ}}_4$的大电荷，与抗磁性有关 ${ķ}^{+}$缺陷。因此，SOI层中电子浓度的净降低将传播损耗降低至0.9 dB / cm。准确的腔线宽测量表明了固有腔的$问$紫外线照射后从70,000升至500,000。我们的结果可能为在空间电荷相关局部电场中进行UV修饰的光子器件中新功能的工程化开辟道路，揭示了感应光非线性的起源。${硅}_3{\mathrm{ñ}}_4/硅$ 微光子系统，并设想将它们与标准和超薄SOI电子设备集成在一起。