The heterogeneous integration of photonic integrated circuits (PICs) with a diverse range of optoelectronic materials has emerged as a transformative approach, propelling photonic chips toward larger scales, superior performance, and advanced integration levels. Notably, two-dimensional (2D) materials, such as graphene, transition metal dichalcogenides (TMDCs), black phosphorus (BP), and hexagonal boron nitride (hBN), exhibit remarkable device performance and integration capabilities, offering promising potential for large-scale implementation in PICs. In this paper, we first present a comprehensive review of recent progress, systematically categorizing the integration of photonic circuits with 2D materials based on their types while also emphasizing their unique advantages. Then, we discuss the integration approaches of 2D materials with PICs. We also summarize the technical challenges in the heterogeneous integration of 2D materials in photonics and envision their immense potential for future applications in PICs.

为了提高偏振分束器的消光比，提出了一种由混合等离子体水平狭缝波导(HSW)和氮化硅混合垂直狭缝波导(VSW)组成的双槽超紧凑偏振分束器(PBS)。同时，包层材料为二氧化硅，既能防止混合等离子体氧化，又便于与其他器件集成。采用有限元方法仿真HSW和VSW的模态特性。HSW和VSW波导在特定的宽度下TE偏振模式是满足相位匹配的，而TM偏振模式相位不匹配。因此，HSW波导中的TE模式与VSW波导发生强耦合，而TM模式直接通过HSW波导。结果表明：在1.55 μm的TE模式下，PBS的消光比(ER)为35.1 dB，插入损耗(IL)为0.34 dB，在TM模式下，PBS的ER和IL分别为40.9 dB和2.65 dB。所设计的PBS有100 nm的工作带宽，具有高ER，低IL的特点，适用于光子集成电路(PICs)。

光子集成芯片将多种功能器件进行片上集成，具有损耗低、带宽大、抗电磁干扰等优势，是当前光电领域发展的主流方向。集成光学器件的温度稳定性是影响其光学性能的重要因素之一。为了提高集成光学器件温度稳定性，提出了基于氮化硅（Si₃N₄）和长程表面等离激元（Long-Range Surface Plasmon Polariton，LRSPP）波导的温度不敏感结构，对器件性能随温度的漂移进行抑制和补偿。首先，分析了Si₃N₄波导和LRSPP波导对接的模式耦合效率，当满足最佳匹配条件时，可实现耦合效率99.9%以上的高效耦合。对混合波导的温度特性进行了分析，结果表明，当LRSPP波导和Si₃N₄波导的最佳长度比为 0.077，相位不随温度的变化而发生漂移，实现了温度不敏感的波导。当波导不能满足最佳长度比时，对LRSPP波导芯层施加电压实现主动补偿，亦可实现温度不敏感。此外，对LRSPP波导的传输特性进行了测试，测得偏振消光比为64 dB，具有良好的单偏振特性。文中提出的温度不敏感结构具有可主动调谐、损耗低、单偏振、普适性高等优点，能有效地解决Si₃N₄波导性能随温度变化发生漂移的问题，在Si₃N₄基光子集成芯片中具有广泛的应用前景。

Photonics on thin-film lithium niobate (TFLN) has emerged as one of the most pursued disciplines within integrated optics. Ultracompact and low-loss optical waveguides and related devices on this modern material platform have rejuvenated the traditional and commercial applications of lithium niobate for optical modulators based on the electro-optic effect, as well as optical wavelength converters based on second-order nonlinear effects, e.g., second-harmonic, sum-, and difference-frequency generations. TFLN has also created vast opportunities for applications and integrated solutions for optical parametric amplification and oscillation, cascaded nonlinear effects, such as low-harmonic generation; third-order nonlinear effects, such as supercontinuum generation; optical frequency comb generation and stabilization; and nonclassical nonlinear effects, such as spontaneous parametric downconversion for quantum optics. Recent progress in nonlinear integrated photonics on TFLN for all these applications, their current trends, and future opportunities and challenges are reviewed.

由于金属固有的欧姆损耗，表面等离子体波导通常具有较大的传输损耗。基于此，提出了一种全介质反槽波导结构，该波导可以同时实现亚波长模式局域性和理论上无损耗的传输，归一化模式面积可以达到3.4×10^-2。另外，为了实现该小尺寸反槽波导与输入/输出光纤的高效耦合，提出了一种高效的耦合方案，耦合效率可以达到92.7%，在y和z方向上1 dB损耗的耦合偏差均约为2 μm。