Two-dimensional materials in photonic integrated circuits: recent developments and future perspectives [Invited]

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.