Van der Waals photonic integrated circuit with coherent light generation.

Two-dimensional semiconductors hold great potential as coherent light sources for photonic integrated circuits. However, the conventional integration of two-dimensional materials onto silicon photonics introduces significant structural and optoelectronic drawbacks, hindering the practical realization of coherent photonic circuits. Here, we introduce the concept of a van der Waals photonic integrated circuit, which is a complete on-chip optical system fabricated entirely from a van der Waals heterostructure. By combining multifunctional two-dimensional materials into a single heterostructure, we realize a fully functional photonic circuitry capable of benchtop coherent light generation, propagation, transmission, and modulation via a silicon back gate. The monolithic approach to heterostructure circuitry supports the effective integration of various photonic components based on two-dimensional materials with stable electro-optic interconnections. The coherence of light emission is systematically verified by second-order correlation experiments at room temperature, showing a clear power-dependent transition to a Poissonian regime. Our work establishes a pathway for coherent van der Waals photonics incorporated with standard silicon manufacturing processes.