Ultra-compact dynamic OAM generator based on Sb2S3.

Integrated photonics is increasingly widely applied in fields such as optical communication and optical micro-operation, especially demonstrating great potential in the dynamic regulation of light wave characteristics. The orbital angular momentum (OAM) carried by vortex beams offers abundant orthogonal channels for optical communication; however, existing generation approaches frequently encounter issues such as large volume, high cost, and complex structure. This paper successfully realizes an ultra-compact dynamic OAM generation device by integrating phase-change materials with a trench waveguide. The device can dynamically generate OAM modes with topological charges of ±1, without changing the physical structure by taking advantage of the refractive index difference between the crystalline and amorphous states of the phase change materials. This design not only reduces the device length to 9.5µm but also enhances its applicability to multiple wavelengths of light waves, presenting extensive possibilities for the development of new photonic devices and systems in fields such as optical communication, quantum information processing, and optical micro-operation.