Dielectric metasurface for single-mode fiber edge coupling

Achieving efficient optical power transfer between photonic components has been a critical challenge across various areas in photonics and optoelectronics. Particularly, establishing effective optical coupling between high numerical aperture (NA) photonic integrated circuit (PIC) and conventional single-mode fiber (SMF) remains a crucial requirement for ensuring reliable optical signal transmission in modern photonic systems. This paper presents an innovative metasurface-based fiber coupling solution, leveraging two-dimensional subwavelength nanostructure to achieve precise mode field matching between high-NA and standard SMFs. By utilizing the excellent capability of metasurface in amplitude, phase and polarization modulation, numerical simulations show a record coupling efficiency of 99.1% at the wavelength of 1550nm. Significantly, the metasurface-based SMF coupler achieves micrometer scale longitudinal packaging dimensions in contrast to conventional edge coupling schemes, offering a transformative solution for implementing integrated photonic packaging. Further simulation analysis of the impact of lateral and longitudinal alignment offsets on coupling efficiency provides important design basis for tolerance control in actual packaging processes.