45-degree curved micro-mirror for vertical optical I/O of silicon photonics chip.

The broadband vertical optical inputs/outputs (I/Os) of silicon (Si) photonics pose significant challenges in terms of practical applications. Herein, we worked on a vertical optical I/O using a 45° curved micro-mirror. To verify the optical coupling characteristics, a simulation was conducted. As a result, efficient broadband optical coupling with various types of single-mode optical fibers was obtained owing to its lens function. An integration technology of the curved mirror was also developed based on the semiconductor manufacturing process. A curved micro-mirror with a spherical surface was obtained, and the vertical optical I/O with its lens function was demonstrated experimentally.