In-phase supermode selection in ring-type and concentric-type multicore fibers using large-mode-area single-mode fiber.

We propose an all-fiber-optic supermode selection scheme based on large-mode-area single-mode fiber for multicore fiber (MCF). The supermode selection in terms of the coupling coefficient is investigated and compared for various ring-type and concentric-type MCFs. The in-phase supermode is found to have a significantly higher coupling coefficient than other supermodes--demonstrating significant and desirable supermode selection characteristics. This scheme has shown better in-phase supermode selection performance than the conventional free-space Talbot cavity. It is found to be effective in selecting the in-phase supermode for both ring-type and concentric-type MCFs and promising for all-fiber MCF lasers with high power output and good beam quality.