No abstract

We report on ultracompact cladding-pumped fiber lasers, fabricated from single-mode phosphate glass microstructured optical fibers, with several watts of cw output at 1.5μm. A maximum cw output power of 4.7W has been achieved from a fiber laser that is only 35mm in length, corresponding to a yield of 1.34W∕cm of active microstructured fiber.

We present what is, to the best of our knowledge, the first systematic study on how negative core-cladding index difference influences microstructured optical fiber's modal behavior. Single-mode lasing has been realized for short-length cladding-pumped phosphate glass microstructured fibers with large depressed-index Er(3+)-Yb(3+)-codoped cores.