Femtosecond lasers based on dispersion compensation with hybrid fiber

The key point in fabrication of all-fiber ultra-fast lasers operating near 1 μm is utilization of fibers with anomalous dispersion. A number of works were devoted to design of specialty fibers for this aim (Photonic Crystal fibers, Photonic Bandgap fibers, hollow core fibers, high order mode fiber and etc). However none of these fiber types have found wide commercial use due to its inherent disadvantages (high nonlinearity, high loss, few-modes operation regime and etc). Recently we have developed a novel promising fiber design, so called hybrid fiber [1]. Operating hybrid mode has anomalous dispersion of 10–100 ps/(nm-km), and could be excited by simple splicing with a standard step-index fiber. Asymptotically singlemode operation regime of hybrid fiber can be obtained by introduction in the structure of absorbing layer that suppresses all unwanted modes [2].