Dispersion engineering of tellurite holey fiber with holes formed by two glasses for highly nonlinear applications

Tellurite nonlinear holey fiber is characterized by a high nonlinearity and a broad transparent window. However, these advantages are canceled by its unflattened dispersion in most practical applications. The unflattened dispersion is due to the fact that tellurite holey fiber with complex structure is difficult to fabricate. In this work we develop a dispersion flattened tellurite composite holey fiber (TCHF). The TCHF has only one ring of holes. The holes are formed by two tellurite glasses. The heavy deformation, which probably occurs for tellurite complex microstructured fiber during the fabrication process, is avoided by this simple structure. The fiber is made of two glasses with different refractive-indices, which improves the flexibility in dispersion engineering. By using this structure the dispersion is engineered to be the most flattened for the highly nonlinear soft glass fiber within 1.5–1.6 μm. Owing to the flattened dispersion and high nonlinearity, more than one octave supercontinuum generation is demonstrated by a femtosecond fiber laser.