Assembling an endcap to optical fibers by femtosecond laser welding and milling

A novel method for assembling endcaps to optical fibers is presented. The method relies on femtosecond laser welding and milling of a glass slide to the polished end of the fiber. The fiber is welded to the glass slide in the cladding region so as to seal the core area without affecting its optical transparency. The same laser is used to mill through the glass slide thereby shaping a microscopic endcap with a diameter slightly larger than that of the fiber. The method was applied to both a standard and a microstructured optical fiber. Preliminary results are also presented on femtosecond laser welding parallel to an interface showing the potential of this approach for optical fiber fusion splicing.