Fabrication of 300-nm Cr-doped Fibers Using Fiber Drawing with Pressure Control

We demonstrate the fabrication of a broadband Cr-doped fiber using a drawing-tower method with a negative pressure control. In comparison with the fiber drawing without a negative pressure control, this new process significantly improve the quality and performance of the fabricated Cr-doped fibers. The Cr-doped fibers exhibited better core circularity, good continuity of drawing process, and excellent interface between core and cladding. The ASE spectrum showed a 300-nm broadband emission with the output power density of a few nW/nm. The results indicate that this new Cr-doped fiber may be used as a broadband fiber amplifier to cover the bandwidths in the whole 1.3-1.6 μm.