Fiber used in wideband amplified spontaneous emission light source and the method of making the same

A wideband amplified spontaneous emission light source comprising:

• a pumping light source for generating a pumping light;
• a fiber having a core doped with chromium ions, a borosilicate glass cladding enclosing the core, and an inter-diffusion layer between the core and the borosilicate glass cladding, the core being Cr4+:YAG and doped with Cr2O3, the core further doped with CaO or MgO, the core being a cylinder and the borosilicate glass cladding enclosing all sides but not ends of the core, the inter-diffusion layer being a mixture of the material of the core and the material of the borosilicate glass cladding, the inter-diffusion layer having Cr3+:γ-Al2O3 nanocrystals, the core being a single crystal, the fiber being connected to the pumping light source for receiving the pumping light so as to excite the chromium ions therein;
• and
• an output port connected to the fiber and used for outputting amplified spontaneous emission (ASE) light.