400-nm-Bandwidth Emission From a Cr-Doped Glass Fiber

Cr⁴⁺-doped glass fiber by a laser-heated pedestal growth method is reported. By analyzing the absorption spectra, the transitions of Cr³⁺ and Cr⁴⁺ in the fibers are identified. With appropriate pumping wavelength and divalent doping concentration, both Cr³⁺ and Cr⁴⁺ emission bands can be excited simultaneously, and become comparable in their fluorescent intensities. As a result, more than 400-nm-width emission peaked at 1144 nm was generated at room temperature. As much as 12muW of amplified spontaneous emission was obtained by pumping with a 900-nm Ti : sapphire laser