Quantumefficiency ofabroadband near-infrared emission fromNi2-doped Li20-Ga203-SiO2 transparent glass-ceramics

.acjp Broadband amplifiers and tunable lasers are keydevices forthedevelopment of dense wavelength-division-multiplexing (DWDM)network systems.Manyefforts havebeenmadetorealize ultra-broadband optical amplification forDWDM useusing rare-earth-doped fiber andfiber Ramanamplifiers. Though transition metal ions haveapotential asactive ions forultra-broadband optical amplification, non-radiative decay processes dominate therelaxations oftheexcited states oftransition metals andthequantum efficiency of transition metals isverylowinglasses. They canhavesufficiently large quantum efficiency insingle crystals. However, itisdifficult toobtain single crystal fibers. Incontrast, glasses canbeeasily obtained aslarge size bulk andthey canbeused asfiber andwaveguide materials. Glass-ceramics areofinterest ashosts fortransition metals, since they havetheadvantage ofbothmechanical properties like glass materials andoptical properties like single crystalline materials. Ifthesizes ofcrystals inglass-ceramics arefarless thanthewavelength ofinterest, light scattering caused bythecrystals would benegligible andsuchglass-ceramics arecalled transparent glass-ceramics.