Abstract Broadband infrared luminescence covering the optical telecommunication wavelength region of O, E and S bands was observed from bismuth-doped zinc aluminosilicate glasses and glass-ceramics. The spectroscopic properties of the glasses and glass-ceramics depend on the thermal-treatment history. With the appearance of gahnite (ZnAl 2 O 4 ) crystalline phase, the fluorescent peak moves to longer wavelength, but the fluorescent intensity decreases. The $1300 nm fluorescence with a FWHM larger than 250 nm and a lifetime longer than 600 ls possesses these optical materials with potential applications in laser devices and broadband amplifiers. The broad infrared luminescence from the bismuth-doped zinc aluminosilicate glasses and glass-ceramics might be from BiO or bismuth clusters rather than from Bi 5+ and Bi 3+
