Abstract

Since the discovery of a wideband (220-300 nm) infrared photoluminescence in bismuth containing alumosilicate glass centered in a 1.1-1.25 μm wavelength band, researchers have focused on exploiting this luminescence in oxide silicate glasses of various compositions for laser purposes [1]. Interest in this effect is mainly associated with the possibility to create Bi-doped fiber amplifiers in the second telecommunications window and for accomodating the future increase of data traffic in telecommunications optical fiber networks. The possibility of building femtosecond fiber lasers in a novel wavelength range is an added positive perspective. It is known that luminescence depends on the simultaneous presence of Bi with Al (or Ta) in the glass matrix, yet, the nature of the active optical center in Bi-doped glasses is still unclear [2]. The properties of host material and co-doping strongly affect the gain broadening and are instrumentalized for designing the optical amplifiers as well as tunable or mode-locked laser systems. Using other active atoms, earlier studies on fiber laser have shown that the character of the laser transition may vary across the gain bandwidth [3,4]. In particular, it has been shown that transient effects, such as relaxation oscillations, can depend on the operation wavelength. However, unlike the conventional active fiber laser materials such as Er, Yb, Tm and Nd, bismuth is not a rare earth element, and its dynamical behavior may therefore vary significantly.

© 2009 IEEE