Bismuth (Bi) -doped silicate glass for future photonics applications was proposed by Y. Fujimoto <i>et al</i>. in 2001 . And
its broadband fluorescence characteristic at 1.3um band was demonstrated for the first time. From this report, several
studies such as clarifying the fluorescence mechanism, surveying the optical properties of Bi-doped glass with various
host glass materials and so on have been done. However, there was no report on fabricating Bi-doped silicate glass fiber
(BiDF) for the demonstration of optical amplification and laser oscillation. In 2005, Haruna <i>et al</i>. succeeded in
fabricating the BiDF by Modified Chemical Vapor Deposition (MCVD) method for the first time, and evaluated its
absorption and fluorescent characteristics . In this report, the absorption bands around 0.5 um, 0.7 um, 0.8 um and
1.0um were shown, and the very wide fluorescence band with a FWHM of 192 nm centered at 1.06um was also
indicated. The background loss of the fiber was as low as <0.05 dB/m at 1.55 um because of the MCVD method that is
well-established method for the conventional optical fibers. Furthermore, the 1.3 um band amplification using the BiDF
prepared by the similar MCVD method was reported by V. V. Dvoyrin <i>et al</i>. in 2005 , and the laser oscillation by this
fiber was also demonstrated in 2006 . In this paper, a current research progress on the Bi-doped glasses and fibers is
reviewed. By looking at the optical properties such as fluorescence characteristics, future possible applications are
explained and its fluorescence mechanism is also discussed.
We have successfully demonstrated white-light continuum (WLC) generation in the near-infrared (NIR) region from 1.1 μm to 2.5 μm using specially designed highly nonlinear optical fibers. A passively mode-locked diode-pumped Er:Yb:glass laser with a semiconductor saturable-absorber mirror (SESAM) successfully generates femtosecond pulses with about 90 mW average output power, which is sufficient to produce the WLC with over 40 mW power without any additional optical amplification. This WLC source is expected to be suitable for many applications, such as laser radar systems and optical gas sensing.
Recent evolution of silica-based nonlinear fibers and their applications are reviewed. Important design issues of the fiber in order to enhance the nonlinearity and tailor the dispersion performance are discussed. In addition, recent demonstration results such as ultra-broadband wavelength conversion and supercontinuum generation experiments are also introduced in this paper.