  A narrow linewidth laser operating at the telecommunications band combined
with both fast and wide-band tuning features will have promising applications.
Here, we demonstrate a single-mode (both transverse and longitude mode)
continuous microlaser around 1535 nm based on a fiber Fabry-P\'erot
microcavity, which achieves wide-band tuning without mode hopping to 1.3 THz
range and fast tuning rate to 60 kHz, yields a frequency scan rate of
$1.6\times10^{17}$ Hz/s. Moreover, the linewidth of the laser is measured as
narrow as 3.1 MHz. As the microlaser combines all these features into one fiber
component, it can serve as the seed laser for versatile applications in optical
communication, sensing, frequency-modulated continuous-wave radar and high
resolution imaging.
