An apparatus and method for thermally tuning an optical amplifier comprises
an optical waveguide doped with a fluorescent material, a thermal device
for either heating or cooling the optical waveguide, and a pump light for
exciting the fluorescent material. The apparatus shapes, shifts, and/or
flattens the gain curves of the doped optical amplifier. Thulium doped
fiber is cooled to shift the gain curve into the C-band. Erbium doped
fiber is heated to flatten the gain curve in the C-band and is cooled to
shift the gain curve above the L-band. The apparatus similarly shapes the
gain curves of other fluorescent materials. The thermal device comprises
three types of optical cooling devices. The apparatus is a component in
communications systems, lasers, medical lasers and the like. The method
comprises either heating or cooling optical waveguides doped with
fluorescent materials to achieve the desired shaping, shifting, and
flattening of the gain curves.
