S-band Thulium-doped fiber amplifier enhancement using ASE suppression

A new method for gain enhancement in S-band Thulium-doped fiber amplifier (TDFA) co-doped with Aluminum is demonstrated using a photonic crystal fiber and macro-bending approach. The photonic crystal fiber and macro-bending methods suppresses both amplified spontaneous emissions (ASEs) at 800 nm and 1800 nm band and thus increases the population inversion in S-band region. Gain enhancements of about 5~8 dB are obtained at the wavelength region between 1420 and 1470 nm.