Novel pumping schemes for fluoride-based thulium-doped fiber amplifier at 690 and 1050 nm (or 1400 nm)

Signal amplification in the S- and S⁺-band is demonstrated for the first time by simultaneous pumping of thulium-doped fiber amplifier (TDFA) with 690 and 1050 nm (or 1400 nm). Both pumping schemes are investigated and shown to be highly efficient: Roughly 20 dB of signal gain is available with only 80 mW of 1050 nm plus 42 mW of 690 nm, while signal input power is fixed at -35 dBm. Furthermore, these excitations can take advantage of low-cost readily available pump laser diodes at 690 nm for digital video disk applications. This makes TDFA a promising candidate for coarse wavelength-division-multiplexing applications in metropolitan area network and access network environment.