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A tunable and low-threshold thulium (Tm)-doped fiber (TDF) laser is demon- strated using a new silica-based nanoengineered TDF in a linear configuration, in con- junction with 1552-nm pumping. The TDF used in these experiments had a Tm-doped nanoengineering yttrium-alumina-silica glass core with a diameter of 13.43 � m and 0. 21 NA, which is surrounded by a pure silica inner cladding with normal acrylate polymer resin coating. The nanoengineered TDF was fabricated using a modified chemical vapor deposition (MCVD) process, in conjunction with a solution-doping technique. The fabricated fiber shows an absorption loss of 165 dB/m at 793 nm. A maximum lasing slope efficiency of 26.2% was obtained at a 1910-nm wavelength using the fabricated fiber with an optimum length of 5 m. The maximum output power of 138 mW was achieved at the maximum pump power of 1100 mW. The lowest pump power threshold of 693 mW for a 1552-nm wave- length was obtained at a TDF length of 7 m. The operating wavelength of the laser could be continuously tuned from 1890 to 1910 nm with an optical signal-to-noise ratio better than 43 dB, whereas the slope efficiency of the laser varies from 16.4% to 19.7%.

A wide-band and flat gain Erbium-doped fiber amplifier (EDFA) is demonstrated using a gain media of high concentration Silica-based erbium doped fiber (EDF). The amplifier has two stages comprising a 1.5 m and 9 m long EDF optimized for C-band and L-band operations respectively, in a double-pass series configuration. The CFBG is used in both stages to allow a double propagation of signal and thus increases the attainable gain in both C- and L-band spectra. At an input signal power of −30 dBm, a flat gain of 22 dB is achieved with a gain variation of ±3 dB within a wide wavelength range from 1530 to 1600nm. The corresponding noise figure varies from 4 to 8 dB within this wavelength region.

A flat gain Erbium-doped fiber amplifier (EDFA) is demonstrated using a gain media of high concentration Silica-based erbium doped fiber (EDF). The amplifier has one stage comprising a 1.5 m and 9 m long EDF optimized for C-band and L-band operations respectively, in a single-pass and double-pass configuration. The CFBG is used at the end of EDF to allow a double propagation of signal and thus increases the attainable gain in both C- and L-band spectra. At input signal power of -30 dB, the averaged flat gain of approximately 25 dB over C-band region and the averaged flat gain of approximately 30 dB over L-band region are achieved by the double-pass amplifier with gain variation approximately ±3 dB. The corresponding noise figure is maintained at 5 dB with noise figure variation ±0.5 dB.