1535–1620 nm Widely Tunable Watt-Level Single-Mode Er:Yb Codoped All-Fiber MOPA

We report a continuous-wave 1535-1620 nm widely tunable single-mode Er:Yb codoped cladding-pumped all-fiber laser source based on the MOPA scheme. The output power ranged from 0.785 W (at 1615 nm) to 2.007 W (at 1565 nm), which is the highest output power from a C+L tunable all-fiber laser source. The 3 dB spectral width was less than 150 pm at all wavelengths. No Yb emission was observed. We proposed a mid-way backward pumping configuration in which the pump light was injected between two gain fibers and propagated backward to broaden the effective wavelength range of the fiber amplifier. Experiments verified the capability of our configuration to improve the suppression ratio of C-band amplified spontaneous emissions from 13 dB to 35 dB when the signal laser was operating at 1620 nm.