Fig. 1. Design of Tm-doped solid-core anti-resonant fiber. (a) Cross-section of the fiber; (b) CL of fundamental mode at different antiresonance orders; (c) Effect of refractive index difference between core and background region on loss of LP₀₁ and LP₁₁ mode and HOM suppression ratio at 2 μm

Fig. 2. (a) CL and (b) effective refractive index of LP₀₁ and high order modes at 2 μm for different cladding tube diameters

Fig. 3. CL of each mode of the designed Tm-doped tellurite anti-resonant fiber at 1.8-2.5 μm

Fig. 4. Laser output power and optical spectra of (a) 2.3 μm single wavelength amplification and (b) 1.9 μm, 2.3 μm dual wavelength amplification (The inset figure: laser optical spectrum)

Fig. 5. Amplified laser power of 2.3 μm band signal under different 1.9 μm signal input power

Fig. 6. Amplified laser power of the (a) 1.9 μm band signal, (b) 2.3 μm band signal, and (c) residual pump power under different specific wavelength and incident power of the 2.3 μm band seed

Fig. 7. Laser output power versus pump power and laser spectrum (the inset figure) at pump power of 100 W of the 1.9 μm and 2.3 μm dual wavelength amplifier