Fig. 1. Writing method and spectrum of FBG. (a) Schematic diagram of inscribing FBG based on femtosecond laser phase mask scanning method; (b) reflectance spectra of HR-FBG and OC-FBG

Fig. 2. Structural diagram of integrated all-fiber oscillator

Fig. 3. Temperature of HR-FBG and OC-FBG varying with optical power of forward output signal when pumping inside or outside cavity, respectively. (a) HR-FBG; (b) OC-FBG

Fig. 4. Forward output power and backward output power varying with pump power when pumping inside or outside cavity, respectively. (a) Forward output power; (b) backward output power

Fig. 5. Forward and backward output spectra at different output powers under two-point distributed pumping. (a) Forward output spectrum; (b) backward output spectrum

Fig. 6. Output power and optical-optical conversion efficiency varying with pump power under two-point distributed pumping.(a) Output power; (b) optical-optical conversion efficiency

Fig. 7. Temperature characteristics of FBGs and couplers and M² factor varying with forward output power under two-point distributed pumping. (a) Temperature characteristics of FBGs and couplers; (b) M² factor varying with forward output power