Fig. 1. LD output characteristics vary with temperature^[66]. (a) Output spectra; (b) output power and central wavelength

Fig. 2. Test results of temperature characteristics of HR-FBG and OC-FBG^[66]. (a) HR-FBG reflection spectra; (b) HR-FBG 3 dB bandwidth and central wavelength; (c) OC-FBG reflection spectra; (d) OC-FBG 3 dB bandwidth and central wavelength

Fig. 3. Absorption and emission cross sections of YDF at different temperatures^[69]. (a) Absorption cross section; (b) emission cross section

Fig. 4. Variation of beam quality with output power^[79]

Fig. 5. Variation of TMI threshold and optical-to-optical efficiency of oscillator with cooling temperature of YDF^[83]

Fig. 6. Raman spectra of silicon samples at 20 K, 460 K, and 770 K^[84]

Fig. 7. Amplifier output spectra at different temperatures^[14]. (a) 20 ℃; (b) 8 ℃

Fig. 8. 2 kW wide temperature operation fiber oscillator^[66]. (a) Schematic of the oscillator structure; (b) variation curves of laser output power with output time

Fig. 9. kW-level wide temperature operation fiber oscillator^[93]. (a) Schematic of the oscillator structure; (b) output power and efficiency of laser at different temperatures