Fig. 1. Schematic diagram of frequency spectrum measurement

Fig. 2. Schematic diagram of the performance test system for EYDFA under radiation

Fig. 3. The noise spectrum detected by the signal analyzer with light and dark

Fig. 4. Evolution curve of the output power and PSD of EYDFA with radiation dose

Fig. 5. The evolution of the output spectrum of EYDFA with radiation dose

Fig. 6. Change of noise PSD of EYDFA as a function of output power before and after the process of gamma radiation