Fig. 1. Structural diagram of iodine frequency-stabilized laser

Fig. 2. Sine wave generator

Fig. 3. 1 kHz sine wave. (a) Waveform plot; (b) spectrogram

Fig. 4. Block diagram of demodulator principle

Fig. 5. Harmonic signals. (a) 2nd harmonic; (b) 3rd harmonic

Fig. 6. 3rd harmonic signals for peaks d, e, f, and g

Fig. 7. Analog-digital hybrid PID controller. (a) Structure diagram; (b) effect of frequency stability

Fig. 8. Identification effect of absorption peaks. (a) Identification of peak d; (b) identification results of 14 absorption peaks

Fig. 9. Overall algorithm flowchart

Fig. 10. Beat frequency monitoring result

Fig. 11. Optical comb beat frequency result

Fig. 12. Frequency stability of iodine-stabilized laser