Fig. 1. Schematic of horizontal modulation OVS

Fig. 2. Internal structure section of OVS sensing head

Fig. 3. BGO crystal thermal model

Fig. 4. Schematic of external temperature change

Fig. 5. Coordinate system definition of stage II temperature field

Fig. 6. Construction of BGO crystal thermal circuit model

Fig. 7. Flow of central differential Kalman filtering

Fig. 8. Temperature fitting image of BGO crystal physical properties parameters

Fig. 9. Simulation of BGO crystal temperature field

Fig. 10. Model calculation and simulation comparison of BGO crystal face center point and body center point

Fig. 11. Cooling environment BGO body center point model calculation and simulation comparison

Fig. 12. Temperature-time distribution at each position of the central axis of the BGO crystal

Fig. 13. The analytical formula of the through optical path and the relative error of the simulation

Fig. 14. Comparison of the measured data of the temperature of the center point of the crystal surface and the calculated value of the temperature field model

Fig. 15. BGO crystal internal temperature estimation result

Fig. 16. Photodetector linear response calibration

Fig. 17. The AC and DC components of the sensor output signal in a heating environment

Fig. 18. CDKF estimation results for refractive index n₀

Fig. 19. Optical voltage sensor temperature compensation experimental platform equipment

Fig. 20. Optical voltage sensor temperature compensation experiment platform connection schematic