Fig. 1. Scheme of the ROG based on phase modulation technology

Fig. 2. Common noise types and their suppression techniques in ROG

Fig. 3. ROG based on different modulation techniques^{［38，41-42，44］}

Fig. 4. ROG based on different demodulation techniques^［46-47］

Fig. 5. Three closed loop noise suppression method for RMOG^［48］

Fig. 6. Schematic diagram of resonant gyroscope of Honeywell^［49］

Fig. 7. Experimental setup of the intensity variation noise^［52］

Fig. 8. Some ROGs based on light intensity feedback^［53-55］

Fig. 9. RFOG with two in-line polarizers^［61］

Fig. 10. Schematic of a double Faraday rotation system ^［62］

Fig. 11. WRR structure with single polarization fiber as tail fiber^［63］

Fig. 12. ROG based on a multi-light solution^［65-66］

Fig. 13. ROG for laser frequency locking^{［69，71，73］}

Fig. 14. Challenges and prospects of noise suppression^{［79-80，83-84，86-88，90，94］}