Fig. 1. On line fabrication system of grating array ^[6]

Fig. 2. Grating array spectra. (a) Synthetic interferometry^[8]; (b) mask method^[9]

Fig. 3. Demodulation principle of grating array based on double SOA^[11]

Fig. 4. Principle diagram of distributed vibration sensing based on grating array and 3×3 coupler algorithm ^[18]

Fig. 5. Temperature monitoring system of air-cooled island based on grating array sensing technology

Fig. 6. Fire monitoring system for cable corridor^[21]. (a) Arrangement of sensing optical cable; (b) demodulation principle of grating array

Fig. 7. Temperature curves of all measuring points at different moments^[21]

Fig. 8. Distributed vibration monitoring system based on grating array sensing technology^[22]. (a) Schematic of vibration cable laying; (b) system architecture

Fig. 9. System external intrusion and vibration signal recognition. (a) Crusher test scenario; (b) vibration curves at different operating conditions

Fig. 10. Oil well monitoring system based on grating array sensing technology. (a) Oil well monitoring test scenario; (b) distributed temperature monitoring curves

Fig. 11. Vibration signals of optical cable at different depths when oil well wall is knocked. (a) Being suspended at 10 m; (b) being suspended at 480 m; (c) being close to shaft wall at 10 m; (d) being close to shaft wall at 480 m