Author Affiliations
College of Meteorology and Oceanography, National University of Defense Technology, Changsha, Hunan 410073, Chinashow less
Fig. 1. Structure of interferometric time-division multiplexing sensor array system based on fiber Bragg grating
Fig. 2. PGC-PS demodulation process
Fig. 3. Spectrum characteristics before and after application PGC modulated carrier signal. (a) Before application; (b) after application
Fig. 4. Relationship between high frequency noise and PGC modulation frequency. (a) 50 kHz; (b) 16 kHz ; (c) 10 kHz ; (d) 6 kHz
Fig. 5. Noise demodulation results at different modulation frequencies. (a) White noise; (b) noise with frequency of 1/f; (c) noise with frequency of 1/f2; (d) mixed noise
Fig. 6. Experimental system of 8-fold time-division multiplexed single-mode fiber Bragg grating sensing array
Fig. 7. Measurement results of background phase noise in 8 time-division multiplexed channels
Fig. 8. Measurement results of background phase noise in two time-division multiplexed channels
Fig. 9. Measurement results of background phase noise in four time-division multiplexed channels
Fig. 10. Experimental system of 8 time-division multiplexing polarization-maintaining fiber Bragg grating sensor array
Fig. 11. Measurement results of background phase noise in all polarization-maintaining 8 time-division multiplexing channels
Fig. 12. Relationship between phase noise and PGC modulation frequency at 1 kHz frequency
Ii_DC /mW | C | fPGC /kHz | ϕs(t) /rad | ϕg /rad |
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1+0.01·w | 2.37 | 50,16,10,6 | 5w·cos(2πkt) | (1+0.001·w)π/2 |
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Table 1. Simulation parameters of PGC modulation and demodulation noise aliasing
Parameter | 1 | 2 | 3 | 4 |
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Laser source type | Fiber laser | Fiber laser | Fiber laser | Laser diode | Relative intensity noise of laser at 1 kHz /dB | -120 | -120 | -120 | -110 | N | 8 | 2 | 4 | 8 | Reflectivity /% | 0.6 | 0.6 | 0.6 | 0.1 | Polarization control | PS | PS | PS | All polarization-maintaining | Fiber length of element /m | 58.78 | 39.75 | 18.25 | 40.00 | fAOM /kHz | 192 | 320 | 512 | 400 | fPGC /kHz | 6 | 10 | 16 | 50 |
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Table 2. Main design structure and modulation parameters of 4 sets of fiber Bragg grating sensor array system