- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Low Noise Φ-OTDR Based on Frequency-Jitter-Free Heterodyne Demodulation Scheme
摘要： In this paper, a low noise Φ-OTDR is proposed which utilizes frequency-jitter-free heterodyne modulation scheme to retrieve the phase variations of Rayleigh backscattered light-waves along a sensing fiber. The heterodyne modulation scheme employs only one acousto-optic modulator (AOM), and thus is immune to the jitter of frequency shift of an AOM. Benefiting from that, the noise level of a Φ-OTDR is reduced. Multiple vibration events occurring simultaneously at different positions along the fiber are experimental restored by the proposed Φ-OTDR. The signal-to-noise ratio of 57.78 dB and the noise level as low as -65.4 dB (re 1rad/sqrt(Hz)) at 1 kHz are achieved.
关键词： heterodyne demodulation,Φ-OTDR,Frequency-jitter-free
更新于2025-09-12 10:27:22
-
Pulse-Width Multiplexing ?-OTDR for Nuisance-Alarm Rate Reduction
摘要： A pulse-width multiplexing method for reducing the nuisance-alarm rate of a phase-sensitive optical time-domain reflectometer (φ-OTDR) is described. In this method, light pulses of different pulse-widths are injected into the sensing fiber; the data acquired at different pulse-widths are regarded as the outputs of different sensors; and these data are then processed by a multisensor data fusion algorithm. In laboratory tests with a sensing fiber on a vibrating table, the effects of pulse-width on the signal-to-noise ratio (SNR) of the φ-OTDR data are observed. Furthermore, by utilizing the SNR as the feature in a feature-layer algorithm based on Dempster–Shafer evidential theory, a four-pulse-width multiplexing φ-OTDR system is constructed, and the nuisance-alarm rate is reduced by about 70%. These experimental results show that the proposed method has great potential for perimeter protection, since the nuisance-alarm rate is significantly reduced by using a simple configuration.
关键词： multisensor data fusion,pulse-width multiplexing,nuisance-alarm rate,φ-OTDR
更新于2025-09-10 09:29:36
-
Performance comparison of combining algorithms for polarization-diversity receiving in phase-sensitive OTDR
摘要： We investigate three different combining algorithms for polarization-diversity receiving in phase-sensitive optical time-domain reflectometry (φ-OTDR) system. The algorithms are equal gain combining(EGC), selective combining(SC) and max-ratio combining(MRC). We compare the performance of the three combining algorithms in three aspects, which are the SNR of the locating signal, the SNR of the recovered vibration signal and the computation cost of the algorithms. The results show that the SC algorithm has a poor locating performance and is unsuitable for locating of the system. The EGC algorithm has the lowest complexity and general locating performance, which can be applied in real-time locating of external vibration. The performance of MRC algorithm is optimal, which is a promising tool in the high SNR intrusion location system. The proper combining algorithms we chosen will contribute to achieving optimal performance and optimal resource allocation of the φ-OTDR system.
关键词： Distributed optical fiber sensor,polarization-diversity combining algorithms,φ-OTDR
更新于2025-09-10 09:29:36