Optical Fiber Vibration Sensor Using Least Mean Square Error Algorithm

Abstract

In order to enhance the signal-to-noise ratio (SNR) of a distributed optical fiber vibration sensor based on coherent optical time domain reflectometry (COTDR), a high extinction ratio cascade structure of an acousto-optic modulator and semiconductor optical amplifier is applied. The prior time-frequency analysis and least mean square error algorithm are adopted in the COTDR system for amplitude demodulation and phase demodulation, in order to improve the SNR by noise elimination. The experimental results show that the adaptive filter based on the least mean square error algorithm could realize the extraction of a three-order sinusoidal harmonic signal from strong background noise along the optical fiber and the SNR improvement from 10.4 dB to 42.2 dB. The proposed demodulation algorithm is suitable for the detection of vibration signals with characteristic frequencies in the application of acoustic fault diagnosis for electromechanical devices.

Research Progress in Distributed Acoustic Sensing Techniques

“…In 2020, Jin et al first adopted an acousto-optic modulator cascaded with a semiconductor optical amplifier to improve the extinction ratio of the system, and later used time-frequency analysis and minimum mean square error algorithms for amplitude demodulation and phase demodulation to improve the SNR of the system to 42.2 dB [66] (Figure 16). Due to their popularity, artificial intelligence (AI) and machine learning (ML) can be applied to DAS systems to improve the system SNR.…”

Scientific Applications of Distributed Acoustic Sensing: State-of-the-Art Review and Perspective

“…Distributed fiber sensors are used to measure the distribution of temperature [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], stress/deformations [ 22 , 23 , 24 ], or vibro-acoustic properties [ 25 , 26 , 27 , 28 , 29 , 30 ] of various objects. The last application allows more information about the investigated object to be obtained in contrast to the static measurement of temperature or stress.…”

Recent Advances in Chitosan-Based Systems for Delivery of Anticancer Drugs

“…The methods proposed in the literature include (but are not limited to); separate and moving averaging method [4], wavelet de-noising method [12], Sobel operators [13], use of dual-pulse phase modulated probe [14], Fourier transform method [15], Hilbert-Huang transform method [16], adaptive filtering [17], phase-shifted double pulse method [18], use of chirped-pulse [19], spectrum extraction and remix (SERM) method [20], and least mean square error (LMSE) adaptive filter algorithm [21]. All these efforts, each with their different complexity, cost, and computational load, can be categorized as enhancement methods at the interrogator side.…”