Abstract The integration of high-speed optical communication and distributed sensing could bring intelligent functionalities to ubiquitous fibre networks, such as urban structure imaging, ocean seismic detection, safety monitoring underground embedded pipelines. This work demonstrates a scheme integrated in an (ISAC-OF) using the same wavelength channel for simultaneous data transmission vibration sensing. not only extends functionality system, but also improves its performance. A periodic...

An adaptive image restoration algorithm based on 2-D bilateral filtering has been proposed to enhance the signal-to-noise ratio (SNR) of intrusion location for phase-sensitive optical time domain reflectometry (Φ-OTDR) system. By converting spatial and information Φ-OTDR traces into image, can smooth noise preserve useful signal efficiently. To simplify algorithm, a Lorentz function is adopted replace original Gaussian function, which higher practicability. Furthermore, an parameter setting...

Phase-sensitive optical time domain reflectometry (Φ-OTDR) realizes quantitative measurement of the dynamic strain employing phase demodulation. Unfortunately, it is difficult to measure large with conventional Φ-OTDR due restriction unwrapping algorithm. In this work, an approach based on two-wavelength probe proposed and demonstrated improve measurable range in Φ-OTDR. By utilizing difference between two phases acquiring different lasers, can be recovered. experiments, strains peak values...

An approach of phase-shift transform is proposed and demonstrated to suppress the interference fading in phase sensitive optical time domain reflectometry (Φ-OTDR). The executed digital complicated frequency modulation not required. operation principle carefully analyzed a signal with complementary amplitude can be obtained this method. Through synthesizing signals, false phases corrected. Benefiting from flexibility approach, multiple transforms are implemented make sure that all retrieved...

A novel measurement scheme for multiple high-frequency vibrations has been demonstrated by combining phase-sensitive optical time domain reflectometry (Ф-OTDR) and Mach-Zehnder interferometer (MZI) based on frequency division multiplexing. The light source is directly launched into the MZI structure, while it was modulated an acoustic modulator (AOM) with a shift of 200 MHz Ф-OTDR part. vibration obtained demodulating interference signal position located system. spatial resolution 10m over 3...

Phase-sensitive optical time domain reflectometry (Ф-OTDR) attracts much attention due to its capability of telling the type and position an intrusion simultaneously. In recent decades, coherent Ф-OTDR has been demonstrated realize long-distance detection. For Ф-OTDR, there are three typical demodulation schemes in reported studies. However, they still cannot real-time monitoring satisfy practical demands. A simple effective method based on self-mixing put forward demodulate beat signal...

Backscattered lightwaves from an optical fibre are used to realise distributed optic sensing (DFOS) systems for measuring various parameters.Rayleigh, Brillouin, and Raman backscattering provide different sensitivities measurands have garnered the attention of researchers.A system combining three principles above can effectively separate measured strain temperature completely as well measurements both dynamic static parameters.However, combined is extremely complicated if independent each...

A phase demodulation algorithm in phase-sensitive optical time domain reflectometry (φ-OTDR) with self-interference balance detection is proposed. With a simple differentiate-and-cross-multiply (DCM) operation to acquire the perturbation waveform, and further second-order compensate amplitude fluctuation of phase, can be extracted accurately. The structure equivalently achieve function dual-pulse detection, but avoid negative impact common-mode noise difference between dual pulses on...

In phase-sensitive optical time domain reflectometry ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Φ</mml:mi><mml:mtext>-</mml:mtext><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">O</mml:mi><mml:mi mathvariant="normal">T</mml:mi><mml:mi mathvariant="normal">D</mml:mi><mml:mi mathvariant="normal">R</mml:mi></mml:mrow></mml:math> ), false phase peaks caused by interference fading have been observed experimentally;...

In order to cancel phase fluctuation induced Brillouin gain spectrum (BGS) and (BPS) distortions, a new scheme with cancellation (PFC) is proposed realize precise BGS BPS measurements in coherent BOTDA sensors. We present comprehensive theoretical analysis about the effect of on shape BPS, further design experimental setup fully measurement errors. our scheme, two signals sent into in-phase/quadrature (I/Q) demodulator are almost same except for additional amplitude amplification shift by...

A novel multi-frequency decomposition (MFD) scheme is proposed to achieve a fading-free phase-sensitive optical time-domain reflectometry ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Phi $ </tex-math></inline-formula> -OTDR). By performing short-time Fourier transform (STFT) on the detected signal, spectrum contents of normal probe pulse can be fully utilized and decomposed in time-frequency domain...

Stimulated Brillouin scattering (SBS)-based distributed fiber optic sensing technique has found pervasive applications in measurement of real-world environmental variables. Its capability, however, is affected by the tradeoff between distance and spatial resolution. Herein, we propose experimentally verify a wideband amplification (WBA)-boosted BOCDA to achieve high resolution longer distance. The WBA generated exploiting phase-uncorrelated SBS process pump probe waves. Through WBA, pulses...

A pulse width modulation (PWM) Brillouin amplification has been proposed and demonstrated to improve the signal-to-noise ratio (SNR) sensitivity of phase-sensitive optical time domain reflectometry (Ф-OTDR) especially for far end a sensing fiber. In logarithmic unit, arbitrary gain distribution can be realized with customizable PWM function. The is adjustable by tuning parameters. To prove concept, three typical distributions including up-ramp sawtooth, sine triangle have achieved...

In order to optimize the coherent Brillouin optical time domain analysis (BOTDA) sensor for more effective chromatic dispersion (CD) suppression, single-sideband intensity-modulated probe (IMP) light is utilized. Obvious gain spectrum distortion due CD observed in double-sideband IMP case successfully cancelled. Meanwhile, frequency preshift local generation other BOTDA sensors that have been reported recently can be avoided our scheme, resulting a reduction system complexity. On hand,...

The measurement accuracy of a Brillouin optical time domain analysis (BOTDA) fiber sensor is determined by the signal-to-noise ratio (SNR) received sensing signal. Here, new hybrid aperiodic coding method proposed to improve SNR. In method, two pre-discovered short seed codes (SA-codes) are used construct code (HA-code) in nested way. HA-code inherits good denoising capabilities SA-codes and features high gain. proof-of-concept experiment, SNR improvement up 8 dB obtained, which improves...

A hybrid aperiodic-coded Brillouin optical correlation domain analysis (HA-coded BOCDA) fiber sensor is proposed to achieve long-range high-spatial-resolution distributed measurement. It found that high-speed phase modulation in the BOCDA actually forms a special energy transformation mode. This mode can be exploited suppress all detrimental effects parasitized pulse coding-induced cascaded stimulated scattering (SBS) process and thereby enable HA-coding reach its full potential improve...

A new and improved synthetic route to vortioxetine hydrobromide is established on a hectogram scale through three simple steps in 63% yield with 99% purity (HPLC). The key step the cyclization of piperazine ring final step. Purification methods for intermediates involved are given.

Furnace temperature is an important indicator to control and optimize the Municipal Solid Wastes Incineration (MSWI) process. However, limited by environment instruments, it difficult measure furnace online accurately. In this paper, a TS fuzzy neural network utilized design prediction model in MSWI process, trying obtain real-time accurate measurement of temperature. First, mechanism process introduced brief. Then, structure training method TS-fuzzy-neural-network-based details, which helps...

In this Letter, a chirped-pulse conversion algorithm (CPCA) is proposed to convert normal probe pulse into an equivalent chirped by convolving chirp factor on the received signal in coherent phase-sensitive optical time-domain reflectometry ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi mathvariant="normal">Φ</mml:mi> </mml:math> -OTDR). With algorithm, Rayleigh interference pattern (RIP) demodulation once applied -OTDR can be adopted quantify dynamic...

The erbium-doped-fiber-amplifier (EDFA), generally served as a pre-amplifier, could effectively raise the signal-to-noise ratio (SNR) of Brillouin optical time-domain analysis (BOTDA) sensor. However, it also induces distortion in gain spectrum and frequency shift measurement errors due to slow transient effect (STE) coded-BOTDA. We propose distributed depletion mapping (DDM) method overcome such an effect. A continuous light wave with particular wavelength is injected map STE-induced...

A scheme combining phase-sensitive optical time domain reflectometry and Mach-Zehnder interferometer based on frequency division multiplexing has been demonstrated. The spatial resolution of 10m over 3Km sensing fiber vibration 40 KHz are obtained.