Distributed Brillouin fiber sensing, based on the linear relationship between frequency shift (BFS) and physical quantities applied to sensing fibers, has found numerous applications in past few decades. Recently, various advanced image denoising methods have been used for performance enhancements sensors. Yet, even though these do significantly remove noises contained raw data, BFS measurement uncertainty is not reduced–the newly introduced appears redundant with conventional signal...

The performance of unipolar unicolor coded Brillouin optical time-domain analysis (BOTDA) is evaluated based on both Simplex and Golay codes.Four major detrimental factors that limit the system performance, including decoded-gain trace distortion, coding pulse power non-uniformity, polarization pulling higher-order non-local effects, are thoroughly investigated.Through theoretical an experimental validations, solutions optimal design conditions for BOTDA clearly established.First, a...

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...

Standard single mode fiber that normally used in Brillouin optical time domain analysis sensors typically has only one Brilllouin gain peak (BGP), and its central frequency [i.e., shift (BFS)] can be affected by both temperature strain, which gives rise to strain cross sensitivity. In this paper, we propose a new method realize discrimination, for the first best of our knowledge, using commercial dispersion compensating (DCF) two BGPs located around 9.536 10.052 GHz, respectively. The peaks...

Coherent Brillouin optical time domain analysis (BOTDA) sensing system with intensity modulated local (IML) light and fast IQ demodulation is proposed demonstrated. IML instead of phase (PML) utilized to reduce the coherent multiple sidebands induced noises. A spatial resolution 3-m ± 1.8°C temperature accuracy at far end fiber are obtained over 40-km distance.

An approach to eliminating the effect of polarization pulling in Golay-coded Brillouin optical time domain analysis (BOTDA) fiber sensor by employing division multiplexing (PDM) pulse coding is presented. Three different schemes, including switching, scrambling, and PDM are implemented compared. Experimental results indicate that sensing stability enhanced ~2.5 times using proposed scheme.

Different approaches to implement unipolar Golay coding in Brillouin optical time-domain analysis based on a differential pulse pair (DPP) are investigated. The points out that dedicated post-processing procedures must be followed secure the sharp spatial resolution associated with DPP method. Moreover, novel hybrid Golay-DPP scheme is proposed, offering 1.5 dB signal-to-noise ratio improvement respect traditional coding, while halving measurement time, constituting 3 overall gain...

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,...

We propose a scheme of radio-over-fiber (RoF) network supporting the simultaneous transmission radio frequency identification (RFID), Wi-Fi, and ZigBee services. All services share same optical transmitter receiver to reduce complexity. Error vector magnitude (EVM) values 0.36%, 1.23%, 0.25% can be achieved in downlink for RFID, WiFi, signals, respectively. The corresponding EVM uplink are 0.37%, 1.78%, 0.29%, is verified over 2 km RoF link where master nodes communicate normally with...

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 phase fluctuation cancellation approach for anonymous microwave signal transmission over fiber link is proposed and demonstrated. Unlike most previous schemes that used active systems, our proposal suitable passive systems by utilizing the optical feedback electrical phase-locking. Experimental results show drifts of 7.7-ps, 54-ps 96-ps (RMS value) 2.45-GHz signals could be reduced to 3.1-ps, 3.8-ps 8.5-ps after 1-km, 10-km 25-km SMF an eight-hour period, respectively. Overall system...

Precise time-difference detections among different radars in uplink radar arrays require ultrastable phase transfer bidirectional analog optical fiber links. We propose and demonstrate a scheme based on passive frequency mixing to satisfy this requirement which two continue wave (CW) radio (RF) signals after passing through double-path of the transport are utilized for dynamic fluctuation cancellation downlink, respectively. Our has capabilities stable transfers both CW pulsed RF signals....

Minimizing phase fluctuation along passive analog fiber link is proposed and experimentally demonstrated. By utilizing three different optical wavelengths, we could significantly reduce the effect of coherent Rayleigh noise (CRN). In addition, a phase-locked loop employed for dynamic compensation. The RMS jitter within two-hour period reduced to ~1.7131 ps over 40-km link.

The Brillouin collision rate in a optical correlation domain analysis fiber sensor is ultimately limited by the sensing length, which restricts single point sampling dynamic strain measurement. Here, time-gated long-phase-sequence-coded pump method proposed to overcome this limitation. only phonon lifetime, since it governs building and decaying time of acoustic wave. For length <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD">...

A pulse-coded Brillouin optical time domain analyzer (BOTDA) so far uses the single-sideband photo detection. Here, thanks to a specially designed gain extraction scheme, dual-sideband balanced detection is successfully employed in BOTDA. Compared with detection, can effectively eliminate common-mode noises existing two sidebands of commonly used probe. In addition, signal-to-noise ratio (SNR) at fiber end be enhanced by 1.5 dB. The benefits are experimentally demonstrated 117.46-km...

A Brillouin gain fluctuation elimination scheme based on a hybrid polarization pulling and pushing effect (HPPP) is proposed experimentally demonstrated in Golay-coded optical time domain analysis (BOTDA) fiber sensor. The reveals that, due to the non-negligible probe state of (SOP) deviation caused by or effect, effectiveness eliminating using switch significantly degraded. Nevertheless, when Stokes anti-Stokes components separately interact with orthogonal pumps, SOP evolution component...

The employment of coherent detection in a Brillouin optical time domain analysis (BOTDA) fiber sensor brings benefits, including signal-to-noise ratio enhancement, non-local effect reduction, and sensing speed improvement. Recently, it was found that the performance coherent-detection BOTDA suffers from phase fluctuations introduced by group delay jitter. Here, we propose fluctuation cancellation approach based on subcarrier multiplexing. In proof-of-concept experiment, stability for...

Firstly, Erbium-doped fiber amplifier (EDFA) served as pre-amplifier may distort Brillouin gain spectrum (BGS) in coded optical time domain analysis sensor. Here, we found that the EDFA has negligible impact on shape of phase (BPS). Experimental results show a ∼5.4 MHz frequency shift error caused by been avoided using BPS instead BGS. Secondly, after eliminating fluctuation fiber, combination Golay coding and coherent detection realized.

An approach for reducing chromatic dispersion (CD) induced Brillouin gain spectrum (BGS) distortion and measurement instabilities in coherent optical time domain analysis (BOTDA) sensing systems is proposed experimentally demonstrated. By utilizing intensity modulated probe (IMP) instead of phase (PMP), performance obviously improved. Reduction ~6-MHz decoding error caused by the CD BGS achieved frequency shift (BFS) along whole 40-km distance. Enhanced system stabilities are demonstrated...

The dynamic sampling rate of Brillouin optical time domain analysis (BOTDA) is limited by fiber length. For breaking through this limit, a collider (BOTDC) proposed and experimentally demonstrated. In BOTDC, employing frequency-hopping pump probe waves, sensing information-crosstalk between adjacent pulses avoided even though the pulse interval shorter than round-trip flight in fiber. experiment, periodic mechanical vibrations with 19.75 Hz fundamental frequency 39.49 harmonic are measured...

Conventional Brillouin optical time-domain analyzer (BOTDA) with a frequency-modulated probe (FMP) could avoid non-local effects, while still suffering from the acoustic crosstalk between different frequencies. The induced frequency shift (BFS) measurement errors over whole sensing fiber link reduce system certainty subsequently. A BOTDA scheme bidirectional (BFMP) is proposed to overcome such an effect. It utilizes BFMP generate of same magnitude and opposite direction compensate each...

A Brillouin phase spectra (BPS) demodulation approach in optical time-domain analysis (BOTDA) based on to intensity conversion is proposed and demonstrated. By utilizing the cascaded modulation of probe light coherent detection a symmetric double-sidebands BOTDA, shift transferred into signal so that it can be recovered with simple envelope detection. Moreover, measurement accuracy significantly improved by reduction noise caused fiber transmission. 2-m spatial resolution over 39.1-km 0.7 °C...