Da-Peng Zhou
University of Ottawa
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Da-Peng Zhou.
Optics Express | 2012
Da-Peng Zhou; Zengguang Qin; Wenhai Li; Liang Chen; Xiaoyi Bao
The distributed vibration or dynamic strain information can be obtained using time-resolved optical frequency-domain reflectometry. Time-domain information is resolved by measuring Rayleigh backscatter spectrum in different wavelength ranges which fall in successive time sequence due to the linear wavelength sweep of the tunable laser source with a constant sweeping rate. The local Rayleigh backscatter spectrum shift of the vibrated state with respect to that of the non-vibrated state in time sequence can be used to determine dynamic strain information at a specific position along the fiber length. Standard single-mode fibers can be used as sensing head, while the measurable frequency range of 0-32 Hz with the spatial resolution of 10 cm can be achieved up to the total length of 17 m.
Optics Letters | 2012
Meng Pang; Shangran Xie; Xiaoyi Bao; Da-Peng Zhou; Yuangang Lu; Liang Chen
We report a single frequency lasing phenomenon with a narrow linewidth of ~3 kHz in cascaded fiber that is composed of three types of low-loss communication fibers. The Rayleigh scattering of the Brillouin Stokes light created in the middle fiber section along both directions is enhanced by the other two fiber sections. When the Brillouin gain of the middle fiber exceeds the effective loss of the Brillouin stokes light in a roundtrip, a narrow linewidth lasing is observed on the top of the Brillouin spectrum line of the middle fiber. To the best of our knowledge, it is the first report on Rayleigh scattering-assisted Brillouin lasing with single frequency and narrow linewidth in cascaded low-loss communication fibers.
Optics Express | 2011
Da-Peng Zhou; Yongkang Dong; Liang Chen; Xiaoyi Bao
We investigate the Brillouin dynamic grating generation and detection process in polarization-maintaining fibers for the case of continuous wave operation both theoretically and experimentally. The four interacting light waves couple together through the material density variation due to stimulated Brillouin scattering. The four coupled equations describing this process are derived and solved analytically for two cases: moving fiber Bragg grating approximation and undepleted pump and probe waves approximation. We show that the conventional grating model oversimplifies the Brillouin dynamic grating generation and detection process, since it neglects the coupling between all the four waves, while the four-wave mixing model clearly demonstrates this coupling process and it is verified experimentally by measuring the reflection of the Brillouin dynamic grating. The trends of the theoretical calculation and experimental results agree well with each other confirming that the Brillouin dynamic grating generation and detection process is indeed a four-wave mixing process.
Sensors | 2013
Da-Peng Zhou; Wenhai Li; Liang Chen; Xiaoyi Bao
A distributed optical fiber sensor with the capability of simultaneously measuring temperature and strain is proposed using a large effective area non-zero dispersion shifted fiber (LEAF) with sub-meter spatial resolution. The Brillouin frequency shift is measured using Brillouin optical time-domain analysis (BOTDA) with differential pulse-width pair technique, while the spectrum shift of the Rayleigh backscatter is measured using optical frequency-domain reflectometry (OFDR). These shifts are the functions of both temperature and strain, and can be used as two independent parameters for the discrimination of temperature and strain. A 92 m measurable range with the spatial resolution of 50 cm is demonstrated experimentally, and accuracies of ±1.2 °C in temperature and ±15 με in strain could be achieved.
IEEE Photonics Technology Letters | 2013
Yuangang Lu; Zengguang Qin; Ping Lu; Da-Peng Zhou; Liang Chen; Xiaoyi Bao
A novel distributed strain and temperature measurement method based on Brillouin beat spectrum (BBS) in a complex index profile fiber are proposed. The BBS corresponds to the optical interaction of different acoustic modes. For a large-effective-area fiber (LEAF), the first peak of BBS is contributed by the first and second acoustic modes, while the second peak in BBS is contributed by the first and third accoustic modes. Through determining power changes in the peaks of BBS due to strain and temperature variation along a LEAF, the distributed strain and temperature can be measured by the homodyne Brillouin optical time-domain reflectometry (BOTDR) without scanning the Brillouin spectrum. The strain and temperature at the end of a 4.5-km LEAF are measured at 3-m spatial resolution in 140 s.
Applied Optics | 2016
Da-Peng Zhou; Liang Chen; Xiaoyi Bao
Distributed dynamic strain measurement based on optical frequency-domain reflectometry is proposed. The technique makes use of the wide scanning range of a tunable laser source in a short sweeping time, and subdivides the overall spectrum into narrower frequency windows. The advantage of subdividing the laser spectral range is to improve the measurement uncertainty induced by the laser wavelength difference between repeated scans. The noise-limited dynamic strain resolution is investigated experimentally, indicating that a minimum detectable strain is less than 200 nε for a spatial resolution of 20 cm. By measuring the subdivided spectral shifts in the time sequence along the sensing fiber, the dynamic strain can be properly quantified over a 30 m measurement range for a highest sampling rate of up to 50 Hz.
Journal of The Optical Society of America B-optical Physics | 2013
Da-Peng Zhou; Liang Chen; Xiaoyi Bao
Polarization-decoupled four-wave mixing (FWM) based on stimulated Brillouin scattering (SBS) in a polarization-maintaining fiber is studied both theoretically and experimentally. We show the difference between Brillouin-enhanced FWM, which was studied a long time ago, and the Brillouin dynamic grating that was proposed in recent years. Under undepleted pump approximation, an analytical solution is given for the coupled equations, showing that a net phase-matching condition is dependent on pump power and frequency detuning from the Brillouin frequency. Experimental investigation of this net phase-matching condition provides a method to measure the spectral change in the refractive index that is responsible for the slow light effect based on SBS. Small refractive index changes (on the order of 10−8) versus frequency detuning can be determined experimentally.
Optics Express | 2016
Meiqi Ren; Da-Peng Zhou; Liang Chen; Xiaoyi Bao
The leakage light of optical pulses due to finite extinction ratio (ER) of an electro-optic modulator (EOM) leads to Rayleigh backscattered noises over the entire fiber length, and limits spatial resolution and sensing range in phase-sensitive optical time-domain reflectometry (Φ-OTDR). Two configurations are proposed to improve the ER of optical pulses for better spatial resolution over long sensing length. With ER of 55 dB using a nonlinear optical loop mirror, we achieved 2 m spatial resolution over 8.4 km sensing length; while with ER of 60 dB obtained by two cascaded EOMs, we can achieve a 1 m spatial resolution over the same range. Experimental results and analysis show that leakage of the optical pulses acts as a noise floor, which limits the highest spatial resolution over the same sensing range.
Journal of Lightwave Technology | 2017
Xiaoyi Bao; Da-Peng Zhou; Chams Baker; Liang Chen
Distributed acoustic sensors provide a powerful instrumentation for ultrasound testing to identify the internal crack and deformation with the location for assessing structural conditions and predicting the potential structural failure. This paper provides a tutorial review of the milestones leading to the development of the distributed acoustic sensor based on Rayleigh back scattering. It offers discussion on basic principles, optical configurations and system design requirement, various detection schemes, performance limitations and applications for the maximum measurable frequency, minimum detectable strain and highest spatial resolution. A final comment on the prospects of the further developments is presented.
Archive | 2012
Yongkang Dong; Hongying Zhang; Da-Peng Zhou; Xiaoyi Bao; Liang Chen
There is an increasing interest over recent years in Brillouin gratings in optical fibers due to their applications in optical storage (Cao et al., 2008; Kalosha et al., 2008; Zhu et al., 2007), distributed sensing (Dong et al., 2009; Song et al., 2009, 2010; Zou et al., 2009a, 2009b, 2010), optical delay line (Song et al., 2009), and birefringence characterization of polarizationmaintaining fibers (Dong et al., 2010). Generally, a Brillouin grating is generated by using two counter-propagating pump waves through stimulated Brillouin scattering (Song et al., 2008). A Brillouin grating is formed by a moving periodically modulated refractive index associated with an acoustic wave, which is created by two pump waves through electrostriction effect. Compared with conventional fiber Bragg gratings, the Brillouin gratings have two unique features: one is that it is a moving grating, which can produce a Brillouin frequency shift on the reflected light with respect to the probe wave, and the other is that it has a lifetime (~10 ns in a silica fiber) for its existence after removing the two pump waves.