Proposal of external modulation scheme for fiber-optic correlation-domain distributed sensing

Noda, Kohei; Han, Guo‐Zhi; Lee, Heeyoung; Mizuno, Yosuke

doi:10.7567/1882-0786/aaf416

Cited by 18 publications

(18 citation statements)

References 36 publications

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“…Optical reflectometry technologies, including optical time domain reflectometry (OTDR) [ 1 , 2 , 3 , 4 ], optical frequency domain reflectometry (OFDR) [ 5 , 6 , 7 , 8 , 9 ], and optical coherent domain reflectometry (OCDR) [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ], have been widely used in the monitoring of fiber link and distributed sensing applications. The OTDR simply measures the round-trip time of reflection and Rayleigh backscattering (RBS) of the probe pulse.…”

Section: Introductionmentioning

confidence: 99%

“…To simplify the configuration, the reference arm can be replaced by the Fresnel-reflected light of the FUT [ 17 ], or the optical frequency shifter can be removed [ 18 ]. An external modulation scheme using an electro-optic modulator (EOM) was also adopted to overcome the issues caused by internal modulation [ 19 ]. An acousto-optical modulator (AOM) was also adopted for frequency modulation with high sideband band suppression.…”

Section: Introductionmentioning

confidence: 99%

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External Modulation Optical Coherent Domain Reflectometry with Long Measurement Range

Xue

Niu

Shangqing

2021

Sensors

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Optical coherent domain reflectometry (OCDR) can achieve a high spatial resolution that is independent of the bandwidth of the receiver, but the measurement range is usually very limited. Here we propose an external modulation OCDR system, in which a pair of linear frequency-modulated pulses generated by one modulator are employed as the probe pulse and the reference, respectively. The spatial resolution is determined by the frequency modulation range of the pulse, and the measurement speed is boosted by orders because the proposed technology can simultaneously diagnose a section of fiber with each pair of pulses, while only a single point can be accessed at a time in typical OCDR. In the demonstrational experiment, a measurement range of up to 50 km is achieved with a spatial resolution of 1.4 m and a measuring time of less than 30 s.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

External Modulation Optical Coherent Domain Reflectometry with Long Measurement Range

Xue

Niu

Shangqing

2021

Sensors

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“…of the states of polarization (SOPs) of the backscattered lights are basically disturbance factors for such sensors, the input SOPs are often scrambled to mitigate the fluctuations [3][4][5]. Meanwhile, the SOP of the backscattered light has information on the birefringence of the sensing fiber, which is sensitive to external disturbances, such as bending [6], lateral pressure [7], magnetic field [8,9], and twist [10][11][12].…”

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confidence: 99%

Proposal of Polarization Optical Correlation-Domain Reflectometry (POCDR)

Noda

Lee

Nakamura

et al. 2022

J. Lightwave Technol.

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We propose a new scheme for polarization-sensitive distributed fiber-optic sensing, called polarization optical correlation-domain reflectometry (POCDR), and experimentally demonstrate its fundamental operations. In this scheme, the states of polarization (SOPs) of reference lights are controlled so that they are uniformly distributed on the Poincaré sphere using a calibration method, which cancels the effect of unknown birefringence in the fibers used in the system. Then the SOP of spontaneous Brillouin scattering in a sensing fiber is estimated using a least-squares method, by measuring the interference powers for the multiple reference lights with different SOPs. As a pilot demonstration, the SOP transitions along a fiber including a three-paddle polarization controller are measured under different conditions. We also measure the SOP transition of a fiber wound on a bobbin and calculate its polarization beat length, which agrees well with the theoretical value. By exploiting its unique nature called random accessibility, high-speed measurement of the roundtrip birefringence between two arbitrary points in a sensing fiber will be potentially achieved.

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“…By sweeping the modulation frequency, the position of the correlation peak can be scanned along the FUT, and the distributed information of the Brillouin gain spectrum (BGS) and/or the Brillouin frequency shift (BFS) can be obtained. In most of the BOCDA and BOCDR systems reported so far [15][16][17][18][19][20][21][22][23] (with a small number of exceptions [24][25][26]), a direct modulation scheme, in which the laser driving current was directly modulated to achieve optical frequency modulation (FM), was employed because of its simplicity and cost efficiency. However, the direct modulation scheme suffers from inevitable amplitude modulation (AM), which sometimes deteriorates the system performance such as spatial resolution [27,28].…”

mentioning

confidence: 99%

Error compensation in Brillouin optical correlation-domain reflectometry by combining bidirectionally measured frequency shift distributions

Zhu

Noda

Lee

et al. 2021

Appl. Phys. Express

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In standard single-end-access Brillouin optical correlation-domain reflectometry (BOCDR), the systematic error caused by the phase difference between amplitude modulation (AM) and frequency modulation (FM) in the light source can be up to tens of megahertz, causing considerable errors in strain and temperature measurement. In this letter, we develop a new concept of two-end-access BOCDR, in which light is injected into each end of a sensing fiber in turn and the measured results of the Brillouin frequency shift distributions are combined. We numerically show that this configuration can suppress the systematic error caused by the AM-FM phase difference by approximately 90%.

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Proposal of external modulation scheme for fiber-optic correlation-domain distributed sensing

Cited by 18 publications

References 36 publications

External Modulation Optical Coherent Domain Reflectometry with Long Measurement Range

External Modulation Optical Coherent Domain Reflectometry with Long Measurement Range

Proposal of Polarization Optical Correlation-Domain Reflectometry (POCDR)

Error compensation in Brillouin optical correlation-domain reflectometry by combining bidirectionally measured frequency shift distributions

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