US 11,867,540 B2
Brillouin optical time domain reflectometer with ultra-high spatial resolution based on bipolar differential phase encoding
Linghao Cheng, Guangdong (CN); Baiou Guan, Guangdong (CN); Xiangjie Ma, Guangdong (CN); and Jinding Zhu, Guangdong (CN)
Assigned to Guangdong Brillinnova Technology Co., Ltd., Zhuhai (CN)
Filed by Guangzhou Brillinnova Technology Co., Ltd., Guangdong (CN)
Filed on Jun. 17, 2022, as Appl. No. 17/842,826.
Application 17/842,826 is a continuation of application No. PCT/CN2020/070085, filed on Jan. 2, 2020.
Claims priority of application No. 201911402178.8 (CN), filed on Dec. 30, 2019.
Prior Publication US 2022/0316922 A1, Oct. 6, 2022
Int. Cl. G01D 5/353 (2006.01)
CPC G01D 5/35364 (2013.01) 9 Claims
OG exemplary drawing
 
1. A Brillouin optical time domain reflectometer with an ultra-high spatial resolution based on bipolar differential phase encoding, comprising:
a narrow-linewidth laser configured to emit a linear polarized laser;
a polarization maintaining coupler configured to divide the linear polarized laser into light of two paths of light, wherein the light of one path is transmitted to a Mach-Zehnder modulator for phase modulation, and the light of the other path is transmitted to a coherent optoelectronic receiver as a local oscillator light source;
a differential encoder configured to perform differential encoding on an original encoding sequence, wherein the original encoding sequence comprises a first encoding sequence and a second encoding sequence, the first encoding sequence and the second encoding sequence are two groups of encoding sequences, and polarities thereof are opposite to each other;
the Mach-Zehnder modulator configured to perform phase modulation on a phase of the linear polarized laser based on an encoding sequence obtained by the performing differential encoding on the original encoding sequence, and output an optical pulse;
an optical circulator and a sensing fiber, wherein the optical circulator is configured to input the optical pulse into the sensing fiber, and receive Brillouin scattering light returned by the sensing fiber;
the coherent optoelectronic receiver configured to perform optoelectronic mixing coherent receiving on the local oscillator light source and the Brillouin scattering light, to obtain a microwave signal, wherein the microwave signal comprises a Stokes signal and an anti-Stokes signal;
a sideband demultiplexer configured to perform signal separation of the Stokes signal and the anti-Stokes signal in the microwave signal, and send the Stokes signal and the anti-Stokes signal to a result measurement module; and
the result measurement module configured to calculate a first instantaneous frequency and a second instantaneous frequency respectively based on the Stokes signal and the anti-Stokes signal, and configured to calculate a final measurement result based on the first instantaneous frequency and the second instantaneous frequency.