Phase-sensitive optical time domain

Phase-sensitive optical time domain reflectometers(-OTDRs) have been widely studied and utilized inindustrial applications for years, due to their sensitivity to various environments.[1−3] To enhance sensitivity and to extend working distance, heterodyne coherence detection is the traditional demodulation schemein OTDRs.[4−7] A narrow linewidth laser is necessaryto guarantee the coherence between the local oscillatorand the Rayleigh scattering, and the linewidth of lasersource decides the sensing distance of heterodyne -OTDRs. The -OTDR based on the Michelson interferometer (MI) or the Mach–Zehnder interferometer(MZI) tests the phase difference between the Rayleighscattering from two sections of fiber.[8] The Michelson or Mach–Zehnder interferometer based on a 3 × 3coupler, which forms a 120∘-phase-difference interferometer, can be used to demodulate phase differencebetween two points whose time difference is equal to the arm delay of the interferometer.[9−11] The common phase detection scheme, known as the differentiate and cross-multiply demodulation scheme, is used to calculate the phase difference.In this Letter, a 120-phase-difference Michelson interferometer based on a 3×3 coupler combined with the phase detection scheme called the inverse transmission matrix demodulation scheme is proposed. The distributed phase along a long fiber is tested by amplifing and filtering the Rayleigh scattering. Due to the fact that the 120-phase-difference interference is the self-interference of the Rayleigh scattering at different locations, the narrow linewidth local sources are unnecessary. In the inverse transmission matrix demodulation scheme, only one equation should be calculated and the transmission parameters of the interferometer could be calibrated, therefore phase information could be obtained and used to reflect the disturbance of fiber effectively. An acoustic signal within the whole human hearing range of 20 Hz–20 kHz is reproduced and a 3 km fiber is monitored accurately

結果 (繁體中文) 1:

相位敏感的光學時域反射計
（-OTDRs）已被廣泛研究，並在利用
工業應用多年，由於它們對各種環境敏感性。[1-3]為了提高靈敏度和延長工作距離，外差相干檢測是傳統的解調方案
中的OTDR [4-7]的窄線寬激光器是必要的。
以保證本機振盪器之間的相干性
和所述瑞利散射，和激光器的線寬
源決定外差的感測距離-
的OTDR。根據邁克爾遜干涉儀（MI）或馬赫-曾德干涉儀中的-OTDR
（MZI）測試瑞利之間的相位差
scattering from two sections of fiber.[8] The Michelson or Mach–Zehnder interferometer based on a 3 × 3
coupler, which forms a 120∘-phase-difference interferometer, can be used to demodulate phase difference
between two points whose time difference is equal to the arm delay of the interferometer.[9−11] The common phase detection scheme, known as the differentiate and cross-multiply demodulation scheme, is used to calculate the phase difference.
In this Letter, a 120-phase-difference Michelson interferometer based on a 3×3 coupler combined with the phase detection scheme called the inverse transmission matrix demodulation scheme is proposed. The distributed phase along a long fiber is tested by amplifing and filtering the Rayleigh scattering. Due to the fact that the 120-phase-difference interference is the self-interference of the
Rayleigh scattering at different locations, the narrow linewidth local sources are unnecessary. In the inverse transmission matrix demodulation scheme, only one equation should be calculated and the transmission parameters of the interferometer could be calibrated, therefore phase information could be obtained and used to reflect the disturbance of fiber effectively.

20Hz到20kHz的整個人類聽覺範圍內的聲信號被再現和3公里光纖被精確地監測

結果 (繁體中文) 2:

相位敏感光學時域反射儀
（-OTDR）在
工業應用多年，由於其對各種環境的敏感性。[1]為了提高靈敏度，延長工作距離，異端相干檢測是傳統的解調方案
在 OTDR 中。[4]7] 需要窄線寬雷射器
保證本地振盪器之間的一致性
和雷利散射，和鐳射的線寬
源決定異位的傳感距離 -
OTDR。基於蜜雪兒森干涉儀 （MI） 或馬赫 -澤恩德干涉儀的 -OTDR
（MZI） 測試雷利之間的相位差異
從光纖的兩個部分散射。[8] 基於3×3的蜜雪兒森或馬赫-澤恩德干涉儀
耦合器，形成120-相位差干涉儀，可用於解調相差
時差等於干涉儀臂延遲的兩個點之間。[9[11] 用於計算相位差的共相檢測方案，稱為區分和交叉乘解解方案。
在本信中，提出了一種基於3×3耦合器的120相差蜜雪兒森干涉儀，結合相位檢測方案，稱為逆透射矩陣解調方案。通過放大和過濾雷利散射來測試長纖維的分散式相位。由於 120 相差干擾是
雷利分散在不同的位置，狹窄的線寬局部源是不必要的。在逆透矩陣解調方案中，只計算一個方程，可以校準干涉儀的傳輸參數，從而獲得相位資訊，並用於反映光纖的擾動有效。

再現整個人類聽力範圍內 20 Hz-20 kHz 的聲學信號，並精確監控 3 km 光纖

結果 (繁體中文) 3:

相敏光時域反射計
（-OTDRs）已經被廣泛的研究和應用於
工業應用多年，由於其對各種環境的敏感性。[1-3]為了提高靈敏度和延長工作距離，外差相干檢測是傳統的解調方案
在OTDRs中[4-7]需要窄線寬雷射器
保證本振子之間的相干性
瑞利散射和雷射的線寬
光源决定外差的傳感距離-
OTDRs公司。基於邁克爾遜干涉儀（MI）或馬赫-曾德爾干涉儀的OTDR
（MZI）測試瑞利之間的相位差
兩段光纖的散射。[8]基於3×3的邁克爾遜或馬赫-曾德爾干涉儀
構成120∘-相位差干涉儀的耦合器可用於解調相位差
在時間差等於干涉儀臂延遲的兩點之間。[9-11]使用公共相位檢測方案（稱為差分和交叉乘法解調方案）來計算相位差。
本文提出了一種基於3×3耦合器的120相位差邁克爾遜干涉儀，並結合相位檢測方案&逆傳輸矩陣解調方案。通過對瑞利散射的放大和濾波，測試了沿長光纖的分佈相位。由於120相位差干擾是
瑞利散射在不同位置，窄線寬的局部光源是不必要的。在逆傳輸矩陣解調方案中，只需計算一個方程，即可對干涉儀的傳輸參數進行標定，從而獲得相位資訊，有效地反映光纖的擾動。
在20赫茲到20千赫的整個人類聽覺範圍內的聲音訊號被再現，並且3公里的光纖被精確監控