使用瑞利反向散射振幅同步测量FMF中的MDL和DMGD

176 浏览量更新于2024-08-27 收藏 5.96MB PDF 举报

"这篇文章是关于在光纤中同时测量多模干扰(MDL)和模式群延迟差(DMGD)的研究论文，发表在2019年4月的《IEEE Photonics Journal》第11卷第2期。作者包括刘峰、胡桂军、陈伟城、陈粗光、宋丛丛和陈嘉科，均来自吉林大学通信工程学院。该研究利用瑞利反向散射振幅的分析来实现这一创新性的测量方法。" 在光纤通信领域，多模光纤(FMF, Multimode Fiber)由于其较高的数据传输带宽和较低的成本，被广泛应用于短距离通信系统。然而，FMF中存在的两个主要问题——多模干扰(MDL, Mode Division Crosstalk)和模式群延迟差(DMGD, Differential Mode Group Delay)——会严重影响信号质量，降低系统的性能。MDL是指不同模式之间的相互干扰，而DMGD则指的是不同模式在光纤中传播速度的差异导致的信号延迟。本研究提出了一种新的方法，即通过分析瑞利反向散射振幅来同时测量MDL和DMGD。瑞利反向散射是光纤中的一种常见现象，当光在光纤中传播时，部分光能量会以散射的形式返回，形成可检测的信号。通过对这些返回信号的精细分析，可以揭示光纤内部模式的行为，从而获取MDL和DMGD的信息。文章详细阐述了实验设置和数据处理步骤。首先，他们引入一个特定的光源进入FMF，产生包含多种模式的光脉冲。然后，利用光时域反射仪(OTDR, Optical Time-Domain Reflectometer)记录瑞利反向散射信号。通过分析这些信号的幅度变化和时间分布，研究人员能够区分不同模式的散射特性，进而计算出MDL和DMGD的值。这种方法的优势在于，它不需要复杂的光学设备或复杂的信号处理技术，而是依赖于现有的OTDR技术，这使得在实际应用中实施起来更为便捷和经济。此外，通过同时测量MDL和DMGD，该方法有助于优化光纤系统设计，提高通信效率，降低误码率。这篇研究论文为理解和解决多模光纤中的关键问题提供了一个实用的解决方案，并对光纤通信领域的理论研究和工程实践具有重要意义。该研究得到了相关科研基金的支持，并遵循了IEEE的版权政策，允许学术研究和个人用途的翻译和内容挖掘，但任何形式的重新发布和分发都需要获得IEEE的许可。

IEEE Photonics Journal Simultaneous Measurement of MDL and DMGD in FMFs

the FMF designing scheme, characterizing FMFs accurately is of great signiﬁcance. Efﬁcient

techniques that can measure MDL and DMGD conveniently and precisely become an imperative

requirement.

Several techniques for measuring the DMGD in FMF have been proposed, such as optical

low-coherence interferometry (OLCI) technique [9], time-of-ﬂight (TOF) method [10] and spectral

interferometric technique [11]. However, the complicated experimental setups or expensive equip-

ment are required for both the TOF and OLCI, and thus may not be easily accessible. The spectral

interferometric method has a limit to the length of reference arm, which is difﬁcult to measure the

impair m ent parameter of a long FMF. Recently, the microwave-photonic, electrical spectral inter-

ferometry, and coherent-detection-based method with some sophisticated algorithms techniques

[12]–[15] have been demonstrated for characterizing FMFs with good accuracy, which might not be

cost-effective. In terms of MDL measurement, it is essential to separate the propagating modes.

The MDL is always measured with cutback or insertion methods combining mode multiplexers or

mode converters, such as mode couplers or phase plates [16]. But these methods are destructive.

Therefore, some new techniques should be researched to characterize the property of a long FMF

installed in the large-capacity MDM transmission systems. Recently, nondestr uctive technique for

measuring the mode coupling (MC) in the FMFs and multi-core ﬁbers (MCFs) has been proposed

using synchronous multi-channel optical time domain reﬂectometry (OTDR) [17], [18]. Meanwhile,

the bidirectional OTDR technique has been adapted for FMFs or MCFs to measure mode ﬁeld di-

ameter (MFD) distribution, relative-index difference, chromatic dispersion (CD) and so on [19]–[21].

However, there have been few reports on OTDR technique for measuring the MDL or DMGD in

FMFs, especially for simultaneous measurement of above two impairments.

In this paper, we propose and experimentally demonstrate method for simultaneously measuring

the MDL and DMGD in the FMFs. The MDL and DMGD can be simultaneously measured with

the proposed method based on analyzing the Rayleigh backscattering amplitudes obtained using

a nondestructive measurement system. The measured MDL and DMGD in 3-mode ﬁber are about

0.186 dB and 3.581 ps/m between LP

and LP

11a

, 0.157 dB and 3.604 ps/m between LP

and

11b,

respectively. The experimental results show that the values obtained with the proposed

method agreed well with that obtained with the conventional transmission and TOF methods,

respectively. Moreover, the proposed scheme is scalable to measuring ﬁbers with a large number

of modes.

The rest of the paper is organized as follows: Section 2 discusses the principle for simultaneous

measurement of MDL and DMGD in FMF. In Section 3, the measurement performance of our

proposed method is veriﬁed by experiment, and then we compared the proposed method with the

TOF and conventional transmission methods, respectively. Section 4 demonstrates the ability of

proposed method for measuring ﬁbers with large number of modes. Finally, conclusions are drawn

in Section 5.

2. Principle for Simultaneous Measurement of MDL and DMGD

We utilize the Rayleigh backscattering amplitudes obtained with an optical reﬂectometry technique

to simultaneously measure the MDL and DMGD in FMFs. In order to der ive the equation for mode-

resolved time-dependent amplitudes of Rayleigh backscattering at the front end of the FMF, we

assumed that an optical pulse with a temporal width of T and a peak power P

is launched

at z = 0 into mode LP

. The time-dependent amplitude of Rayleigh backscattering in mode LP

received at z = 0 can be calculated by Eq. (1) [22], [23]. We use subscripts i and j (i, j = 1, 2, 3, ...,

N) to represent the mode labels (01, 11a, 11b...) of FMF, respectively.

i,j

(

)

= P

i,j

¯νT e

−2¯α¯νt

(1)

where ¯ν =

+ν

;¯α =

+α

; ν

and ν

are the attenuation coefﬁcients of modes LP

and LP

respectively; α

and α

are the attenuation coefﬁcients of modes LP

and LP

, respectively; B

i ,j

the overall backscattering capture coefﬁcient, which is quantiﬁes the ratio of the energy coupled

Vol. 11, No. 2, April 2019 7202513

剩余13页未读，继续阅读

weixin_38707192

粉丝: 3
资源: 921

使用瑞利反向散射振幅同步测量FMF中的MDL和DMGD

通过分析瑞利反向散射幅度，同时测量与模相关的损耗和少数模光纤中的模耦合

新建文件夹_去除瑞利散射_

采用经调制的正交编码的具有瑞利反向散射噪声消除功能的简单无色长距离WDM-PON

Mie_Rayleigh_Mie_Rayleigh散射_米氏散射瑞利散射建模_瑞利散射_米散射

硅基微光学谐振式陀螺瑞利背向散射噪声分析

Mie_Rayleigh_Mie_Rayleigh散射_米氏散射瑞利散射建模_瑞利散射_米散射.zip

Mie_Rayleigh_Mie_Rayleigh散射_米氏散射瑞利散射建模_瑞利散射_米散射_源码.zip

光纤拉曼放大器中双重瑞利背向散射噪声的抑制

瑞利反向散射噪声消除技术在长距离WDM-PON中的应用

磁致伸缩瑞利反向散射光谱位移：分布式磁场传感器

最新资源