OTDR performance enhancement using a quaternary FSK modulated probe and coherent detection

Sumida, M.

doi:10.1109/68.372764

Cited by 18 publications

(13 citation statements)

References 6 publications

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“…Afterwards, we can simultaneously detect and process multiple IF signals generated in the coherent detection process between the Rayleigh signals of the multi-frequency probe backscattered in the fiber under test (FUT) and the original single-frequency LO. This process speeds up measurement efficiency, compared with conventional singlefrequency probe based C-OTDR [4,5] . The schematic diagram of the multi-frequency probe (MFP) based C-OTDR is shown in Fig.…”

Section: Coherent Optical Time Domain Reflectometry (C-otdr)mentioning

confidence: 99%

“…Therefore, compared with the conventional single-frequency probe based C-OTDR, according to the experimental results shown in Fig. 7, SBS threshold improvement by PM in the MFP C-OTDR cannot enhance the maximum dynamic range; in addition, the dynamic range is improved mainly by enhancing measurement efficiency [4,5] . In conclusion, the non linear effects that limit the performance of the MFP C-OTDR are investigated and discussed.…”

Section: Coherent Optical Time Domain Reflectometry (C-otdr)mentioning

confidence: 99%

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Performance limit of a multi-frequency probe based coherent optical time domain reflectometry caused by nonlinear effects

Lv¹,

Song²,

Zhu³

et al. 2012

中国光学快报

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The nonlinear effects that limit the performance of the multi-frequency probe (MFP) based coherent optical time domain reflectometry (C-OTDR) are investigated. Based on theoretical analysis and experimental results, compared with conventional C-OTDR, when the probe pulse has power gradient within the pulse width, self-phase modulation (SPM) and cross-phase modulation (XPM) are strengthened in the new C-OTDR scheme. The generation of four-wave mixing (FWM) is dependent on SPM and XPM, and with modulation frequency of phase modulator higher than 40 MHz, the stimulated Brillouin scattering (SBS) threshold can be enhanced by more than 5 dB, which benefits the maximum dynamic range of the MFP C-OTDR.

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Section: Coherent Optical Time Domain Reflectometry (C-otdr)mentioning

confidence: 99%

Section: Coherent Optical Time Domain Reflectometry (C-otdr)mentioning

confidence: 99%

Performance limit of a multi-frequency probe based coherent optical time domain reflectometry caused by nonlinear effects

Lv¹,

Song²,

Zhu³

et al. 2012

中国光学快报

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“…There are three main methods that can fill this goal: the first is to increase the probe pulse power to correspondingly improve the backscattered signal power, then the second is to use high performance photo detector with low noise level, and the third is to increase measurement and average times to reduce noise level, which is essential in OTDR system for it contributes a 27dB DR enhancement by measurement of 2 18 times [4]. Therefore, it is a potential way to fast increase measurement times even if the hardware of the OTDR system such as laser and photo detector is perfect [8].However, conventional OTDR only sends one probe pulse in a pulse period which is usually a little larger than the round-trip time of the probe pulse propagating in fibre under test (FUT), so, to increase measurement number means to extend measurement time and thus most of the time in the fixed pulse period is wasted. To solve this problem, multiplexing methods, which are widely used in communication technology to increase the data transmission capacity, are employed to enhance the measurement efficiency of OTDR system [9][10][11].…”

Section: Introductionmentioning

confidence: 97%

A new OTDR based on probe frequency multiplexing

Liu

Liang

et al. 2013

SPIE Proceedings

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Two signal multiplexing methods are proposed and experimentally demonstrated in optical time domain reflectometry (OTDR) for fault location of optical fiber transmission line to obtain high measurement efficiency. Probe signal multiplexing is individually obtained by phase modulation for generation of multi-frequency and time sequential frequency probe pulses. The backscattered Rayleigh light of the multiplexing probe signals is transferred to corresponding heterodyne intermediate frequency (IF) through heterodyning with the single frequency local oscillator (LO). Then the IFs are simultaneously acquired by use of a data acquisition card (DAQ) with sampling rate of 100Msps, and the obtained data are processed by digital band pass filtering (BPF), digital down conversion (DDC) and digital low pass filtering (BPF) procedure. For each probe frequency of the detected signals, the extraction of the time domain reflecting signal power is performed by parallel computing method. For a comprehensive performance comparison with conventional coherent OTDR on the probe frequency multiplexing methods, the potential for enhancement of dynamic range, spatial resolution and measurement time are analyzed and discussed. Experimental results show that by use of the probe frequency multiplexing method, the measurement efficiency of coherent OTDR can be enhanced by nearly 40 times.

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“…The first relies on the use of pilot signals, which are known signals inserted to travel along the same paths as data signals but are distinguishable from data signals. As an alternative, we can use an optical time domain reflectrometer (OTDR) to detect the echo of pilot signals at the transmitter [9]. The second approach is based on observing the statistical parameters such as optical signal average power, optical signal frequency spectrum, and the BER of a lightpath [10]- [12].…”

Section: Existing Supervisory Methodsmentioning

confidence: 99%

“…We can extend the result from theorem 1 to the case with , problem (5) becomes minimize subject to (9) The Lagrange multiplier method gives the same condition as in (7), namely , . We have from Lemma 1 that under Assumption 1 there exists at most one positive solution to in .…”

Section: A Worst-case Scenario For Andmentioning

confidence: 99%

Guaranteeing the BER in transparent optical networks using OOK signaling

Saengudomlert

Médard

2002

IEEE J. Select. Areas Commun.

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Abstract-A network consisting of transparent optical nodes (TONs) can provide high speed end-to-end communication paths with very low bit-error rates (BERs). However, owing to component crosstalk and other degradations at TONs, the BER of a particular communication path traversing several TONs can be degraded by a few orders of magnitude even in the absence of component failure. Monitoring the quality-of-service (QoS) of a communication path has typically relied on sporadic BER testing and operation monitoring by the nodes using probe signals. Intermittent BER testing cannot provide continuous monitoring of the network QoS. On the other hand, the use of probe signals is not sensitive enough to detect the BER degradation. This work investigates a novel approach of monitoring service degradation at individual nodes using a wrap-around device which taps and compares signals from the input and the output at each TON along the lightpath. We propose a modification using hard limiters at TON inputs and derive the BER value that this modified method can guarantee in the presence of signal degradation due to coherent crosstalk at TONs.

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OTDR performance enhancement using a quaternary FSK modulated probe and coherent detection

Cited by 18 publications

References 6 publications

Performance limit of a multi-frequency probe based coherent optical time domain reflectometry caused by nonlinear effects

Performance limit of a multi-frequency probe based coherent optical time domain reflectometry caused by nonlinear effects

A new OTDR based on probe frequency multiplexing

Guaranteeing the BER in transparent optical networks using OOK signaling

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