Novel in-service supervisory scheme for the amplified WDM link with modified optical time domain reflectometry

Kim, Pilhan; Yoon, Ho-Sung; Park, Namkyoo; Seo, Jeong Jin; Jeong, Ki-Tae; Ryoo, Ki-Won; Lee, Kyu-Haeng; Blow, Justin; Fleming, Simon

doi:10.1016/s1068-5200(02)00001-9

Cited by 2 publications

(2 citation statements)

References 7 publications

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“…In the absence of electrical regeneration, which can provide distributed feedback on the bit error rate (BER), optical techniques are used. The most famous optical line monitoring technique, which was first developed in the late 80s, uses coherent optical time domain reflectometry to monitor optically amplified submarine cable systems [1][2][3][4]. The main disadvantage of this method is the cost, largely related to the use of optical coherent detection.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effect of an increased supervisory signal power in a high‐loss loopback monitoring system

Nahas

Blow

2014

IET Communications

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We present experimental results for the effect of an increased supervisory signal power in a high-loss loopback supervisory system in an optically amplified WDM transmission line. The paper focuses on the investigation of increasing the input power for the supervisory signal and the effect on the copropagating WDM data signals using different channel spacing. This investigation is useful for determining the power limitation of the supervisory signal if extra power is needed to improve the monitoring. The paper also shows the effect of spacing on the quality of the supervisory signal itself due to interaction with adjacent data signals.

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Section: Introductionmentioning

confidence: 99%

Investigation of the effect of an increased supervisory signal power in a high‐loss loopback monitoring system

Nahas

Blow

2014

IET Communications

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“…On the other hand, the main requirement of the line monitoring system is that it should have a much lower cost than the transmission link itself; otherwise it is not a cost-effective solution. To meet such a requirement, several optical line monitoring techniques have been developed, where the most famous technique was based on coherent optical time domain reflectometry (COTDR) [2], [3], [4], [5], [6], [7] and [8]. The main advantage of COTDR is that it can define the fault at any part of the system rather than just the output from the repeaters as in other techniques.…”

Section: Introductionmentioning

confidence: 99%

Monitoring long distance WDM communication lines using a high-loss loopback supervisory system

Nahas

Blow

2012

Optics Communications

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In this paper, we present experimental results for monitoring long distance WDM communication links using a line monitoring system suitable for legacy optically amplified long-haul undersea systems. This monitoring system is based on setting up a simple, passive, low cost high-loss optical loopback circuit at each repeater that provides a connection between the existing anti-directional undersea fibres, and can be used to define fault location. Fault location is achieved by transmitting a short pulse supervisory signal along with the WDM data signals where a portion of the overall signal is attenuated and returned to the transmit terminal by the loopback circuit. A special receiver is used at the terminal to extract the weakly returned supervisory signal where each supervisory signal is received at different times corresponding to different optical repeaters. Therefore, the degradation in any repeater appears on its corresponding supervisory signal level. We use a recirculating loop to simulate a 4600 km fibre link, on which a high-loss loopback supervisory system is implemented. Successful monitoring is accomplished through the production of an appropriate supervisory signal at the terminal that is detected and identified in a satisfactory time period after passing through up to 45 dB attenuation in the loopback circuit. AcknowledgmentsThe authors are thankful to all those who contributed to this work, namely:

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Novel in-service supervisory scheme for the amplified WDM link with modified optical time domain reflectometry

Cited by 2 publications

References 7 publications

Investigation of the effect of an increased supervisory signal power in a high‐loss loopback monitoring system

Investigation of the effect of an increased supervisory signal power in a high‐loss loopback monitoring system

Monitoring long distance WDM communication lines using a high-loss loopback supervisory system

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