Submarine optical fiber cable: development and laying results

Kojima, N.; Yabuta, Tetsuro; Negishi, Y.; Iwabuchi, Kazuo; Kawata, O.; Yamashita, Kazuya; Miyajima, Y.; Yoshizawa, Noriko

doi:10.1364/ao.21.000815

Cited by 27 publications

(3 citation statements)

References 1 publication

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“…The cable's sensitivity to pressure is highly dependent on the cable design. For an optical submarine cable assembly, E ∼ 5 − 50 GPa and ν ∼ 0.2 − 0.25 (Kojima et al, 1982;Tatekura et al, 1982). The lower values of E and larger values of ν correspond to less armored cables.…”

Section: Poisson's Effectmentioning

confidence: 99%

Towards tsunami early-warning with Distributed Acoustic Sensing: Expected seafloor strains induced by tsunamis

Becerril,

Sladen,

Ampuero

et al. 2024

Preprint

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Tsunami wave observations far from the coast remain challenging due to the logistics and cost of deploying and operating offshore instrumentation on a long-term basis with sufficient spatial coverage and density. Distributed Acoustic Sensing (DAS) on submarine fiber optic cables now enables real-time seafloor strain observations over distances exceeding 100 km at a relatively low cost. Here, we evaluate the potential contribution of DAS to tsunami warning by assessing theoretically the sensitivity required by a DAS instrument to record tsunami waves. Our analysis includes signals due to two effects induced by the hydrostatic pressure perturbations arising from tsunami waves: the Poisson’s effect of the submarine cable and the compliance effect of the seafloor. It also includes the effect of seafloor shear stresses and temperature transients induced by the horizontal fluid flow associated with tsunami waves. The analysis is supported by fully coupled 3-D physics-based simulations of earthquake rupture, seismo-acoustic waves and tsunami wave propagation. The strains from seismo-acoustic waves and static deformation near the earthquake source are orders of magnitude larger than the tsunami strain signal. We illustrate a data processing procedure to discern the tsunami signal. With enhanced low-frequency sensitivity on DAS interrogators (strain sensitivity ≈ 2×10 at mHz frequencies), we find that, on seafloor cables located above or near the earthquake source area, tsunamis are expected to be observable with a sufficient signal-to-noise ratio within a few minutes of the earthquake onset. These encouraging results pave the way towards faster tsunami warning enabled by seafloor DAS.

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Section: Poisson's Effectmentioning

confidence: 99%

Towards tsunami early-warning with Distributed Acoustic Sensing: Expected seafloor strains induced by tsunamis

Becerril,

Sladen,

Ampuero

et al. 2024

Preprint

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“…There are some additional elements in general optical glass, many of which are impurities. And most of them have electron states with low excitation energy (Kojima et al 1982). Meanwhile, there are also some metal ions whose electron states are more easily excited than the intrinsic properties of glass.…”

Section: Basic Propertymentioning

confidence: 99%

Fiber-Optic Cable

Yan¹,

Ying²,

Yang³

et al. 2019

Encyclopedia of Ocean Engineering

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It is with the purpose of meeting the performance specifications of optics, machinery, and the environment that optical fiber cables are made. Communication cable assemblies with one or more optical fibers in the cladding sheath of optical cables are made used as the transmission medium and can be used individually or in groups. In the structure of optical cables, a certain amount of fibers is used to form the cable core in a certain way, some of which are covered with outer sheath. Generally speaking, optical fiber cables are communication lines used to transmit optical signals (Hogari et al. 2008). Although there is certain tensile strength of optical fibers, the strength is not strong enough to withstand the practical situations of bending, twisting, and side pressure. Thus, the traditional cable which contains technology should be used, such as fitting, overlaying plastic, metal tape armoring, and so on, just like the copper cables of communication. And then, in order to make a variety of optical cables which can be used in different environments, the strength component materials are placed in the cable core, so that it can meet the laying conditions required by the projects; achieve the mechanical performances of resistance to tension, impact, bending, distortion, and so on in practical situations; and ensure the original great transmission performance of the unchanged optical fibers (Shimizu 2008). Scientific Fundamentals Basic Structure Optical cable is mainly composed of optical fiber (glass which is as thin as hair), plastic protective sheath, and plastic outer layer. It can be divided into fiber core, reinforcing steel wire, filler, and sheath. In addition, there are waterproof layer, buffer layer, insulation metal wires, and other components according to the demand. To some extent, the performance of the optical fibers has an impact on the performance of optical cables. Fiber

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“…In the last decades, the underwater wireless communication has attracted a remarkable attention as it is capable of providing a higher flexibility and cost-effectiveness than submarine optical fiber communication which can only be used in the data transmission between the static objects in the water [1][2][3]. Up to now, the underwater wireless communication has been widely used in the data transmission between various underwater vehicles, sensors and observatories [3,4].…”

Section: Introductionmentioning

confidence: 99%