Nec Corporation

Shinsuke Fujisawa

Fatih Yaman

Yoshihisa Inada

Takanori Inoue

Kohei Nakamura

Eduardo Rodriguez

Hussam Batshon

Takaaki Ogata

Yue-Kai Huang

Ezra Ip

Ryuji Aida

Takigawa Yoshinari

Aspects of the present disclosure describe systems, methods. and structures in which guided acoustic Brillouin (GAWBS) noise is measured using a homodyne measurement technique and demonstrated using a number of optical fibers, such fibers being commonly used in contemporary optical communications systems. The measurements are made with single spans and determined to be consistent with separate multi-span long-distance measurements. Additionally, a technique for preparing an optical fiber exhibiting superior GAWBS noise characteristics by reducing coherence length of the optical fiber by spinning the fiber at a high rate during the drawing process such that birefringence coherence length is reduced.

Optical fiber exhibiting low guided acoustic Brillouin scattering (GAWBS) noise and measurement thereof

Aspects of the present disclosure are directed to systems, methods, and structures providing for the accurate measurement of guided acoustic-wave Brillouin scattering in optical fiber transmission systems and facilities.

Accurate measurement for guided acoustic-wave Brillouin scattering

Aspects of the present disclosure describe estimating/measuring core-cladding concentricity error in optical fibers. In sharp contrast to the prior art, our inventive method is based on measuring a seemingly unrelated property of fibers called guided acoustic wave Brillouin scattering (GAWBS). As we shall show and describe, by analyzing this GAWBS property we advantageously determine what level of CCCE is exhibited by the optical fiber.

Estimating core-cladding concentricity error in optical fibers using guided acoustic-wave Brillouin scattering

Aspects of the present disclosure are directed to alternative repeater design(s) that advantageously improve signal-to-noise of distributed acoustic sensing (DAS) systems using coherent detection of Rayleigh backscatter in multi-span links including inline amplification that may be employed—for example—in undersea submarine systems. The repeater designs incorporate Rayleigh combine units (RCU) and Rayleigh drop units (RDU) to reduce Rayleigh backscatter loss as Rayleigh signal(s) is/are routed to a link that propagates the backscatter signal in an opposite direction relative to interrogation pulse(s).

Repeater design for distributed acoustic sensing on multispan fiber links

Aspects of the present disclosure describe systems, methods. and structures directed to an integrated 3-way branching unit switch module suitable for undersea application.

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Princeton, NJ, United States of America

Shinsuke Fujisawa