Observation of polarization modulation at the output of a submarine link, extracted from a standard coherent telecom receiver, can be used to monitor geophysical events such as sea waves and earthquakes occurring along the cable. We analyze the effect of birefringence perturbations on the polarization at the output of a long-haul submarine transmission system, and provide analytical expressions instrumental to understanding the dependence of the observed polarization modulation on the amplitude and spatial extension of the observed events. By symmetry considerations, we show that in standard single mode fibers with random polarization coupling, if polarization fluctuations are caused by strain or pressure, the relative birefringence fluctuations are equal to the relative fluctuations of the polarization averaged phase. We finally show that pressure induced strain is a plausible explanation of the origin of polarization modulations observed in a long submarine link. The presented analysis paves the way for the transformation of transoceanic fiber optic links during operation into powerful sensing tools for otherwise inaccessible geophysical events occurring in the deep ocean.

Polarization sensing using submarine optical cables

Mecozzi, Antonio;
2021

Abstract

Observation of polarization modulation at the output of a submarine link, extracted from a standard coherent telecom receiver, can be used to monitor geophysical events such as sea waves and earthquakes occurring along the cable. We analyze the effect of birefringence perturbations on the polarization at the output of a long-haul submarine transmission system, and provide analytical expressions instrumental to understanding the dependence of the observed polarization modulation on the amplitude and spatial extension of the observed events. By symmetry considerations, we show that in standard single mode fibers with random polarization coupling, if polarization fluctuations are caused by strain or pressure, the relative birefringence fluctuations are equal to the relative fluctuations of the polarization averaged phase. We finally show that pressure induced strain is a plausible explanation of the origin of polarization modulations observed in a long submarine link. The presented analysis paves the way for the transformation of transoceanic fiber optic links during operation into powerful sensing tools for otherwise inaccessible geophysical events occurring in the deep ocean.
File in questo prodotto:
File Dimensione Formato  
optica-8-6-788.pdf

accesso aperto

Tipologia: Documento in Versione Editoriale
Licenza: Dominio pubblico
Dimensione 10.83 MB
Formato Adobe PDF
10.83 MB Adobe PDF Visualizza/Apri
optica-8-6-788-compresso.pdf

accesso aperto

Descrizione: File in versione editoriale compresso
Tipologia: Documento in Versione Editoriale
Licenza: Dominio pubblico
Dimensione 777.31 kB
Formato Adobe PDF
777.31 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11697/167112
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 6
social impact