Beat Power Calculation for Arbitrarily Polarized Lightwaves by Using the Inner Product of Stokes Vectors

Youichi FUKADA  Shigeru KUWANO  Katsushi IWASHITA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E87-B   No.6   pp.1451-1462
Publication Date: 2004/06/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Fiber-Optic Transmission
Keyword: 
beat noise,  polarization,  Stokes vector,  inner product,  polarization-dependent loss,  polarization scramble,  

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Summary: 
Because of the polarization dependencies of optical fiber transmission equipment, the polarization state of lightwaves inherently varies at the optical receiver input. Therefore the receiver output, especially the beat component, is very dependent on the polarization state. We derive a simple relation showing that the beat power of the lightwaves is proportional to the inner product of their Stokes vectors. Using this relation, we can systematically calculate the beat power. This calculation method can be applied to lightwaves of arbitrary polarization, such as a polarization-scrambled signal or partially polarized amplified spontaneous emission (ASE) in long-haul IM/DD systems, as well as to the signal and local oscillator lightwaves of coherent systems.