Measurement of the Nonlinear Ratio (n2/Aeff) in Optical Fibers Using Self-Phase Modulation Effect

  • Ahmad K. Atieh
  • Piotr Myslinski
  • Jacek Chrostowski
  • Peter Galko

Abstract

Future optical communication systems will have to provide ultra-high speed transmission rates over long distances. An important limitation for such systems is imposed by the fiber nonlinearity typically described by the coefficient:
$$\gamma = \frac{{2\pi {n_2}}}{{\lambda {A_{eff}}}}$$
(1)
where n2is the nonlinear refractive index of the fiber, A eff is the fiber effective core area, and X is wavelength of the propagating signal. To design systems for such applications, it is necessary to determine the ratio n 2/A eff with high accuracy. The nonlinear properties of the fibers have been determined recently by measuring the self-phase modulation (SPM) effect using propagation of a short pulse at 1.3 μn through the tested fibers [1]. A different technique was employed in reference [2], where cross-phase modulation effect between a low power probe signal at 1550 nm and a high power pump signal at 1540 nm was used to find the nonlinear characteristics of the fiber. The ratio n 2/A eff was also measured based on the generation of beating frequency components through four-wave mixing (4WM) of two DFB laser diodes operating around 1555 nm [3]. In this scheme, two cw laser beams with frequencies v1 and v2 are launched into the fiber under test. The two beams with different power levels generate new beat frequencies (2V1-V2) and (2 V2-2V1) through 4WM process. All these schemes measure the nonlinear ratio of the fiber and an independent measurement of the effective core area enables the estimation of the nonlinear refractive index.

Keywords

Microwave Attenuation Soliton Sine Coupler 

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Copyright information

© Springer Science+Business Media New York 1997

Authors and Affiliations

  • Ahmad K. Atieh
    • 1
  • Piotr Myslinski
    • 2
  • Jacek Chrostowski
    • 2
  • Peter Galko
    • 1
  1. 1.Electrical Engineering DepartmentUniversity of OttawaOttawaCanada
  2. 2.National Research CouncilInstitute for National Measurements StandardsOttawaCanada

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