Abstract

After detailed reviews of the exact mode field distribution of Single Mode Step-Index (SMSI) fibers and relevant definitions of Mode Field Diameter (MFD) and a careful comparison between them, a new approximate equation to calculate the mode field diameter is presented in this study. This equation is more accurate and flexible to determine MFD of Peterman I than Gaussian spot size with that of 1/e and Marcuse empirical equation, and what’s more, have a analytic solution of its inverse problem that can be used to directly calculate normalized frequency, Numerical Aperture (NA) and the cut-off wavelength. In order to evaluate the new equation, a beam propagation method that simulates the distribution of fundamental mode field is adopted. Numerical simulation results indicate that the new equation is in good agreement with the theoretical predictions. The new approximation function of MFD is a high level functional equation for the theoretical study of the characteristics of the single-mode fibers and construction of new special fibers.

Keywords:

Beam propagation method, mode field diameter, numerical aperture, single mode fiber,

References

Competing interests

The authors have no competing interests.

Open Access Policy

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Copyright

The authors have no competing interests.