# Tikzpicture for BER graph

I have very simple question but It probably does not have easy answer. I am using the following BER diagram but I will welcome another version, improvements or suggestion for better graph.

Thank you very much for each suggestion or different type for BER.

My code is here:

\documentclass{article}
\usepackage{pgfplots}

\pagestyle{empty}

\begin{document}

\begin{tikzpicture}
\begin{axis}[height=7cm,width=10cm,xlabel=EDFA output power (dBm),ylabel=Q factor (---),legend pos=south west, grid=major]

(   18  ,   13  )
(   19  ,   12.9    )
(   20  ,   12.3    )
(   21  ,   11.9    )
(   22  ,   11.7    )
(   23  ,   11.4    )
(   24  ,   11.1    )
(   25  ,   11  )
(   26  ,   11  )
(   27  ,   10.9    )
};

(   18  ,   13  )
(   19  ,   12.6    )
(   20  ,   12.2    )
(   21  ,   12.2    )
(   22  ,   11.7    )
(   23  ,   11.1    )
(   24  ,   11  )
(   25  ,   10.8    )
(   26  ,   11  )
(   27  ,   10.9    )
};

(   18  ,   13.1    )
(   19  ,   13.1    )
(   20  ,   13  )
(   21  ,   12.9    )
(   22  ,   12.4    )
(   23  ,   11.7    )
(   24  ,   11.6    )
(   25  ,   10.8    )
(   26  ,   10.7    )
(   27  ,   10.3    )
};