Did you try a Google search? It pointed me to this mail, which indicates that you can open a file as UTF16 like this:

open FH, "<:encoding(utf16)", $filename
    or die "Couldn't open '$filename' : $!";
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I've never used anything of it, but I'm working from this line in the mail:

./perl -Ilib -we 'open(FH, "<:encoding(utf16)", "utf16");print <FH>'
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