Perl 6 has many compiler and interpreter and none is "the official Perl 6". Larry Wall said: everything that passes the test suite, is Perl 6. But all those here mentioned currently understand only a subset.
Rakudo is currently the most feature rich and the most actively developed implementation. It runs on Parrot, a virtual machine for any dynamic language.
Pugs was the leading implementation from 2005 until about 2007. It is written in Haskell, a language for functional programming.
STD.pm is "the" canonical Perl 6 language definition, written in Perl 6 itself. It consists mainly of a large grammar. Unfortunately there is no implementation that can execute