The 20-year-old, whose contract will keep him at the club until 2014, has scored five tries in five appearances so far in this year's campaign.
"I'm really happy to get another few years at the Broncos," Dixon told the club's official website. "Everything has gone really fast, it's seems like just a few hours since I was making my debut against St Helens and playing the majority of the season. To be where I am now is just a massive achievement.
Head coach Tony Rea added: "People can see everything he does on the field. He contributes well and the really pleasing thing is he contributes off the field.
"He's a really important person and he's a pleasure to have around the place. He represents the club and everything we're about by the way he represents himself."
Dixon was the club's leading try-scorer in 2012 with 16.