The 19-year-old forward joins Arsenal team-mate Zac Medley at the League One outfit.
"I'm delighted to be here; it's a big step for me," said Coyle.
"I'm getting to the age where I need to play men's football and I think this is a great place for me to have my first spell.
"I'm very excited, I can't wait to get started. I'm a creative player who likes to make chances and get on the ball."