The midfielder has joined Fulham in a permanent deal this weekend.
"From Hale End to the Emirates and all the memories on our journey," posted Saka. "It’s been an absolute pleasure. Go and shine bro!"
Gunners boss Mikel Arteta has also stated: “Emile’s commitment, attitude and energy every day was first class, always stepping up when the team needed him.
“He came into the first team and was instrumental during a difficult moment for us. He created an important impression, with his strong performances making our supporters proud.
“I’m sad that Emile is leaving us, but excited for him to take this new opportunity at this stage of his career, when he needs to be starting matches and playing regularly.
“Emile is loved by everyone at the club and leaves us with our gratitude, absolute respect and best wishes. We all wish Emile and his family well at Fulham.”