Wickens moves to the Imps for an undisclosed fee.
The 22-year-old former England Under-18 international has signed a four-year contract.
Lincoln boss Michael Skubala told the club website:, external “George has all the attributes we look for in a goalkeeper and impressed us with his mentality and maturity in the recruitment and interview process.
"George has shown his character with his decision to leave Fulham in order to play regularly and forge his career as a number one goalkeeper.”
Director of football Jez George said: “To have executed this signing in such a timely manner hopefully evidences our recruitment process and planning.
"It also demonstrates how our model works by us investing a proportion of the transfer fee received for Lukas into such a talented young goalkeeper with huge potential and future asset value."