The 20-year-old winger has moved to Easter Road from the English Championship side for the remainder of the 2021/22 season, with Hibs also having the option to sign him permanently in the summer.
Described by the Edinburgh club as “quick, tricky winger” who is “good with both feet”, Jasper spent the first half of the season at English League Two side Colchester United, who had hoped to extend his deal after he made 24 league and cup appearances, scoring three times.
He also bagged eight goals in 16 appearances for Fulham U23 in the Premier League 2 last season, as well as making three appearances for the Cottagers first team Fulham, with his debut coming against Manchester City in the FA Cup.
Jasper was born in England but has earned two caps for Bulgaria’s Under-21s playing against the Netherlands and Moldova.
Operating behind the striker on either side, Shaun Maloney hopes Jasper’s arrival will add a creative spark to the squad.
“Sylvester is a talented young player that possesses a lot of creativity and speed. He gives us extra options and can play on both the left and right in attacking areas,” he said.
“My staff and I are looking forward to working with him and welcoming him to the club.”
Japser’s arrival coincides with the departure of Jamie Murphy, who has joined Mansfield Town on loan.
The 32-year-old will link up with Nigel Clough’s side for the remainder of the season, with Hibs confirming the winger will leave the club when his contract expires in the summer.