The Cottagers announced the move on their official website, adding that they have the option to sign the 29-year-old for a further two years if they want to.
A 29-cap international for his country, Manolev started out with Pirin 1922 before a move to Litex Lovech, for whom he scored the winning goal in the 2008 Bulgarian National Cup final.
He moved to PSV in the summer of 2009 and joins AC Milan's utility man Urby Emanuelson in joining Martin Jol's Fulham on deadline day.
Twenty-six-year-old Emanuelson has also agreed to move to Craven Cottage until the end of the season.
Source: PA
Source: PA