Fasth got the deal Wednesday from the Pacific Division-leading Ducks, who have the NHL's second-best record at 12-2-1.
The Ducks signed the 30-year-old Fasth to be Jonas Hiller's backup last summer after his stellar pro career in his native Sweden.
While Hiller has been slowed by injuries this season, Fasth has been largely outstanding in his place, making nine appearances with a 1.78 goals-against average and a .933 save percentage. Fasth is just the third goalie in NHL history to win his first eight decisions.
Fasth is tied for the NHL lead with eight victories.