Boss Kevin Dillon told the club website: "He's hungry to succeed. This is his opportunity to stake a claim for something more permanent.
"With John Grant joining Oxford it was important that we signed Omer to provide good competition."
The Edmonton-born striker started his career as a trainee at Arsenal, making one appearance in the League Cup, before spells at West Ham United and Barnet.
He spent five years playing for Turkish side Denizlispor.
Source: BBC Sport
Source: BBC Sport