كتب : Omar AbdelAziz
Bischoff, who played only once for the Bundesliga side, rejected a new deal at Weserstadion for the sake of the Gunners.
"Bremen was superb, but Arsenal is a huge opportunity for me," the French-born midfielder told Bild.
"Arsene Wenger has known me since my time at Strasbourg and believes in my quality. He trusts me to be in the first team.
"Wenger has not put me under any pressure. He said, 'Take all the time you need'."
Bischoff is the second young player to be signed by Wenger this summer, following the arrival of 19-year-old Aaron Ramsey from Cardiff.