The left-back, who turned 20 last month, will stay at Griffin Park until May 6.
The deal could be extended further if the Bees are involved in the League One play-off final. They are currently in fourth spot, five points adrift of the automatic promotion places and five clear of Tranmere in seventh.
Bidwell also spent six months with the Bees last season and has made 42 appearances so far this term.
- Sports & Recreation