An FSO transceiver (4) comprising a body (6), at least one lens (9) fixed to the body in a first position (C) and means for attaching a connector (11) for an optical fiber (3) at a second position (B) at a predefined distance (Zbc) to the lens, the lens being adapted to converge rays (8) of light sent to the FSO transceiver via free space into the optical fiber. The means for attaching the connector is a temperature compensation device (10) having an expansion coefficient being higher than an expansion coefficient of the body and that the temperature compensation device is fixed to the body in a third position (A) and has a free end which allows the temperature compensation device to expand or contract according to temperature changes, and that the second position is positioned between the third position and the first position.