Abstract: The active base comprises a body (10) having a cylindrical hole (12) in which an optical module (13) is inserted, said module being constituted by a socket (22) about an axis XX', a hollow cylindrical support (26) having a bottom including a hole, a diode (25) mounted in the support, with the diode package having a flange (251) that bears against the bottom of the support. The hole through the support has a diameter which is greater than the diameter of the package to enable the diode to be positioned on the axis XX'. A spring ring (28) is inserted in the support after the diode has been positioned. When the diode is suitable for emitting or receiving a convergent light beam, the socket includes a centering ring (24) disposed ahead of the diode and containing a rod lens (23) in the middle thereof.