The invention relates to a method and device for controlling a physical parameter of an optical signal. According to the invention, a portion of the initial optical signal (SE) having passed through an optical waveguide from the input (24.1) to the output (24.2) thereof, is returned into said optical waveguide (24) using a sequential circulator (25) and an optical amplifier (28), in order to at least partially form the optical control signal (SE2), which counter-propagates relative to said initial optical signal (SE), so as to stabilize, or at the very least control, the physical parameter of said initial optical signal when the latter exits said optical waveguide (24) via the output (24.2) thereof.