Abstract: 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.

Abstract: A carbon material suitable for the preparation of electrodes for electrochemical capacitors is obtained by single-stage carbonization of biopolymers with a large content of heteroatoms. Neither addition of an activating agent during carbonization nor subsequent gas phase activation is necessary. Several biopolymers which are available by extraction from seaweed are suitable precursors. Alternatively, the seaweed containing such biopolymers is carbonized directly.