A method is provided to perform an optimized setting of an optical detection device, with the detection device comprising a first and a second waveguide, each having an end face adapted for emitting and receiving light and facing each other in a distance d, and an envelope which at least partially envelopes said distance d and which is adapted for at least partially guiding light between the end sides. The method comprises measuring of a transmission characteristic between the waveguides, which transmission characteristic shows at least one of a minimum and a plateau and which is dependent on the distance d, and setting of the distance d to a working point on the distance d in the minimum or plateau, wherein the variation of the transmission around the working point is low, accordingly the derivation of the measured transmission characteristic is low.