Examples of wavelength division multiplexers using multidielectric filters, gratings or both of them, published by different authors, are given. The filter devices are well adapted to the multiplexing of a small number of channels with large distances between wavelengths. It is proposed to apply to these devices the principle of multiplexing with 'shared optical functions technology' which enables the cost-price of the multiplexing and coupling to be reduced for the most videocom optical network.