A component for a quantum communication system, the component comprising: an input section and a decoder section, the input section comprising n waveguides, where n is an integer of at least 2, the decoder section comprising m decoders, where m is an integer of at least 2, each decoder comprising at least one waveguide, the input section and the decoder section being provided on a single substrate such that the waveguides are continuous and integrated between the input section and the decoder section, the waveguides of the input section and the decoder section being arranged such that light pulses enter the waveguides of the decoder section via the waveguides of the input section and the m decoders operate in parallel.