The present invention provides a photon source comprising an optical waveguide and a material having at least one colour centre. The or each colour centre is arranged for photon emission and the material is grown so that the material is bonded to the optical waveguide and in use at least some of the photons emitted by the or each colour centre are guided in the optical waveguide. The present invention also provides a photon source having an optical waveguide incorporating the material which has the at least one colour centre.