Waveguide amplifier and waveguide amplifier fabrication method

The present invention concerns a waveguide amplifier comprising: - at least one embedding cladding material or layer, and - at least one rare-earth ion implanted silicon nitride material or layer embedded in the at least one embedding cladding material or layer, the at least one rare-earth ion implanted silicon nitride material or layer defining a waveguide core enclosed by the at least one embedding cladding material or layer.