The variation of the optical properties of He + implanted planar optical waveguides formed by multiple implantations into LiNbO 3 has been investigated. The results show that by sharing the total dose per sample equally between two implants of different energy, the number of modes supported by the waveguide may be increased and the fundamental mode attenuation decreased. Graded refractive index depth profiles can be produced using 66% of the total sample dose in the deeper implant and results in a reduction of the waveguide attenuation to 2.4 dB cm −1 and 1.5 dB cm −1 for the TM and TE modes, respectively.