The invention provides a waveguide comprising a channel 12 on an optical substrate 11, the refractive index of the channel being higher than that of the substrate. The waveguide includes at least one guide layer 13 arranged on the channel, the index of said guide layer being higher than that of the substrate. In addition, the channel 12 is integrated in the substrate 11. advantageously, the waveguide further includes a covering layer 14 deposited on the guide layer 13, the index of said covering layer being lower than that of the guide layer and lower than that of the channel. The invention also provides a method of fabricating the waveguide.