Abstract: A polymeric wave guide comprises a first layer of a polymer having a first refractive index, and the first layer contains retaining features or groves which will accept a second polymer. A second polymer is curable and is used to fill the retaining features has a refractive index which is greater than the polymer used to produce the first layer. The retaining features of the first polymeric layer are filled with the second polymer by pressing the second polymer into the retaining features by applying an advancing force to a flexible dispensing layer; this results in filling the retaining features and producing a thin over layer having a thickness of less than 1.5 .mu.m of the second polymer over the surface of the first layer. The method further comprises a step in which the second polymer is cured.