| 摘要 |
PURPOSE:To allow the formation of the single-mode optical wave guide while setting the structural parameter of the optical wave guide in such a manner that the parameter coincides with the structural parameter of the input/output wave guide by providing an additive layer on an upper clad layer so as to be adjacent one side of the projecting part of the upper clad layer and setting the refractive index of this additive layer at the refractive index lower than the refractive index of the upper clad layer and higher than the refractive index of air. CONSTITUTION:This optical wave guide has the constitution which is successively provided with a lower clad layer 36, an optical wave guide layer 38, and the upper clad layer 40 having a striped projecting part 40a and is further provided with the additive layer 42 on the upper clad layer 40 adjacent to one side of the projecting part 40a. The refractive index of the additive layer 42 is set at the refractive index lower than the refractive index of the upper clad layer 40 and higher than the refractive index of air. The structural parameter of the optical wave guide is made coincident with the structural parameter of the input/output wave guide in this way, by which the coupling loss is decreased and the formation process is simplified; in addition, the formation of the single mode optical wave guide of this embodiment is enabled by controlling the layer thickness of the additive layer. |
