| 摘要 |
PURPOSE:To make stable polarization and sepn. by forming a total reflective part by using the end face or etching groove of a substrate and conducting ordinary ray and extraordinary ray to respective separate waveguides. CONSTITUTION:There is the total reflective surface 6 of which the end part is diagonally cut off on one face of an LiNbO3 substrate 5 contg. an optical axis on the surface. Light makes different reflections by double refractions if the light is projected onto such surface through an incident waveguide 7 parallel with the optical axis. The reflected light is then separated to the TM mode light 8 which is the ordinary rays and the TE mode light 9 which is the extraordinary ray. This waveguide separates the light by utilizing such sepn. and forming the pattern of the waveguides to the above-mentioned position. The conditions under which the total reflection arises require that the cosine of an incident angle theta be larger than the inverse number of the refractive index (n) of LiNbO3. The total reflection conditions can be made no only at the end face of the substrate 5 but also by etching on the substrate 5. More specifically, the substrate is linearly dry-etched to the angle satisfying the above-mentioned total reflection conditions by utilizing a photoetching technique to form a groove 10 having the total reflection surface and an indicent waveguide 7 and the waveguides in which the TM mode light 8 and the TE mode light 9 propagate are patterned in the form of intersecting diagonally therewith. |
