| 摘要 |
PURPOSE:To polish the waveguide end surface without increasing the waveguide loss of the waveguide by forming a protection film on the surface of a substrate where the waveguide is formed, then, polishing the substrate end surface that the waveguide faces. CONSTITUTION:The buried type waveguide 2 is formed on the surface of the LiNbO3 substrate 1 first. Then the protection film 3 is made of SiO2 on the surface by a plasma method to specific thickness. Two substrates which are processed as mentioned above are stuck in facing their films 3 to each other, clamped in this state by a polishing jig 5 from above and below, and held. At this time, the substrate end surfaced that the end surface of the waveguide 2 faces is held slightly projecting from the front surface of the jig 5. In such a state, the substrate end surface is polished by a grindstone. The substrates are taken out of the jig 5 after the polishing, the formed SiO2 films are utilized as buffer layers as they are, and an Au electrode 6 is formed on the part where the waveguide 2 is formed. This method prevents the waveguide surface from flawing by the protection films during the polishing of the waveguide end surface. |
