| 摘要 |
PROBLEM TO BE SOLVED: To obtain a waveguide which has a low loss, a flat upper surface of a clad layer, high dimensional accuracy and a small thickness of a substrate, and can be produced in a simple processes, by forming a core layer which is not to be irradiated with UV rays and forming upper and lower clad layers to be irradiated with UV rays on a buffer layer on a substrate. SOLUTION: The waveguide consists of a buffer layer 32 on a substrate 31, a polymer core layer 33 having an almost rectangular cross section on the buffer layer, a lower clad layer 34 formed on both sides of the core layer 33, and an upper clad layer 35 which covers the upper faces of the core layer 33 and the clad layer 34. The core layer 33 and lower clad layer 34 consist of a polymer material which decreases the refractive index by irradiation of UV rays. The core layer 33 is not irradiated with UV rays. The lower clad layer 34 consists of a polymer material which has been irradiated with UV rays and photoleached. Since the refractive index of the exposed part to LJV rays decreases, the exposed part to UV rays can be used as the clad layer. |
