| 摘要 |
PROBLEM TO BE SOLVED: To improve the dependence of the gratings which are manufactured in a quartz optical waveguide by utilizing the refractive index change by photoinduction, on temp. SOLUTION: A core and a clad are formed by a CVD method mainly using the alkoxide of Si, for example, TEOS(tetraethyl orthosilicate), as a raw material. The core is then irradiated with an excimer laser via a phase mask, by which the gratings 13 are formed on the core. A thin-film heater (heater electrode 14a, input/output electrodes 14b, current leads 14c) of chromium or platinum is formed on the optical waveguide. Further, the fine adjustment of the Bragg central wavelength of the gratings is executed by the current control to the thin-film heater, by which the optical filter corresponding to the light signal subjected to high-density wavelength multiplexing is manufactured. |
