| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical filter which is excellent in temp. stability and allows the fine adjustment of a band center wavelength. SOLUTION: Optical gratings 2 which impart the wavelength standard of filter characteristics are constituted in an optical waveguide 1 consisting of a core 3 and a clad layer 4 of this filter. In such a case, the clad layer of at least part of the optical gratings 2 is formed thin and an optical medium 6 having the temp. coefft. of the code reverse from the code of the refractive index of the core 3 and the clad layer 4 is deposited on this thin region 5. |
