| 摘要 |
<p>A lightwave filter which allows optical signals of a plurality of wavelength channels to be extracted even in the case of high-density multiplexing. It is provided with two rows of optical fiber gratings (16a, 16b), each with two fixed gratings (12), wherein the reflection wavelength is fixed, and two variable grating (14), wherein the reflection wavelength can be shifted, connected rectilinearly to each other. It also has an optical circulator (18) which guides optical signals of wavelength channels reflected by the first row of gratings (16a) to the second row of gratings (16b). Of the variable gratings (14), the reflection wavelengths of those having basic reflection wavelengths which correspond to wavelength channels not selected from among the input optical signals are shifted to wavelengths other than the basic reflection wavelengths of the other variable gratings of the same row. This allows optical signals of selected wavelengths to be selected, while those of unselected wavelengths pass through. <IMAGE></p> |
