| 摘要 |
Method for compensation of group delay dispersion in an add-drop filter comprising a passive main filter (1) comprising a Mach-Zender interferometer with two identical Bragg gratings (3,4) placed in the respective arms of the Mac-Zender interferometer. The invention is characterized in, that after the main filter (1), in the travelling direction of introduced light, group delay dispersion from the main filter is compensated for by a compensator (18;19) in the form of a reflector for light leaving the main filter, where the bandwidth of reflection of the compensator is larger than that of the main filter and where the reflection spectrum of the compensator (18,19) is substantially 100% for the wavelength range defined by the main filter (1). |
