Realization of periodic transmission filter based on a pair of cascaded long-period fibre gratings of different strength/wavelength position

摘要

Using high-intensity (560650 GW/cm~2) 264 nm 220 femtosecond laser pulses, we inscribed a periodic (comb) transmission filter in a photosensitive Ge/B-codoped fibre, based on a pair of long-period gratings of different strength/wavelength position. The irradiation conditions and grating parameters for the successful realization of the 2428-nm-wide transmission filter in the region 14801580 nm with the fringe period of 1.73.1 nm and the fringe bandwidth of 0.81.3 nm were established.