We demonstrate a long period grating (LPG) inscription in microstructured polymer optical fibers (mPOFs) using a single 248 nm UV laser pulse of 15 ns duration for every inscription point using a point by point technique with total length of 25 mm. The fabrication time indicates shortening for a single coupling point (15 ns against 42 s reported in literature). A grating with 20 dB transmission dip has been fabrication by using two UV pulses for each coupling point. The device has been fabricated in mPOF with a core that has been doped with benzyl dimethyl ketal (BDK) for photosensitivity increase. The strain and temperature responses of the fabricated gratings under different conditions have been characterized in order to assess the viability for sensing applications. Better performance was achieved with suitable post annealing process of the gratings.
In this contribution we report on the fabrication of novel bandpass transmission filters based on PS-FBGs in microstructured polymer fibers at telecom wavelengths. The phase mask technique is employed to fabricate several superimposed gratings with slight different periods in order to form Moiré structures with a single or various π phase shifts along the device. Simulations and experimental results are included in order to demonstrate very narrowband transmission filters. Experimental characterization under strain and temperature variations is provided in a non-annealed fiber and time stability of the fabricated devices has been also measured under different pre-strain conditions.