Birefringent azopolymer long period fiber gratings induced by 532nm polarized laser

Fabrication of Polymer Optical Fibre (POF) Gratings

“…Therefore, functional dopants, such as fluorescein, trans -4-stilbenemethanol (TSB), benzildimethylketal (BDK), 9-vinylanthracene (VA), etc. have been introduced into POF for the enhancement of the photosensitivity, as listed in Table S1 [22,64,65,66,67,68,69]. The incorporation can be either through the simple doping with small molecules [22,64,65], or through the co-polymerization with photosensitive monomers [66,67,69].…”

“…The photosensitivity of two dopants, azobenzene [67,69,71,72,73,74] and Photosol 7-049 [56] is found to be reversible. The former can be photoaligned under linearly polarized light and erased by circularly polarized light, which will write/erase the photoinduced birefringence for forming/erasing of fibre gratings.…”

“…The bulk polymerization often gives more flexibility for the modification of the material properties through doping to improve the photosensitivity [22,64,65,66,67,68,69] as well as other functionalities. MM graded-index (GI) perfluorinated POF (CYTOP) is manufactured by Chromis Fiberoptics, Inc. (Warren, NJ, USA) through extrusion [48,92].…”

“…Photosensitive POFs have mainly been reported by several research groups, listed in Table 2 [22,64,65,66,67,68,75,77,97]. These POFs have varying specifications (loss concentricity, diameter, photosensitivity, drawing induced anisotropy) [98].…”

LPG in perfluorinated GI-POF for concentration measurement in liquids

“…The authors reported a diffraction efficiency of 1.6% and a modulation index of photoinduced 3x10 -4 and concluded inability to written grating directly in the core. On the other hand, the LPGs in POF commercially available are lacking in most studies fiber Bragg grating (FBG) in the POF have been made based cores poly-methyl-methacrylate (PMMA) doped with other monomers or colorants prepared by the same authors [10,11]. This paper first presents the fabrication of LPGs in PF-GI-POF using UV pulsed laser to wavelength of 355 nm.…”