Long-period fiber gratings based on blue phase liquid crystal/polymer composites

A relatively simple and cost-effective method to realise a novel long-period fibre grating (LPFG) based on blue phase liquid crystal (BPLC) composites was proposed and experimentally demonstrated by implementing photopolymerisation-induced phase separation (PIPS) through a binary photomask. The BPLC-polymer composite zones were obtained by a process of periodic ultraviolet light with phase separation of the BPLC molecules and UV-curable monomer mixture. The appearance and optical characteristics of the proposed LPFGs have been studied experimentally. Experimental results show that optimum PIPS process conditions are critical for achieving a reliable LPFG-based fibre device. Compared with the previously reported methods, this new technique for designing and making an LPFG is more cost-effective and highly flexible due to the ease in manufacturing of the grating composite structure in the all-fibre system, which can provide great potential for photonic applications.