Spectral characterization of helicoidal long-period fiber gratings in photonic crystal fibers

We report a new helicoidal long-period grating by twisting a photonic crystal fiber under CO2 laser irradiation and experimentally investigated its novel transmission characteristics. The fabricated helicoidal PCF-LPG has a relatively short length of similar to 1.4 cm with a low polarization dependent loss less than 1 dB and thermal shift of similar to 3.7 pm/degrees C. The proposed device endows the unique resonant peaks tuning capability more than similar to 18 nm by applying torsion stress, which has not been achieved in prior PCF-LPGs. From these novel thermo-optic and photo-mechanical properties, the proposed device can be applied for various components, including optical filters, attenuators, and sensors. (c) 2009 Elsevier B.V. All rights reserved.