Fiber Bragg Grating Inscribed in Dual-Core Photonic Crystal Fiber

We present a direct fiber Bragg grating (FBG) inscribed in a dual-core photonic crystal fiber (DCPCF) using a conventional FBG inscription setup. The DCPCF-FBG generates a distinctive reflection spectrum that exhibits both a broad reflected peak and a significant sidelobe on its short wavelength side only. We systematically characterized the temperature and strain sensitivities of the DCPCF-FBG, and demonstrated its temperature and strain characteristics. The response of the DCPCF-FBG to bending was also investigated, which distinguishes it from a conventional FBG.