Bending dual-core photonic crystal fiber coupler

In this paper, we systematically study a designed structure of a bending dual-core photonic crystal fiber (PCF). We propose the controllable wavelength-selective coupling PCF. This coupler allows highly accurate control of the filtering wavelength. The different wavelengths can be selected by controlling the bending radius of the fiber. Coupling characteristics of novel bending wavelength-selective coupling PCF are evaluated by using a vector finite element method and their application to a multiplexer demultiplexer (MUX–DEMUX) based on the novel coupler is investigated. When the fiber length is 4168 μm, the bending radius of PCF couplers for 1.48/1.55 μm, 1.3/1.55 μm, 0.98/1.55 μm, and 0.85/1.55 μm is calculated, respectively, and the beam propagation analysis is performed. Different from the traditional wavelength-selective coupling PCF, the dual-core PCF is bent and it can realize the separation of multiple wavelengths.