Design and characteristics of a novel narrow-band filter with the dual-core photonic crystal fiber

Abstract

A novel narrow-band filter based on the dual-core doped photonic crystal fiber is proposed. By optimizing structure parameters of the photonic crystal fiber, the index curves of the fundamental modes for the two cores are crossed at 1.55 μm and the wavelength-selective coupling is achieved. The characteristics of the filter are numerically simulated by the full-vector beam propagation method. And the simulation results show that the coupling length and the bandwidth of the filter are 16.4 mm and 9 nm at −3 dB loss, respectively. It demonstrates the advantages of the filter with a small size, a low transmission loss and the narrow-band width.