Mid-infrared broadband all-optical wavelength converter in Ge20Sb15Se65 photonic crystal fiber with flattened dispersion

Abstract

A chalcogenide photonic crystal fiber (PCF) with flattened dispersion and high nonlinearity in mid-infrared (mid-IR) based on a triangular and circular lattice hybrid cladding structure is proposed. The structural parameters of the PCF are optimized by the full-vectorial finite-difference method. The numerical simulation results show: when d1 = 0.4 µm, d2 = 0.16 µm, d3 = 0.04 µm, Ʌ1 = 0.88 µm, Ʌ2 = 0.8 µm, Ʌ3 = 0.5 µm, the flatten and low dispersion is obtained in the wavelength range of 3.8–5 µm. The dispersion value is between ± 1.2 (ps/nm/km), and the maximum nonlinear coefficient is as high as 2464.2 km-1 W-1 at 2.5 µm. Based on the four-wave mixing (FWM) effect in the proposed PCF, the all-optical wavelength conversion performance is numerically analyzed. When the pumping wavelength is 4.02 µm, the 3 dB conversion bandwidth can reach 4833 nm (from 2.737 µm to 7.57 µm), and the maximum wavelength conversion efficiency is 12.12 dB. The proposed all optical wavelength converter is having large bandwidth and high conversion efficiency in mid-IR band due to the flat dispersion and high nonlinearity of the PCF, which has potential application in future space optical communication network and mid-IR photonic.