Fiber optic amplification in a spectrum of infrared electromagnetic radiation is achieved by creating a chalcogenide photonic crystal fiber (PCF) structure having a radially varying pitch. A chalcogenide PCF system can be tuned during fabrication of the chalcogenide PCF structure, by controlling, the size of the core, the size of the cladding, and the hole size to pitch ratio of the chalcogenide PCF structure and tuned during exercising of the chalcogenide PCF system with pump laser and signal waves, by changing the wavelength of either the pump laser wave or the signal wave, maximization of nonlinear conversion of the chalcogenide PCF, efficient parametric conversion with low peak power pulses of continuous wave laser sources, and minimization of power penalties and minimization of the need for amplification and regeneration of pulse transmissions over the length of the fiber, based on a dispersion factor.