摘要

A novel asymmetrical twin-core photonic crystal fiber was proposed, whose effective overlap core area A (eff) can be designed to synchronize the variation of Raman gain coefficient with respect to frequency. This fiber possesses a higher and flatter Raman gain efficiency coefficient curve r (R)=g (R)/A (eff) over a specified band of wavelength than a conventional fiber. Therefore, it is a good candidate of gain medium for a flat, broad gain band fiber Raman amplifier. It was numerically demonstrated that for the Raman gain efficiency r (R), relative fluctuations of less than 2.2% and 5.7% are achievable in the C (1530-1565 nm) band and L (1565-1625 nm) band, respectively.