A design for a novel broadband mode converter based on an asymmetric dual-core photonic crystal fiber is proposed. With adjusting the air-hole diameters of the inner rings in the cores and the index of the down-doped silica rods,broadband index-matched coupling is achieved. Numerical investigations demonstrate that a novel mode converter with operating wavelengths ranged from 1.45 μm to 1.61 μm at the loss of 0.5 dB and polarization-dependent loss which is lower than 0.28 dB can be realized in a fiber with a length of 5.9 mm