Abstract:In short length large-core SI-PDF fiber

leaky ray must be taken into account for transmitted power. A formula is developed to calculate the light power coupled from laser beam with different input angle to SI-PDF fiber. And the relation of output power with input angle of laser beam in 3m、67m、140m length fiber is achieved by measurement. The relationship curve between coupled power and input angle and angular attenuation of SI-PDF fiber as a function of input angle is obtained

which coupled power is decaying exponential as a function of input angle

angular attenuation increases with increase of input angle

at 12°

angular attenuation is 26 dB/km and 82 dB/km at 24°。