递减型 meaning in Chinese

decrescendo

Three shaped profiles ( parabola , linear , and exponential ) have been considered . the exponential dispersion profile fiber loop is optimal for the propagation and compression of picosecond pulse . on the contrary , the parabola dispersion profile fiber loop is optimal for femtosecond pulse due to the high order effects such as the third order dispersion ( tod ) , stimulated raman scattering ( srs ) and self steeping ( ss )
( 3 )研究不同色散递减类型(抛物线递减、线性递减、指数递减)光纤构成的环形腔中传输的特性，发现其色散曲线为指数递减型光纤有利于皮秒光脉冲的传输与压缩；而对于飞秒脉冲，由于三阶色散( tod ) 、脉冲拉曼自散射( srs )及自变陡( ss )等高阶非线性效应的影响，情况恰恰相反；色散曲线为抛物线递减型的光纤构成的光纤环最有利于脉冲传输与压缩。