Optical fiber communication 82021/2/19 aNvil dt 是受激辐射跃迁的 Einstain系数 三激光产生的条件 A (1) Amplifying Medium (2) Pumping Source (oPtical Feedback(Cavity) B粒子数反转 同值条件增益=损耗 0 n 2L ) RR2 小信号增益 a损耗系数1 - 8 Copyright Wang Yan 2021/2/19 Optical fiber communications 是受激辐射跃迁的Einstain系数 三 .激光产生的条件 A .(1) Amplifying Medium (2) Pumping Source (3) Optical Feedback (Cavity) B.粒子数反转 阈值条件 :增益 =损耗 2 21 21 1 dt N dN r st     = f B21 = r21 /  损耗系数 小信号增益 i 1 2 0 1 ln 21        = = + L R R g i