Agilent 11980A 是一款主机。 它与 Agilent 71400 系列或 Agilent 83810B 光波信号分析仪配合使用，可测量 DFB 激光源上的线性调频和频率调制（FM）。

11980A is a Mach-Zehnder interferometer of fixed delay. Used with an Agilent 71400 series or Agilent 83810B lightwave signal analyzer, it allows you to measure chirp and frequency modulation (FM) on DFB lasers. Traditional measurements of laser linewidth on single-line lasers can also be made.