Period-Doubling in 10GHz Gain-Switched DFB Laser Diode

The distinct period doubling behaviour in a 10GHz gain-switched (GS) DFB laser is experimentally investigated in frequency domain and in time domain. The period doubling occurs as the frequency of the rf driving signal is close to or higher than the -3dB cutoff frequency of the DFB laser diode, and the amplitude of the rf driving signal required to achieve period doubling increases linearly with the increasing bias current of the laser diode.