June 7, 2010
      
                  
        
  Author(s)
  Mingming M. Feng,   Kevin L. Silverman,   Richard P. Mirin,   Steven T. Cundiff
 
       
            
    
    
        We describe an operating regime for passively mode-locked quantum dot diode laser where the output consists of a train of dark pulses, i.e., intensity dips on a continuous background. We show that a dark pulse train is a solution to the master equation for