Mode-Locked Chip Laser using Waveguide Arrays
  We demonstrate theoretically that robust mode-locking can be achieved on a semiconductor chip with a waveguide array architecture. The waveguide arrays are used as an ideal saturable absorption mechanism for initial noise start-up as well as pulse shaping and stabilization. The cavity gain is provided by an injection current and forward biasing of the semiconductor material. The technology can be integrated directly with semiconductor architectures and technologies, thus allowing for the potential of an on-chip, broadband device. 
Xiao Zhang, Matthew Williams, Steven T. Cundiff, J. Nathan Kutz
physics.optics