220 fs Er-Yb:glass laser mode-locked by a broadband low-loss Si/Ge   saturable absorber
  We demonstrate femtosecond performance of an ultra-broadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon-dioxide/germanium structure that is fully compatible with CMOS processing. This device offers a reflectivity bandwidth of over 700 nm and sub-picosecond recovery time of the saturable loss. It is used to achieve mode-locking of an Er-Yb:glass laser centered at 1540 nm, generating 220 fs pulses, with the broadest output spectrum to date. 
F. J. Grawert, S. Akiyama, F. O. Ilday, J. Liu, J. T. Gopinath, H. M.   Shen, K. Wada, E. P. Ippen, L. C. Kimerling and F. X...