Abstract: Advances in femtosecond lasers that have made it possible to generate pulses with durations on the order of one optical cycle have also made it possible to control the phase of the underlying electric field waveforms. This new capability is in turn leading to more accurate clocks and to greater precision in spectroscopy by creating broadband frequency combs. Further, by spatially resolving and rapidly modulating the many individual comb frequencies, one can generate truly arbitrary optical-frequency electric-field waveforms. This talk will describe advances toward these goals based on Ti:sapphire and fiber laser technologies to cover the wavelength range of 2µm–500nm. Erich P. Ippen received his Ph.D. from the University of California, Berkeley, in 1968 and worked at Bell Labs in Holmdel, N.J., from 1968 to 1980 before joining the faculty of MIT where he is now Elihu Thomson Professor of Electrical Engineering and professor of physics. He has received major awards from IEEE, the Optical Society (OSA), the American Physical Society and SPIE; and he is a member of the National Academy of Sciences, the National Academy of Engineering and the American Academy of Arts and Sciences. His current research interests include femtosecond optical clock and arbitrary waveform technologies, ultrashort-pulse fiber devices, ultrafast studies of materials and devices, and nanophotonics.