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Dynamic line-by-line pulse shaping

Event Details

Event Dates: 

Wednesday, May 23, 2012 - 9:00am

Speaker Name(s): 

John Willits

Speaker Affiliation(s): 

Cundiff group
Seminar Type/Subject

Event Details & Abstract: 

In pursuit of optical arbitrary waveform generation (OAWG), line-by-line pulse shapers use dynamic masks that can be modulated at the repetition rate of an input pulse train.  The pulse-to-pulse control of the output pulse train with the waveform fidelity provided by line-by-line pulse shaping creates the most arbitrary waveform output possible, OAWG.  This thesis studies the dynamic effects of such a pulse shaper.  Pulse shaping theory is extended to include rapid waveform update for line-by-line pulse shaping.  The fundamental tradeoff between response speed and waveform fidelity is illustrated by several examples.  Line-by-line pulse shaping is demonstrated at the lowest known repetition rate of 890 MHz on a mode-locked titanium sapphire laser.  This pulse shaper relies on a virtual imaged phased array (VIPA) to obtain the necessary high spectral resolution.  The details of the VIPA's ideal and nonideal performance are analyzed, simulated and tested.  Individual frequency modes from the mode-locked titanium sapphire laser are also resolved using the same VIPA paired with a diffraction grating creating a 2-D spectral brush with a resolution of 357 MHz.  The advantages and nonideal effects of VIPA based pulse shaping are investigated.  Analysis of several high speed modulation techniques are explored.  The optical system required to separate adjacent comb lines into different single mode (SM) fibers necessary for several modulation techniques is designed and tested.  Finally, a novel transmission based pulse shaper is described which is able to circumvent the limitations of spectral recombination of a pulse.

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