Dynamic spectral line-by-line pulse shaping by frequency comb shifting

Traditionally, reconfigurable optical pulse shaping is performed by using programmable spatial light modulators or tunable optical attenuators and phase shifters. We propose a technique to achieve tunability in the line-by-line pulse-shaping regime by controlling the offset frequency of an optical frequency comb. The method requires a high-spectral-resolution line-by-line shaper with channel spacing equal to a submultiple of the comb spacing. As a particular example, we numerically analyze tunable pulse-repetition-rate multiplication by grating-based line-by-line pulse shaping using a fixed phase-only mask.