Fiber-Based Programmable Picosecond Optical Pulse Shaper

We experimentally demonstrate a fiber-optic programmable optical pulse shaper based on time-domain binary phase-only linear filtering, which is capable of switching picosecond pulse shapes at unprecedented sub-GHz rates by simply updating the binary signal driving an electro-optic phase-modulator (EO-PM). The required binary phase-filtering functions are computed using a genetic algorithm (GA). One limitation of the binary phase-filtering approach is the inherent symmetry of the output temporal shapes. To generate fully arbitrary time-domain intensity profiles (including asymmetric temporal waveforms) we must employ a multi-level phase-filtering function. However, the size of the solution-space and complexity of the computation multiplies to manifolds as the number of levels in the phase-filtering function increases. Here we numerically demonstrate a simple strategy, by combining the Gerchberg-Saxton algorithm (GSA) and GA, for the fast computation of multi-level phase-filtering functions. The performance of this approach is numerically proven by generating different asymmetric pulse shapes of practical interest, assuming experimentally feasible design parameters.