<title>Optimization of reconstruction algorithm for cross-phase modulation frequency-resolve optical gating in a high birefringence microstructured fiber</title>

Abstract

We implemented a frequency resolved optical gating (FROG) measurement method using cross-phase modulation (XPM) in a microstructured optical fiber (MOF). This method allows for measuring shorter pulses or pulses with lower energy than XPM FROG in a conventional fiber. High birefringence of the MOF must be accounted for. We found that the standard FROG reconstruction algorithm, the generalized projection (GP), failed for this setup and we used the genetic algorithm (GA) instead. Although GA is much slower than GP, it is a global search method which is less prone to get stuck to local minima. GA has several parameters that need to be adjusted. In this article, we present the optimization process and the optimal parameters for theoretically simulated data. FROG error less than 1 × 10^-4 is achieved in less than 30 minutes with our 32-bit program running on a single Cpu AMD Athlon64 3200+ under 32-bit Windows XP SP2.