Abstract

Polarization mode dispersion (PMD) is one of the most critical issues for the high-speed optical transmission system. To overcome the limitation imposed by PMD, various compensation techniques have been proposed.^1,2 However, these techniques could merely mitigate (rather than compensate) the effects of PMD due to its statistical property.² In order to evaluate the tolerance of the system’s performance, it is essential to emulate the statistical PMD of real fiber.Previously,several techniques have been proposed to emulate PMD statistically using polarization rotators and multiple hibi-fibers or birefringent crystals.^3,4 However, it is difficult to control and implement these techniques since they require a large number of sections for good distribution. In addition, the configuration of these emulators should be changed to emulate various statistics. Furthermore, the probability distribution generated by these emulators typically had much smaller value than the exact Maxwellian distribution at the tails (i.e., >3 ∆τ ).⁵ Thus, the system’s outage probabilities could be significantly underestimated in the rare DGD events. Recently, we have proposed a statistical PMD emulator using a variable-DGD-element.⁶ To generate PMD with exact Maxwellian distribution, we controlled the DGD value by using a microprocessor with special algorithm. However, this technique could not generate the higher-order PMD. In this paper, we propose a novel technique to emulate the statistical PMD including the higher-order PMD accurately. This technique utilizes variable-DGD-elements,polarization controllers, and a microprocessor. Using only three sections of DGD elements, the emulated PMD had a good statistical distribution at fixed wavelength in the second-order as well as in the first-order. In addition, unlike the previously proposed PMD emulators, the proposed technique could generate various statistics without changing its physical configuration.

© 2002 Optical Society of America