DSP Based PMD Emulators for Built-in Testing of Coherent Optical   Receivers
  We propose discrete-time polarization mode dispersion (PMD) models that are compatible with the emerging coherent receiver techniques, and statistical sampling schemes for the model parameters. These models use multiple-input multiple-output (MIMO) finite impulse response (FIR) filters that are lossless and therefore lend themselves as perfect candidates for emulation of fiber channels suffering from PMD without polarization dependent loss (PDL). The concatenated composition of these filters resembles the continuous time lumped model of PMD channels and offers a flexible emulator and compensator structure in terms of computational complexity which constitutes the main bottleneck for real-time DSP applications. 
A. Gokcen Mahmutoglu, Alper T. Erdogan, Alper Demir
physics.optics