N-bit fully covered variable photonic time delay architectures for polarization mode dispersion compensation

Abstract

ABSTRACT N-bit programmable photonic time delay structures are proposed for the compensation of polarization mode dispersion (PMD). Our key design idea is to have one switchable differential group delay (DGD) module, that specially contains the zero DGD and the minimum DGD resolution step of , connected to the rest of the variable photonic DGD bit modules that offer DGD values of +2 N-2 to +2 . Our proposed variable photonic DGD architectures use 2x2 polarization maintaining optical switches or 90 degree polarization rotators to choose the desired DGDs. When all variable photonic DGD bit modules are attached to the polarization rotator, 2 N DGD values ranging from -(2 N-1 -1) to (2 N-1 ) are obtained. Our simulation study points out that compact programmable photonic DGD modules can be achieved by using materials with strong birefringence and our reflective configuration. In addition, materials with low wavelength sensitivity are preferred for use in broadband wavelength operation. Mirror-based programmable photonic DGD structures are also introduced. Keywords: Photonic time delay, Polarization mode dispersion, Differential group delay, Optical switches, Polarization rotators, Optical communications.