Abstract-Mode-dependent loss (MDL) is known to be a major issue in space-division multiplexed (SMD) systems. Its effect on performance is complex as it affects both the data carrying signal and the accumulated amplification noise. In this paper we propose a procedure for characterizing the MDL of SDM systems by means of standard measurements that are routinely performed on SDM setups. The figure of merit that we present for quantifying MDL incorporates the effect on the transmitted signal and the noise and is directly related to the spectral efficiency reduction. , a workable characterization of MDL in a way that relates an easily measurable parameter with the corresponding effect on system performance is not available yet. A major issue in the case of SDM systems is the very definition of a single MDL parameter. While in the case of single-mode fibers the magnitude of MDL is fully characterized by the power-ratio between the least and the most attenuated states of polarization, in the multi-mode case a multiplicity of parameters is required to unequivocally quantify the magnitude of MDL. In this case, the obvious extension where the MDL is quantified by the power ratio between the least and the most attenuated states in the hyperpolarization space (which consists of all spatial and polarization modes), is incomplete and cannot be unequivocally related to performance penalty. In this paper we introduce a simple and efficient approach for quantifying the effect of MDL, which is based on the definitions of a MDL vector Γ and noise degree of coherency vector Γ ′ , which will be introduced later in this paper. We look at the reduction in spectral efficiency caused by MDL in the case where the mode-averaged signal and noise powers at the receiver are specified. We show that in the regime of small to moderate MDL, the MDL-induced reduction in spectral efficiency per mode can be expressed as
Index Terms-Optical
We study the performance of a simple optical receiver for use with polarization multiplexed transmission in the presence of polarization dependent loss (PDL). The receiver is based upon filtering of each of the channels with a polarizer that is orthogonal to the other channel, such that interference due to loss of orthogonality is avoided at the expense of a reduction in the detected signal to noise ratio. In spite of its simplicity, this receiver is shown to perform almost as well as the optimal maximum likelihood receiver, and much better than receivers that are based on conventional polarization splitting.
We propose a space-time coding scheme designed to increase the tolerance of fiber-optic communications systems to polarization-dependent loss (PDL). A notable increase in the tolerable amount of average link PDL is achieved without affecting the complexity of the overall optical communications link. Other advantages include seamless integration with the broadly deployed blind equalization modules relying on the constant modulus algorithm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.