International audience—The joint use of peak-to-average power ratio (PAPR) reduction and linearization via digital predistortion is investigated in this letter, with the view to improve the performances of coherent optical OFDM (CO-OFDM) systems employing a semiconductor optical amplifier (SOA). PAPR reduction is performed via Wang's nonlinear companding transform (WNCT), which has been recently pointed out as a pertinent choice for optical communications, and a Filter Lookup Table (FLUT) scheme is considered for linearizing the transmitter. Experimental results prove the effectiveness of the proposed scheme, as a lower EVM is achieved with respect to system implementations using only PAPR reduction or linearization

This paper presents a Volterra-based method of behavioral modeling for the I/O buffers of digital ICs. While this technique brings a slight improvement in accuracy over previous ones, its main strength is a greater degree of generality. With a modeling approach less dependent on the nature of the devices and more easily extendable to include the effects of multiple inputs one may hope better meet the challenges of advancing technology. The proposed models can be obtained from device port transient responses only and can be easily implemented in any simulation environment, including SPICE-based circuit description software. Two illustrative examples conclude the paper.

analysis of a parallel two-box digital polynomial predistorter for an SOA-based CO-OFDM system. Optics Communications, Elsevier, 2017, 402, pp.442 -452. 10.1016/j.optcom.2017 The linearization performance of various digital baseband pre-distortion schemes is evaluated in this paper for a coherent optical OFDM (CO-OFDM) transmitter employing a semiconductor optical amplif er (SOA). In particular, the benef ts of using a parallel two-box (PTB) behavioral model, combining a static nonlinear function with a memory polynomial (MP) model, is investigated for mitigating the system nonlinearities and compared to the memoryless and MP models. Moreover, the robustness of the predistorters under different operating conditions and system uncertainties is assessed based on a precise SOA physical model. The PTB scheme proves to be the most effective linearization technique for the considered setup, with an excellent performance-complexity tradeoff over a wide range of conditions.

International audienceDiscrete-time Laguerre series are a well known and efficient tool in system identification and modeling. This paper presents a simple solution for stable and accurate order reduction of systems described by a Laguerre model

International audienceModern Signal and Power Integrity (SI/PI) verification flows rely on accurate models for complex I/O-buffers that drive and receive electrical signals on high-speed channels. The sheer density of modern integrated circuits makes detailed transistor-level descriptions computationally cumbersome to the point where they become unusable for system-level simulations. Fortunately, transistor-level descriptions may be replaced with more compact representations that approximate the input/output buffers behavior with considerable accuracy while providing a simulation speedup of several orders of magnitude. Known as behavioral models, surrogate models or macromodels, these computationally efficient equivalents have become a de-facto industry standard in SI/PI simulations. This paper presents an overview of the state-of-the-art in I/O-buffer behavioral modeling, introducing the main features of both standard and emerging solutions. Open issues and future research directions are also discussed