Transmitter mask testing for 28 GBaud PM-QPSK

We suggest a method for pass/fail testing of PM-QPSK transmitters. The test is based on mask testing with time-resolved EVM and accepts transmitters where individual impairments cause less than 0.5 dB OSNR penalty. The design of the test is performed by computer simulations followed by experimental verification of some key results

40-Gbaud 16-QAM transmitter using tandem IQ modulators with binary driving electronic signals

We propose a novel 16-quadrature amplitude modulation (QAM) transmitter based on two cascaded IQ modulators driven by four separate binary electrical signals. The proposed 16-QAM transmitter features scalable configuration and stable performance with simple bias-control. Generation of 16-QAM signals at 40 Gbaud is experimentally demonstrated for the first time and visualized with a high speed constellation analyzer. The proposed modulator is also compared to two other schemes. We investigate the modulator bandwidth requirements and tolerance to accumulated chromatic dispersion through numerical simulations, and the minimum theoretical insertion attenuation is calculated analytically

Polarization-Mode Disperion in Optical Fibers: Characterization, Transmission Impairments, and Compensation

The topic of this thesis is polarization-mode dispersion (PMD) in optical fibers and its impact on high-speed data transmission. The work can be divided into three parts which deal with the major aspects of PMD: characterization, transmission properties and compensation. Different methods have been developed for measurement of how the PMD is distributed or accumulated in long fiber cables. As the methods are particularly useful for identifying subsections with large PMD they could facilitate substantial improvements of poor links. The impact of PMD in transmission systems has also been investigated. In particular, we have quantified the benefit of applying a polarization interleaving scheme, which is a well known technique for suppression of nonlinear crosstalk in wavelength division multiplexed (WDM) systems. The effect of using solitons has also been experimentally quantified in both conventional and dispersion-managed, PMD-distorted systems. The results show that solitons are more robust to PMD than linear pulses and that dispersion-managed solitons can be even more robust than conventional solitons. Also the sensitivity to PMD for different data formats was investigated by means of numerical simulations. PMD-compensation is currently an intense research field. We present exact analytical expressions for the expected broadening of pulses affected by PMD. The theory also describes the benefit of using different optical PMD-compensation techniques. Also, by means of numerical simulations, we quantify the advantage of using various compensation techniques

Effect of nonlinearities on PMD system degradations

We review and discuss cross-phase modulation-induced polarization state changes in WDM systems, so called cross-polarization modulation, XPolM, and how it influences outage probabilities in polarization mode dispersion-limited system

Effect of nonlinearities on PMD system degradations

We review and discuss cross-phase modulation-induced polarization state changes in WDM systems, so called cross-polarization modulation, XPolM, and how it influences outage probabilities in polarization mode dispersion-limited system

Effects of Nonlinearities on PMD-Induced System Impairments

<para> It is well known that cross-phase-modulation-induced polarization rotation, cross-polarization modulation (XPolM), significantly degrades the performance of polarization-mode-dispersion (PMD) compensators. In this paper, the research on XPolM is reviewed, unique simulations of XPolM in the presence of walk off are presented, and some pitfalls are demonstrated with respect to choice of data streams in such simulations. Then, the authors discuss how XPolM affects PMD and PMD-induced outage probabilities (OP) in fiber-communication systems by providing analytical formulas for the OP with and without XPolM. Finally, the XPolM and PMD compensation are tied together by giving simple rules of thumb for when XPolM degrades PMD compensated systems, and PMD mitigation methods that are robust to XPolM are discussed. </para