Nonlocal PMD compensation in the transmission of non-stationary streams of polarization entangled photons

We study the feasibility of nonlocally compensating for polarization mode dispersion (PMD), when polarization entangled photons are distributed in fiber-optic channels.We quantify the effectiveness of nonlocal compensation while taking into account the possibility that entanglement is generated through the use of a pulsed optical pump signal

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

Diffusion of optical pulses in dispersion-shifted randomly birefringent optical fibers

An effect of polarization-mode dispersion, nonlinearity and random variation of dispersion along an optical fiber on a pulse propagation in a randomly birefringent dispersion-shifted optical fiber with zero average dispersion is studied. An averaged pulse width is shown analytically to diffuse with propagation distance for arbitrary strong pulse amplitude. It is found that optical fiber nonlinearity can not change qualitatively a diffusion of pulse width but can only modify a diffusion law which means that a root mean square pulse width grows at least as a linear function of the propagation distance.Comment: 11 pages, submitted to Optics Communication

Automatic DGD and GVD compensation at 640 Gb/s based on scalar radio-frequency spectrum measurement

We demonstrate what we believe to be the first real-time impairment-cancellation system for groupvelocity dispersion (GVD) and differential group delay (DGD) for a 640 Gb/s single-channel signal. Simultaneous compensation of two independent parameters is demonstrated by feedback control of separate GVD and DGD compensators using an impairment monitor based on an integrated all-optical radio-frequency (RF) spectrum analyzer.We show that low-bandwidth measurement of only a single tone in the RF spectrum is sufficient for automatic compensation for multiple degrees of freedom using a multivariate optimization scheme

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

A Comparison Between NRZ and RZ Data Formats with Respect to PMD-induced System Degradation

We quantify the PMD-induced system outage probability by means of numerical simulations for NRZ and RZ with proper comparative conditions and find that RZ performs better than NRZ. We also study the trade-off between power margin and acceptable PMD

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