Showing papers by "Norbert Hanik published in 2021"

Achievable Rates for Short-Reach Fiber-Optic Channels with Direct Detection.

Abstract: Spectrally efficient communication is studied for short-reach fiber-optic links with chromatic dispersion (CD) and receivers that employ direction-detection and oversampling. Achievable rates and symbol error probabilities are computed by using auxiliary channels that account for memory in the sampled symbol strings. Real-alphabet bipolar and complex-alphabet symmetric modulations are shown to achieve significant energy gains over classic intensity modulation. Moreover, frequency-domain raised-cosine (FD-RC) pulses outperform time-domain RC (TD-RC) pulses in terms of spectral efficiency for two scenarios. First, if one shares the spectrum with other users then inter-channel interference significantly reduces the TD-RC rates. Second, if there is a transmit filter to avoid interference then the detection complexity of FD-RC and TD-RC pulses is similar but FD-RC achieves higher rates.

Modeling Material Susceptibility in Silicon for Four-Wave Mixing Based Nonlinear Optics

Abstract: In We model the third-order material susceptibility $\overleftrightarrow \chi $[3] in silicon waveguides for integrated optics. Analysis of four- wave mixing in these waveguides requires an in-depth study of material nonlinearity - in contrast to modeling light propagation in fibers with the optical nonlinear Schrodinger equation. We include electronic and atomic lattice (Raman) responses of the material and present a relatively easy-to-use representation of the material susceptibility.