Moshe Nazarathy

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We develop an analytic model of Coherent Optical Orthogonal Frequency Division Multiplexing (OFDM) propagation and detection over multi-span long-haul fiber links, comprehensively and rigorously analyzing the impairments due the combined effects of FWM, Dispersion and ASE noise. Consistent with prior work of Innoe and Schadt in the WDM context, our new(More)
We extend the well-known analogy between the problems of paraxial diffraction in space and dispersion in time to optical pulse compression and propose a time-domain analog to spatial imaging that allows for the distortionless expansion or compression of optical power waveforms. We call this new concept temporal imaging and derive equivalent expressions for(More)
We introduce a next-generation long-reach access optical network (35 dB loss budget +2 dB margin) delivering up to 40G/40G per passive 1:256 optical distribution network, supporting symmetrical 1 Gb/s rates per home user or up to 40 Gb/s for business users (e.g., enterprises, antenna sites). The proposed system is based on a novel spectrally efficient(More)
We introduce an efficient and accurate nonlinear compensator (NLC) for digital back-propagation (DBP) of coherent optical OFDM receivers, based on a factorization procedure for the Volterra Series Transfer Function (VSTF) with 3N degrees of freedom for N frequency samples. The O(N2) nonlinear compensation complexity of generic Volterra evaluation(More)
We demonstrate a real-time FPGA realization of dual polarization filter banks – this high-speed 2x25 GBd low-complexity core establishes feasibility of energy-efficient (multipliers count ~halved) HW architecture for a digitally sub-banded 170 Gb/s DFT-S OFDM receiver. OCIS codes: (060.1660) Coherent comm.; (060.2330) Fiber optic comm; Filter-banks;(More)
A self-coherent receiver capable of demultiplexing PolMUX-signals without an external polarization controller is presented. Training sequences are introduced to estimate the polarization rotation, and a decision feedback recursive algorithm mitigates the random walk of the recovered field. The concept is tested for a PolMUX-DQPSK modulation format where one(More)
We present yet another quasi-analytic model for an optically amplified receiver, comprising an optical preamplifier, an optical prefilter, a photodetector, and an electrical postfilter. Due to the square-law nonlinearity and its interaction with the linear preand postfilters, the understanding of this seemingly simple structure has been elusive, gradually(More)
We propose a new way to structure the digital signal processing for reduced guard-interval (RGI) OFDM optical receivers. The idea is to digitally parallelize the processing over multiple parallel virtual sub-channels, occupying disjoint spectral sub-bands. This concept is well known in the optical or analog sub-carrier domains, but it turns out that it can(More)
Subbanded digital signal processing (DSP) with underdecimated (Udeci) filter banks (FBs), is a recent DSP technique whereby the optical channel bandwidth is digitally sliced into multiple spectrally disjoint subbands (SBs) to be processed in parallel. In terms of DSP hardware (HW) architecture, digital subbanding amounts to an alternative mode of(More)
DFT-spread (DFT-S) coherent optical OFDM was numerically and experimentally shown to provide improved nonlinear tolerance over an optically amplified dispersion uncompensated fiber link, relative to both conventional coherent OFDM and single-carrier transmission. Here we provide an analytic model rigorously accounting for this numerical result and precisely(More)