Elias Giacoumidis

Adaptive loading algorithms for IMDD optical OFDM PON systems using directly modulated lasers

A detailed study on the effectiveness of three proposed optical orthogonal frequency-division multiplexing (OOFDM) adaptive loading algorithms (ALAs) is conducted, addressing, for the first time, a number of crucial issues related to OOFDM directly modulated laser-based intensity-modulated and direct-detected passive optical networks (PONs). The ALAs include the power loading (PL), bit loading, and bit-and-power loading (BPL) algorithms. It is shown that in comparison with the most sophisticated BPL algorithm, the simplest PL algorithm is effective in escalating a single-channel OOFDM PON performance to its maximum potential. On the other hand, for multi-channel OOFDM PON and when employing a large number of subcarriers and high digital-to-analog/analog-to-digital converter sampling speed, the BPL algorithm should be adopted. The utilization of the three ALAs can also extend the optimum clipping ratio range up to at least 3 dB compared to a conventional identical modulation scheme.

Comparison of cost- and energy-efficient signal modulations for next generation passive optical networks

Extensive numerical investigations are undertaken to analyze and compare, for the first time, the performance, techno-economy, and power consumption of three-level electrical Duobinary, optical Duobinary, and PAM-4 modulation formats as candidates for high-speed next-generation PONs supporting downstream 40 Gb/s per wavelength signal transmission over standard SMFs in C-band. Optimization of transceiver bandwidths are undertaken to show the feasibility of utilizing low-cost and band-limited components to support next-generation PON transmissions. The effect of electro-absorption modulator chirp is examined for electrical Duobinary and PAM-4. Electrical Duobinary and optical Duobinary are power-efficient schemes for smaller transmission distances of 10 km SMFs and optical Duobinary offers the best receiver sensitivity albeit with a relatively high transceiver cost. PAM-4 shows the best power budget and cost-efficiency for larger distances of around 20 km, although it consumes more power. Electrical Duobinary shows the best trade-off between performance, cost and power dissipation.

Comparison of DSP-based nonlinear equalizers for intra-channel nonlinearity compensation in coherent optical OFDM

A novel versatile digital signal processing (DSP)-based equalizer using support vector machine regression (SVR) is proposed for 16-quadrature amplitude modulated (16-QAM) coherent optical orthogonal frequency-division multiplexing (CO-OFDM) and experimentally compared to traditional DSP-based deterministic fiber-induced nonlinearity equalizers (NLEs), namely the full-field digital back-propagation (DBP) and the inverse Volterra series transfer function-based NLE (V-NLE). For a 40xa0Gb/s 16-QAM CO-OFDM at 2000xa0km, SVR-NLE extends the optimum launched optical power (LOP) by 4xa0dB compared to V-NLE by means of reduction of fiber nonlinearity. In comparison to full-field DBP at a LOP of 6xa0dBm, SVR-NLE outperforms by ∼1u2009u2009dB in Q-factor. In addition, SVR-NLE is the most computational efficient DSP-NLE.

Reductions of peak-to-average power ratio and optical beat interference in cost-effective OFDMA-PONs

The peak-to-average power ratio (PAPR) and optical beat interference (OBI) effects are examined thoroughly in orthogonal frequency-division multiplexing access (OFDMA)-passive optical networks (PONs) at a signal bit rate up to

Range extension in coherent OFDM passive optical networks using an inverse Hammerstein nonlinear equalizer

sim 20,mathrm{{Gb}}/{hbox {s}}

40 Gb/s lane rate NG-PON using electrical/optical duobinary, PAM-4 and low complex equalizations

∼20Gb/s per channel using cost-effective intensity-modulation and direct-detection (IM/DD). Single-channel OOFDM and upstream multichannel OFDM-PONs are investigated for up to six users. A number of techniques for mitigating the PAPR and OBI effects are presented and evaluated including adaptive-loading algorithms such as bit/power-loading, clipping for PAPR reduction, and thermal detuning (TD) for the OBI suppression. It is shown that the bit-loading algorithm is a very efficient PAPR reduction technique by reducing it at about 1.2xa0dB over 100xa0Km of transmission. It is also revealed that the optimum method for suppressing the OBI is the TDxa0+xa0bit-loading. For a targeted BER of

Exceeding the Nonlinear Shannon-Limit in Coherent Optical Communications using 3D Adaptive Machine Learning

1 times 10 ^{-3}