Mahmoud Jazayerifar

Transmission of Multi-Band OFDM and Impulse Radio Ultra-Wideband Signals Over Single Mode Fiber

In this paper we examine the transmission of two types of ultra-wideband (UWB) signals, multiband orthogonal frequency division multiplexing (MB-OFDM) and impulse radio ultra-wideband (IR-UWB), over single mode fiber at 1550 nm. In order to investigate the impact of optical components such as laser diode, external modulator and single mode fiber on UWB signals, we develop mathematical models for these components. These models are experimentally verified and corresponding numerical parameter values are obtained by experiment. Using these models we discuss the transmission of two types of UWB signals over single mode fiber. A new figure of merit namely distortion factor is defined. Using this figure of merit the direct modulation of distributed feedback (DFB) laser diode and the external modulation with Mach-Zehnder modulator (MZM) are compared in terms of their impact on UWB signals. Using intensive simulation we also compare MB-OFDM and IR-UWB in terms of their sensitivity to the distortions of a UWB over fiber link using error vector magnitude (EVM) as a figure of merit. An EVM measurement is accomplished for a MB-OFDM over fiber link. The impact of IR-UWB pulse shape on its resistance to the nonlinearity of modulation transfer function is also investigated.

Highly efficient CW parametric conversion at 1550 nm in SOI waveguides by reverse biased p-i-n junction.

In this paper we present four-wave mixing (FWM) based parametric conversion experiments in p-i-n diode assisted silicon-on-insulator (SOI) nano-rib waveguides using continuous-wave (CW) light around 1550 nm wavelength. Using a reverse biased p-i-n waveguide diode we observe an increase of the wavelength conversion efficiency of more than 4.5 dB compared to low loss nano-rib waveguides without p-i-n junction, achieving a peak efficiency of -1 dB. Conversion efficiency improves also by more than 7 dB compared to previously reported experiments deploying 1.5 µm SOI waveguides with p-i-n structure. To the best of our knowledge, the observed peak conversion efficiency of -1dB is the highest CW efficiency in SOI reported so far.

Fiber optical parametric amplifiers in optical communication systems

The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed.

Kerr Nonlinearity Mitigation: Mid-Link Spectral Inversion Versus Digital Backpropagation in 5×28-GBd PDM 16-QAM Signal Transmission

We experimentally investigate Kerr nonlinearity mitigation of a 28-GBd polarization-multiplexed 16-QAM signal in a five-channel 50-GHz spaced wavelength-division multiplexing (WDM) system. Optical phase conjugation (OPC) employing the mid-link spectral inversion technique is implemented by using a dual-pump polarization-independent fiber-optic parametric amplifier and compared to digital backpropagation (DBP) compensation over up to 800-km in a dispersion-managed link. In the single-channel case, the use of the DBP algorithm outperformed the OPC with a Q-factor improvement of 0.9 dB after 800-km transmission. However, signal transmission was not possible with DBP in the WDM scenario over the same link length while it was enabled by the OPC with a maximum Q-factor of 8.6 dB.

Kerr nonlinearity mitigation in 5 × 28-GBd PDM 16-QAM signal transmission over a dispersion-uncompensated link with backward-pumped distributed Raman amplification.

We present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectral inversion of 5 × 28-GBd polarization-multiplexed 16-QAM signals. Signal quality factor (Q-factor) improvements of 1.1 dB and 0.8 dB were obtained in the cases of a single-channel and a five-channel wavelength-division multiplexing (WDM) system, respectively. The experimental results are compared to numerical simulations with good agreement. It is also shown with simulations that a maximum transmission reach of 2400 km enabled by the optical phase conjugator is possible for the WDM signal.

Performance Evaluation of DWDM Communication Systems With Fiber Optical Parametric Amplifiers

We derive analytical expressions for the performance of a long-haul DWDM communication system employing in-line phase insensitive fiber optic parametric amplifiers (FOPA). In our analysis the impairments of both transmission fibers and FOPAs are taken into account. The analytical model is verified with simulations. The performance of FOPA is compared with EDFA and it is shown that a broad band long-haul DWDM transmission system based on FOPAs as in-line amplifiers could be feasible.

Design and performance evaluation of an OPC device using a dual-pump polarization-independent FOPA

The performance of a polarization-independent fiber-based optical parametric amplifier is experimentally investigated in terms of amplification and wavelength conversion for optical phase conjugation applications using 5×28-GBd PDM 16-QAM signals. Good conjugated signal quality up to 13-dB gain is obtained.

Impact of SBS on polarization-insensitive single-pump optical parametric amplifiers based on a diversity loop scheme

We experimentally and numerically show that the Brillouin back scattering can result in signal distortions in diversity loop-based polarization insensitive single-pump fiber-optical parametric amplifiers, limiting the distortion-free gain to 10-15 dB for typical highly nonlinear fibers.

Characterization of a fiber-optical parametric amplifier in a 5 × 28-GBd 16-QAM DWDM system

The performance of a FOPA as inline-amplifier for 28-GBd 16-QAM signals at 20-dB gain in a 50-GHz 5-channel DWDM system is experimentally investigated. Less than 0.7-dB OSNR penalty at a BER of 1×10-3 was measured with 0-dBm per-channel output power.

Kerr nonlinearity compensation in a 5×28-GBd PDM 16-QAM WDM system using fiber-based optical phase conjugation

Effective Kerr nonlinearity mitigation is experimentally demonstrated using optical phase conjugation in the middle of an 800-km dispersion-compensated link for a 5-channel WDM 28-GBd PDM 16-QAM signal. A Q-factor improvement of 0.9 dB over no mitigation allows a BER<;3.8×10-3.