Isaac Sackey

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.

1.024 Tb/s wavelength conversion in a silicon waveguide with reverse-biased p-i-n junction

We experimentally show an all-optical wavelength conversion of 8 × 32-GBd single-polarization 16QAM signals using a silicon nano-rib waveguide. The application of reverse biasing of the p-i-n junction of the waveguide allows a conversion efficiency of -8.5 dB with a measured 3-dB optical bandwidth of about 40 nm. Using digital coherent reception, it is shown that the receiver optical signal-to-noise ratio penalty, at a bit-error ratio of 1 × 10-3, of the wavelength-converted signals over all eight channels was less than 0.6 dB with reference to their respective back-to-back signal channels.

Performance Evaluation of a Silicon Waveguide for Phase Regeneration of a QPSK Signal

In this paper a silicon-on-insulator nanorib waveguide with reverse-biased p-i-n-junction is used to experimentally demonstrate phase-sensitive amplification based on four-wave mixing for the realization of an in-line four-level phase-regenerator. Phase regeneration of a 14-GBd quadrature phase-shift keying signal is demonstrated for the first time employing a silicon waveguide as phase sensitive amplifier. The regenerator is placed in a 1040-km dispersion-managed link and it is shown that phase noise accumulation in the transmission link can be reduced by the use of the in-line silicon-based phase-regeneration.

Non-reciprocal gain due to counter-propagating pumps in a polarization-independent FOPA with diversity loop

We investigate limitations set on single-pump polarization-independent fiber-optical parametric amplifier (FOPA) using polarization-maintaining highly nonlinear fiber in a diversity loop. We show that Brillouin scattering between the counter-propagating pumps yields polarization-dependent gain if an asymmetric local dispersion profile is present.