Optical Phase Conjugation in a Silicon Waveguide With Lateral p-i-n Diode for Nonlinearity Compensation

Abstract

In-line optical phase conjugation is a well-known technique to enhance the received signal quality through nonlinearity compensation. Being able to implement the conjugation in cm-scale highly nonlinear devices, which can be integrated on a silicon chip could potentially lead to several benefits in terms of small footprint and co-integration with linear signal processing functionalities, as well as lower power consumption. Here, we focus on silicon waveguides to implement the optical phase conjugation through four-wave mixing. The challenges in terms of conversion efficiency imposed by the presence of nonlinear loss are tackled by using a lateral p-i-n diode along the waveguide. When the diode is reverse biased, the conversion efficiency can be effectively enhanced by the decrease in free-carrier absorption. Low-penalty conversion can therefore be achieved for WDM signals and the highquality of the generated idlers is critical in demonstrating a 1-dB Q-factor improvement through optical phase conjugation in a 5 WDM channel 16-QAM transmission system after 644km of dispersion compensated transmission. The performance improvement enables a performance better than the HD-FEC threshold for all the transmitted channels.

Characterization and Optimization of Four-Wave-Mixing Wavelength Conversion System

“…As a result, for specific system parameters there exists an optimal input power P in which maximizes the received idler SNR. These trends are consistent with the preliminary analysis of [5] and [6], where similar power dependence have been demonstrated for the Q-factor and the achievable information rate (AIR) for inputs with maximum OSNRin, respectively.…”

Lumped Compensation of Nonlinearities based on Optical Phase Conjugation

“…Using Eq. ( 2), the complex field amplitude A has the following form after transmission in the first span (left of OPC): (6) where the subscripts on the operators indicate in which part of the link (span 1 or span 2) the effects have been experienced. After propagation in the first span, the field is conjugated using OPC and the phase distortions are reversed, resulting in:…”

Symmetry Enhancement Through Advanced Dispersion Mapping in OPC-Aided Transmission

“…3c, DU1). As a result, the nonlinearity is mismatched between the spans, and the OPC compensation gains are known to be limited for such link design [6], [7]. The second scenario is a dispersion managed system (Fig.…”