Conjugate nonlinear-optical loop mirror (Conj-NOLM)-based phase-preserving multilevel amplitude regenerator

Area of Science:

• Optical communications
• Nonlinear optics
• Photonics

Background:

• Optical transmission links suffer from amplitude and phase distortions caused by noise and nonlinear effects.
• Existing regeneration schemes often fail to address both amplitude and phase distortions simultaneously or efficiently.

Purpose of the Study:

• To propose and evaluate a novel phase-preserving multilevel amplitude regenerator.
• To enhance the performance and power efficiency of optical signal regeneration.
• To extend the reach of optical transmission links.

Main Methods:

• Cascading two nonlinear-optical loop mirrors (NOLMs) with an intermediate optical phase conjugator (OPC).
• Joint parameter optimization of NOLM units for phase distortion cancellation and power efficiency.
• Numerical simulations to assess regeneration performance in a simulated transmission link.

Main Results:

• The proposed scheme effectively cancels introduced phase distortion.
• Combined NOLM and OPC operation compensates for both amplitude and phase distortions.
• Achieved over 100% reach extension compared to un-regenerative and mid-span OPC links.
• Demonstrated effectiveness against amplified spontaneous emission (ASE) noise and Kerr-induced nonlinear distortions.

Conclusions:

• The novel phase-preserving multilevel amplitude regenerator offers superior performance.
• The integrated NOLM-OPC subsystem provides efficient compensation for signal impairments.
• This approach significantly enhances the transmission link's effective reach.