Extreme-dispersion-resistant optical true time delay line enabled by phase-domain pre-compensation

Area of Science:

• Photonics and Optical Engineering
• Signal Processing

Background:

• Optical true time delay lines (OTDLs) are crucial for various applications, but dispersion-induced signal distortion limits their performance and delay extension.
• Traditional OTDLs struggle with signal degradation due to chromatic dispersion, especially at higher data rates and longer delays.

Purpose of the Study:

• To develop an advanced OTDL architecture resistant to extreme dispersion.
• To enhance signal fidelity and overcome limitations in current dispersion-tuned OTDL systems.

Main Methods:

• A novel phase-domain pre-compensation technique is introduced to mitigate dispersion distortions.
• Dispersion effects are converted into power-fading-immune phase shifts.
• Polarization-diversity modulation is employed for pre-compensation, enhancing resistance to signal degradation.

Main Results:

• Experimental validation demonstrated significant improvements in signal quality within a high-dispersion OTDL link (-2021.7 ps/nm at 1550 nm).
• Error Vector Magnitude (EVM) was reduced from 17.47% to 10.93% for 2.5Gbaud 16QAM and from 16% to 8.86% for 1Gbaud 64QAM.
• The achieved signal quality closely approaches back-to-back performance levels.

Conclusions:

• The proposed phase-domain pre-compensation OTDL architecture offers superior resistance to dispersion-induced signal distortion.
• This innovative approach enables high-fidelity signal transmission in dispersion-limited OTDL systems.
• The findings pave the way for extended delay capabilities in future optical communication systems.