PDM-16QAM transmission performance over uncompensated fiber links

Area of Science:

• Optical communication systems
• Digital signal processing
• Fiber optic transmission

Background:

• Wavelength Division Multiplexing (WDM) and Polarization Division Multiplexing-16-Quadrature Amplitude Modulation (PDM-16QAM) are advanced modulation techniques for high-capacity optical networks.
• Transmission performance in optical fibers is affected by signal baud-rate, fiber type, and nonlinear impairments.
• Optimizing spectral efficiency (4 b/s/Hz) requires careful consideration of these factors.

Purpose of the Study:

• To investigate the impact of signal baud-rate on propagation performance in WDM PDM-16QAM systems.
• To analyze the trade-offs between OSNR margin and nonlinear transmission penalties at different baud-rates.
• To evaluate system performance over uncompensated standard single-mode fiber (SMF) and non-zero dispersion-shifted fiber (NZDSF).

Main Methods:

• Simulations were conducted for WDM PDM-16QAM systems at a spectral efficiency of 4 b/s/Hz.
• Three baud-rates (16.25, 32.5, and 65 Gbaud) were tested, including soft-decision Forward Error Correction (FEC) overhead.
• Performance was compared for 100, 200, and 400 Gb/s data rates, considering nonlinear impairments on uncompensated links.

Main Results:

• Lower baud-rates (16.25 Gbaud) and narrower channel spacing (25 GHz) showed superior performance compared to higher baud-rates.
• The study identified an optimal trade-off between OSNR margin and nonlinear transmission penalty.
• Performance was evaluated across different data rates and fiber types (SMF and NZDSF).

Conclusions:

• Lower signal baud-rates are favored for optimizing propagation performance in WDM PDM-16QAM systems.
• A balance between OSNR margin and nonlinear penalties is crucial for effective data transmission.
• System design should consider baud-rate and channel spacing for enhanced optical network efficiency.