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Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping
Published on: March 20, 2017
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Fiber nonlinearity mitigation of WDM-PDM QPSK/16-QAM signals using fiber-optic parametric amplifiers based multiple
Optics Express
|March 10, 2018
Summary
Multiple optical phase conjugations (OPCs) effectively mitigate fiber nonlinearity in WDM systems. This technique enhances nonlinear thresholds and signal quality for QPSK and 16-QAM, outperforming single OPCs.
Area of Science:
- Optical Communications
- Nonlinear Optics
- Signal Processing
Background:
- Fiber optic transmission systems face performance degradation due to fiber nonlinearities.
- Optical Phase Conjugation (OPC) is a known technique for nonlinearity mitigation.
- Optimizing OPC placement and number is crucial for advanced modulation formats.
Purpose of the Study:
- To investigate the effectiveness of multiple optical phase conjugations (OPCs) for fiber nonlinearity mitigation.
- To compare the performance of multiple OPCs against single mid-span OPC and no OPC.
- To evaluate the impact of multiple OPCs on different modulation formats (PDM QPSK and PDM 16-QAM) and transmission distances.
Main Methods:
- Implementing multiple OPCs in Wavelength Division Multiplexing (WDM) transmission systems.
- Testing systems with 8 × 32-Gbaud Polarization Division Multiplexing (PDM) QPSK and PDM 16-QAM channels.
- Measuring nonlinear thresholds and Q² factors after transmission with varying OPC configurations.
Main Results:
- Multiple OPCs significantly improved nonlinear thresholds compared to no OPC and single mid-span OPC.
- For PDM QPSK over 3600 km, nonlinear threshold increased by ~5 dB (vs. no OPC) and ~2 dB (vs. mid-span OPC).
- For PDM 16-QAM over 912 km, nonlinear threshold increased by ~7 dB (vs. no OPC) and ~1 dB (vs. mid-span OPC).
- Modest improvements (0.2 dB to 1.1 dB) were observed in the best achievable Q² factors.
- Signal wavelength preservation was achieved with an even number of OPCs.
- The technique demonstrated transparency to modulation formats and effectiveness across different links.
Conclusions:
- Multiple OPCs offer a robust solution for fiber nonlinearity mitigation in WDM systems.
- The method is effective for both PDM QPSK and PDM 16-QAM, enhancing transmission performance.
- Multiple OPCs provide superior nonlinear threshold improvement compared to single OPC, enabling higher launch powers.
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