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Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping
Published on: March 20, 2017
Companding transform based SPM compensation in coherent optical OFDM transmission
Hwan Seok Chung1, Sun Hyok Chang, Kwangjoon Kim
1Optical Internet Research Department, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejon, 305-700, South Korea. chung@etri.re.kr
Optics Express
|January 26, 2012
Summary
We demonstrate a mitigation of fiber nonlinearity using a μ-law companding transform in optical OFDM transmissions. This technique reduces high peak-to-average power ratio (PAPR), improving OSNR margin by over 5.5 dB after 1,040 km transmission.
Area of Science:
- Optical Communications
- Signal Processing
- Nonlinear Optics
Background:
- High peak-to-average power ratio (PAPR) in optical Orthogonal Frequency Division Multiplexing (OFDM) signals exacerbates nonlinear impairments in optical fibers, primarily due to the Kerr effect.
- These nonlinear impairments degrade signal quality and limit transmission distances in coherent optical systems.
Purpose of the Study:
- To investigate the effectiveness of a μ-law companding transform in mitigating fiber nonlinearity in coherent optical OFDM transmissions.
- To analyze the impact of the companding parameter on noise enhancement and PAPR variations.
- To evaluate the performance improvements in both single polarization and polarization multiplexed systems.
Main Methods:
- The μ-law companding transform was applied to the time-domain OFDM signal to modify its amplitude profile and reduce PAPR.
- System performance was evaluated by measuring bit-error-rate (BER) under various conditions, including different companding parameters, analog-to-digital converter (ADC) resolutions, dispersion maps, and launch power tolerances.
- Experiments were conducted in both single polarization and polarization multiplexed transmission links over 1,040 km of standard single-mode fiber (SMF).
Main Results:
- The μ-law companding transform effectively reduced the PAPR of the OFDM signal, thereby mitigating fiber nonlinear impairments.
- The study presented the trade-offs between the companding parameter, noise enhancement, and PAPR variation.
- BER measurements demonstrated a significant improvement in the OSNR margin, exceeding 5.5 dB, after a 1,040 km SMF transmission.
Conclusions:
- The μ-law companding transform is a viable technique for mitigating fiber nonlinearity in coherent optical OFDM systems.
- The application of this transform enhances the OSNR margin, enabling longer transmission distances and improving overall system performance.
- The method offers a practical approach to overcome Kerr-effect-induced impairments in high-speed optical communication systems.
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