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Estimation and compensation of sample frequency offset in coherent optical OFDM systems
1School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan, China. xwyi@uestc.edu.cn
Optics Express
|July 13, 2011
Summary
Synchronizing digital-to-analog converters (DAC) and analog-to-digital converters (ADC) is crucial for high-speed coherent optical OFDM systems. This study models sample frequency offset effects and proposes a compensation method verified through experimentation.
Area of Science:
- Optical communications
- Digital signal processing
Background:
- Coherent optical Orthogonal Frequency Division Multiplexing (OFDM) systems utilize digital-to-analog converters (DAC) and analog-to-digital converters (ADC).
- Synchronization of sample frequencies between DAC and ADC is critical for high-speed optical transmissions.
Purpose of the Study:
- To develop a channel model accounting for sample frequency offset (SFO) in coherent optical OFDM systems.
- To propose and experimentally validate a method for monitoring and compensating SFO.
Main Methods:
- A channel model was developed to incorporate the phase shift introduced by SFO, which is dependent on the subcarrier index.
- An experimental setup was used to verify the proposed SFO monitoring and compensation technique.
Main Results:
- The sample frequency offset introduces a phase shift proportional to the subcarrier index in coherent optical OFDM systems.
- The proposed monitoring and compensation method effectively addresses the impact of SFO.
Conclusions:
- Accurate synchronization of sample frequencies is essential for reliable high-speed optical OFDM communication.
- The presented approach provides a viable solution for managing SFO, potentially improving system performance by feeding monitoring results back to the receiver oscillator.
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