Author Affiliations
1School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China2State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876, Chinashow less
Fig. 1. Coherent receiving system based on digital signal processing
Fig. 2. Block diagrams of phase recovery algorithms. (a) VVPE algorithm; (b) BCPE algorithm
Fig. 3. Structure of parallel tree estimator
Fig. 4. BER performance versus Eb/N0 using different phase estimation algorithms and partial constellation diagrams. (a) BER performance; (b1) constellation diagram of VVPE (Eb/N0=2 dB); (b2) constellation diagram of BCPE (Eb/N0=2 dB); (b3) constellation diagram of VVPE (Eb/N0=7 dB); (b4) constellation diagram of BCPE (Eb/N0=7 dB)
Fig. 5. Carrier phase estimation after unwrapping. (a) VVPE (Eb/N0=2 dB); (b) BCPE (Eb/N0=2 dB); (c) VVPE (Eb/N0=7 dB); (d) BCPE (Eb/N0=7 dB)
Fig. 6. Noise phase variance versus Eb/N0 using different phase estimation algorithms
Fig. 7. Statistical distributions of noise phase. (a) Eb/N0=2 dB; (b) Eb/N0=7 dB
Fig. 8. BER performance versus Δν×Ts using different phase estimation algorithms
Fig. 9. BER performance versus average filter length using different phase estimation algorithms
Fig. 10. Experimental setup for 2.5 GBaud/10 GBaud QPSK system
Fig. 11. BER performance versus received optical power using different phase estimation algorithms. (a) Δν·Ts=4×10-5; (b) Δν·Ts=1×10-5
Fig. 12. Performance of fixed-point algorithm. (a) Comparison of the performance of fixed-point algorithm at different input signal bits under Matlab; (b) comparison of the performance of fixed-point algorithm between Matlab and Verilog
Resource | Utilization | Available | Utilization rate /% |
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LUT | 286606 | 1728000 | 16.59 | LUTRAM | 2232 | 791040 | 0.28 | FF | 353391 | 3456000 | 10.23 | BRAM | 64 | 2688 | 2.38 |
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Table 1. Resource utilization of VVPE algorithm with 8-bit input signal
Resource | Utilization | Available | Utilization rate /% |
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LUT | 186836 | 1728000 | 10.81 | LUTRAM | 1165 | 791040 | 0.15 | FF | 258312 | 3456000 | 7.47 | BRAM | 32 | 2688 | 1.19 |
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Table 2. Resource utilization of BCPE algorithm with 16-bit input signal