Fig. 1. Diagrams of signal patterns. (a) NRZ delayed 0.5 bit operation; (b) Manchester delayed 0.5 bit operation; (c) NRZ+Manchester signal operation

Fig. 2. Optical interconnection structure in data center

Fig. 3. Eye diagrams for data center bit rate of 10 Gbit/s. (a) NRZ signal from server 1; (b) Manchester signal from server 2; (c) superimposed NRZ+Manchester signal of the same server pair; (d) demodulated NRZ signal from receiving terminal of server 3; (e) demodulated Manchester signal from receiving terminal of server n-3

Fig. 4. Relationship between received optical power and bit error rate for signal with bit rate of 10 Gbit/s (without polarization angle error)

Fig. 5. Eye diagrams of demodulated NRZ and Manchester signals with different polarization angle errors at -22 dBm received optical power. (a)(b) Polarization angle error is 1°; (c)(d) polarization angle error is 2°; (e)(f) polarization angle error is 3°

Fig. 6. Influence of polarization angle error on BER of demodulated signals for 10 Gbit/s bit rate. (a) Demodulated NRZ signal; (b) demodulated Manchester signal

Fig. 7. Relationship between received optical power and BER for different bit rate (without polarization angle error)

Fig. 8. Influence of polarization angle error on BER of demodulated signals for 25 Gbit/s bit rate. (a) Demodulated NRZ signal; (b) demodulated Manchester signal