Fig. 1. The scheme of transmitting DML overmodulation signal

Fig. 2. The scheme of overmodulation signal detection via RSSI

Fig. 3. The scheme of transmitting overmodulation signal via external modulator

Fig. 4. 25 Gbit/s NRZ PON and overmodulation test^[9]

Fig. 5. AMCC modulation depth and receive sensitivity^[9,12-14]

Fig. 6. AMCC modulation processing for coherent receiver^[14-15]

Fig. 7. Semi-active WDM architecture^[16-17]

Fig. 8. Semi-active WDM architecture using circulator^[20-21]

Fig. 9. Principle of PON silent window avoidance by overmodulation AMCC^[23]

Fig. 10. Experimental setup for testing crosstalk of overmodulation AMCC and data signal

Fig. 11. Signal after LPF^[23]

Fig. 12. Eye diagram of the 25 Gbit/s NRZ signal superimposed on the overmodulation signal^[23]

Fig. 13. Eye diagram of the 50 Gbit/s signal superimposed on the overmodulation signal

Fig. 14. Eye diagram of the 50 Gbit/s signal superimposed on the large overmodulation signal