Fig. 1. Schematic diagram of O-band BDFA with bidirectional amplification under dual-circulator/coupler structure

Fig. 2. Experimental architecture for O-band BDFA single-fiber bidirectional amplification

Fig. 3. Schematics of experiments for testing light leakage degree and isolation degree. (a) Testing light leakage degree; (b) testing isolation degree

Fig. 4. Experimental results of light leakage degree and isolation degree. (a) Light leakage degrees of ports 1‒3 of circulator at different input powers; (b) isolation degree of ISO

Fig. 5. Performance of two signals in coupler structure. (a) ASE power at each port; (b) gain and NF versus input power at each port

Fig. 6. Performance of two signals in circulator structure. (a) ASE power at each port; (b) gain and NF versus input power at each port

Fig. 7. Evolutions of gains and NFs of two signals with pump power and output spectra at same input power

Fig. 8. Evolutions of gains and NFs of two signals with pump power