2×2 Coupler 80:20 SM Φ0.9mm Fiber Port 1:FC/APC 80% Port 2:20% Rx1310nm PD Port3:80% FC/APC Port4:20% Rx1490nm PD+ Rx1550nm PD 10dB Attenuation Port1 Port3:IL≤1.5dB@1310/1490/1550nm