The 4 Ports 1310nm Polarization Maintaining Optical Circulator is a high-performance, non-reciprocal passive optical device designed to route light sequentially from Port 1 → Port 2 → Port 3 → Port 4, while precisely maintaining the polarization state of the transmitted signal. Operating at 1310 nm, this circulator offers low insertion loss, high isolation, and an excellent polarization extinction ratio (PER), ensuring superior performance in polarization-sensitive optical systems.