... , raman amplifier, fiber sensor, coherent, telecommunications systems. CATEGORY: 1310nm&1550nm 3port polarization maintaining optical circulator(POLARIZATION MAINTAINING(PM)CIR),single stage, fast ... MAINTAINING(PM)CIR) ,single stage, both axis working. 1310nm&1550nm 4port polarization maintaining optical circulator(POLARIZATION MAINTAINING(PM)CIR),single stage, fast ...