Polarization-maintaining (PM) Dense WDM filter coupler for combining or separating optical signals on PM fiber paths — the key passive in coherent transceiver test stations, DWDM-based PM sensor systems, and quantum-network add/drop nodes.
Construction is a thin-film WDM filter sandwiched between two PM collimators with slow-axis alignment. Operating wavelengths can be 1310 / 1550 nm (CWDM-style two-wavelength), any pair of ITU C-band channels (100 GHz or 200 GHz spacing), or single-channel add/drop. Insertion loss < 0.6 dB on the pass channel, isolation > 25 dB, return loss > 50 dB, polarization extinction ratio > 20 dB at the worst-case channel.
Standard PM fiber is Panda 1310 nm or 1550 nm grade with FC/PC or FC/APC connectorization (please specify when ordering). Custom wavelength pairs, custom ITU channels, custom pigtail lengths, and triplexer / quadruplexer variants are produced on request. Every unit ships with an IL / isolation / PER test report measured on a polarization-resolved OSA.
