Four-degree hub switch module using multi-chip planar lightwave circuit integration technology for transparent ROADM ring interconnection

We have developed a PLC-based 32-wavelength 4-degree hub switch module, which consists of a broadcast coupler with a demultiplexer for local-drop, and a WSS with wavelength specific ports for local-add. The module size is 220/spl times/135/spl times/14 mm. The insertion loss of the express path in the WSS is 10.8 dB.