Novel passive free space compact CWDM technology for outdoor applications

Recently CWDM system has emerged into one important platform for optical networks. Its low cost configuration helps the WDM technology applying into new applications such as access and FTTX networks, which are very sensitive to cost structure and cost efficiency. This brings additional challenges to the optical components for more different operation conditions. We introduce here a novel compact CWDM module for demultiplexer or multiplexer that has extremely low insertion loss and can work for outdoor applications. With unique technologies of thin film coatings and compact no-shift packaging, the premium performances are achieved with the savings on cost as well. The total loss of a 8-channel module is only 0.7 dB within the passband of ±7.5 nm, together with the PDL of 0.1 dB. The compact CWDM module is proven to be a low cost solution for metro, access, FTTX, CATV head end/node, and wireless networks.