Sycamore IP Holdings LLC has added a third wave to its sole litigation campaign, filing complaints against AT&T (2:16-cv-00588), CenturyLink (2:16-cv-00589), Level 3 Communications (2:16-cv-00590), and Verizon (2:16-cv-00591). One patent (6,952,405) from a portfolio of 40 originally issuing to failed optical networking company Sycamore Networks, Inc. is at issue in the campaign. The ‘405 patent generally relates to encoding data for Ethernet over optical transport, with the defendants’ optical networking products targeted by the NPE.