LightSmyth Technologies has introduced a fully integrated, single-mode compatible, coarse WDM (CWDM) multiplexer based on patented nanophotonic filtering technology. Its integrated CWDM multiplexer units are passively athermal and polarization insensitive to 0.2 dB. This new, integrated CWDM multiplexer is based on the silica-on-silicon planar waveguide format, requires chips of only 1 square cm, and is the first photonic device to productively harness the deep UV photolithographic patterning tools used in state-of-the-art electronics. LightSmyth’s underlying filtering technology may also be referred to as integrated holographics. Competing CWDM technologies use gratings or free-space thin-film filters. Grating devices can be integrated but require multimode outputs to produce low-loss flat-top passbands. Thin-film filters support flat-top passbands but cannot be monolithically integrated. LightSmyth’s new diffractive nanophotonic filtering engine uniquely and powerfully combines the integrability of gratings with the functionality of thin-film filters. Units for sampling and licenses to the underlying technology are available.