US Patent 10182275 Passive optical subassembly with a signal pitch router

Disclosed herein is wavelength-division multiplexer with an internal optical signal tuned by a mounted signal pitch router. In particular, disclosed is a wavelength-division multiplexing (WDM) optical assembly including an optical signal router, a WDM filter, and a signal pitch router. The WDM filter has a wavelength selective surface positioned proximate the second side of the optical signal router. The signal pitch router has a transmissive surface positioned proximate to a side of the optical signal router, and a second reflective surface opposite the transmissive surface. A depth of the signal pitch router establishes and tunes a pitch of a routing optical path within the optical signal router. This provides for easier, faster, more reliable, and more cost effective manufacturing and assembly of the WDM optical assembly.