Google Fiber has developed Super-PON, designed to go 50 kilometers. That's more than twice the reach of today's GPON. The illustration at left is a mid-sized city served by three central offices. Below, the same city using today's PON. It requires 16 COs.
Working units are in the field, probably from Adtran. That's not official, but I doubt DeSanti would have keynoted an Adtran event if an Adtran product wasn't close.
DeSanti made the surprising comment, "Aerial is prohibitively expensive due to policy restrictions of pole sharing with utility companies." The common wisdom is that aerial is much cheaper than underground.
That's true if you own the poles. Apparently, if you want to share the poles with the local electric or phone company, it's usually impractical in the U.S. I believe the actual rates are usually manageable but the setup and delays kill the project. (I can find counter-examples but DeSanti's comment is probably more typical.)
Super-PON was developed to bring down the costs of Google Fiber, which are believed to be much higher than Google expected. They have all but stopped building, including homes in Kansas City they took deposits for.
Dense Wave Division Multiplexing allows fewer fibers to serve more customers. Cost-saving micro-trenching is therefore practical. Fewer fibers also mean faster repairs of a cable cut. The system requires an amplifier. I believe a single amplifier covers all the fiber and is completely passive. I don't have the details confirmed as I write.
IEEE 802.3 is working on standardization. Google and Adtran see this as a natural extension of NG-PON2.
No news on when - or whether - Google Fiber will resume.