According to IHS, the market for sensors for wearables will double in 2015 and grow sevenfold until 2019:
http://www.eetimes.com/document.asp?doc_id=1324363
At least for sensors which detect light in one or the other way, POET could be in that game. And there's always some processing power needed behind a sensor. For wearables, like for all kinds of mobile devices, power saving is a good thing – again something where POET could help.