An integrated device for a wavelength division multiplexing passive optical net (WDM-PON) upgrade has been developed. It is based on a novel concept using an AWG for multiplexing two or more wavelength bands. Here, a broadcast wavelength (1.31 mu m) delivered by a distributing horn was multiplexed onto an 8-channel WDM spectrum (1.55 mu m) delivered by a flat top AWG. Temperature tolerant devices were fabricated using a silica technique.