We describe recent progress on silica-based arrayed-waveguide grating
(AWG) add-drop multiplexers (ADMs) and multi-wavelength optical source
s for dense-WDM systems. We report a practical loop-back type 31-ch AW
G ADM and an all integrated-optic type 16-ch AWG ADM. We also describe
tunable AWG lasers and hybrid integrated multi-wavelength lasers whic
h employ waveguide gratings.