We present an 8-channel integrated comb source spectral processor based on an arrayed-
waveguide grating with unconventional mounting, for improved aberration and sidelobes, in
loop-back configuration. The spectral processor is fabricated in a silicon nitride platform and
has a 100 GHz channel spacing.

For the realization of integrated microcomb-based systems, integrated photonic interposers
that connect, operate, and process the optical signals that transit between the many photonic
components are needed. In this work, the phase modulation characteristics of an 8-channel
integrated comb source spectral processor based on an arrayed-waveguide grating are
presented. The phase response of the device is characterized using optical frequency
domain interferometry.