(a) Scheme of the 850 nm by a 4 μm chalcogenide (As2S3) rib waveguide on a silica substrate with a polytetrafluoroethylene (PTFE) over-cladding. (b) Tuning the frequency of the optical waves (here shown for the 1st Stokes wave) into the slow-light region at the band edge of the PBG leads to an enhancement of the nonlinear interactions. (c) Adjusting the pump frequency so that the Stokes frequency falls into the stopband, however, leads to an inhibition of the SBS process. (d) Illustration of the distribution of the density-of-states and the stopband for a one-dimensional PBG structure. The DOS increases towards the band edge of the structure and approaches zero in the stopband, which enabled the full suppression of any Stokes wave generation. (e) Scheme of how the enhancement effect can be cascaded using a multiband grating to form a Brillouin frequency comb. It illustrates the distinctive design of the multiband grating, matching the Brillouin shift and each having narrow bandwidth, so that multiple comb lines are aligned with the grating edges.