An embodiment of a waveguide has a Brillouin bandwidth, and includes cladding and a core. The cladding includes first layers of a first material, each first layer having a physical characteristic of approximately a first value, and includes second layers of a second material, each second layer having the physical characteristic of approximately a second value, the second layers alternating with the first layers such that the Brillouin bandwidth is wider than the Brillouin bandwidth would be if the cladding excluded the first layers or excluded the second layers. For example, the first and second cladding layers can be formed from different materials, or can be formed having different values of a physical characteristic such as thickness, acoustic velocity, or index of refraction. Such a waveguide can facilitate alignment of the waveguide's optical bandwidth with the waveguide's Brillouin bandwidth because the Brillouin bandwidth is widened compared to conventional waveguides.