Disclosed is an optical waveguide including a waveguide core and waveguide cladding surrounding the waveguide core. The waveguide cladding includes at least one stack of cladding material layers positioned laterally adjacent to a sidewall of the waveguide core such that each cladding material layer in the stack abuts the sidewall of the waveguide core. Each of the cladding material layers in the stack has a smaller refractive index than the waveguide core and at least two of the cladding material layers in the stack have different refractive indices, thereby tailoring field confinement and reshaping the optical mode. Different embodiments include different numbers of cladding material layers in the stack, different stacking orders of the cladding material layers, different waveguide core types, symmetric or asymmetric cladding structures on opposite sides of the waveguide core, etc. Also disclosed is a method of forming the optical waveguide.