An optical coupler that provides evanescent optical coupling includes an optical fiber and a waveguide. The optical fiber has a glass core, a glass inner cladding surrounding the glass core, and a polymeric outer cladding surrounding the glass inner cladding. The glass core and glass inner cladding define for the fiber a glass portion, which can be exposed at one end of the fiber by removing a portion of the polymeric outer cladding. The glass portion has a glass-portion surface. The waveguide has a waveguide core and a surface, and can be part of a photonic device. The glass portion of the fiber is interfaced with the waveguide to establish evanescent coupling between the fiber and the waveguide. Alignment features are used to facilitate aligning the fiber core to the waveguide core during the interfacing process to ensure suitable efficiency of the evanescent coupling.