Optical couplers having attachment features are disclosed. A typical coupler according to the present invention couples an optical signal from an optical fiber to a channel waveguide by overlapping the cores of the optical fiber and channel waveguide along a portion of their waveguide lengths, with a spacing distance between the cores of not more than 20 microns for single-mode light coupling, and not more than 100 microns for multi-mode light coupling. This is in contrast to a prior art coupler, which seeks to position the ends of the two cores in a facing relationship. In embodiments according to the present invention, attachment films may be disposed in the overlapping regions to provide advantageous coupling arrangements and new types of opto-electric devices.