New designs of optical devices, particularly for adding or dropping a selected wavelength or a group of wavelengths are disclosed. In one aspect, no collimators or the like are used. Instead, two fibers are coupled effectively via a concave mirror. Depending on the shape of the concave mirror that may have a shape substantially similar to a portion of an oblate spheroid or sphere, the facets or tips of these two fibers are positioned near or upon the foci of the oblate spheroid or the center of the sphere. Utilizing the special characteristics of the concave mirror, these two fibers can be optically coupled with minimal loss and without the use of any optical collimators.