An optical coupler having two refractive lenses for coupling an optoelectronic element and an optical medium to each other. One lens may be in contact with the optical medium. The refractive index of the one lens may be similar to the index of the optical medium. The optoelectronic element may be a light source or a detector. The light source may be a laser. The lenses may be glass ball lenses. One of the ball lenses may be a half ball lens. If the optical medium is an optical fiber, one of the lenses may a fiber stop for the fiber when inserted in a receptacle of the coupler.