Various embodiments provide an apparatus and a method for operating the apparatus. The apparatus, in one embodiment, may include an optical waveguide located over a substrate, the optical waveguide having a first segment and a second segment. The apparatus may further include a single heating element configured to heat both the first segment and the second segment, wherein a light propagation direction at a point in the second segment differs by at least 90 degrees with respect to a light propagation direction at the point in the first segment.