Methods and apparatus are disclosed for forming annular lesions in tissue. The methods include introduction of an optical apparatus proximate to a tissue site, via, for example, a catheter. The optical apparatus includes a pattern-forming optical waveguide in communication with a light transmitting optical fiber. Energy is transmitted through the optical fiber, such that radiation is propagated through the optical fiber and the waveguide projects an annular light pattern, e.g., a circle or a halo.