Near field measurements of optical channel waveguide structures

Near field scanning optical microscopy (NSOM) has been used to investigate the guided mode intensity distribution in optical channel waveguides, phase-matched directional couplers, and symmetric Y-junctions. A near field measurement of the guided mode intensity profile across the optical channel waveguide has been performed and compared with model calculations. The near field guided mode intensity profiles above the waveguides were measured as a function of distance along the propagation direction of both a directional coupler and a Y-junction, providing a near field view of the spatial evolution of optical power in these structures.