Light propagation in dielectric loaded surface plasmon polariton waveguide (DLSPPW) resonant coupling devices operating at visible frequencies was experimentally investigated. The transmission characteristics of these devices were studied by leakage radiation microscopy. We show that a strong coupling between DLSPPWs can be achieved with nanoscale gaps. We demonstrate the operation of compact DLSPPW linear couplers and 3 dB power splitters. The performances of micro-DLSPPW racetrack resonators and signal drop filter are also discussed.