International audienceHeterodyne optical feedback on class-B solid state laser is applied for characterizing dielectric-loaded surface plasmon-polariton waveguides (DLSPPW) at telecom wavelength. Near-field optical images recorded on a series of DLSPPWs are compared to numerical models (mode-solver and finite-difference time-domain). IntroductionCompared to other surface plasmon-polariton (SPP) waveguides, DLSPPWs are characterized by a good compromise between efficient light squeezing on sub-wavelength structures and reasonably long propagation range [1]. DLSPPWs can be easily fabricated using e-beam or photolithography. Moreover the dielectric ridge on the top of the metal could also be structured to implement passive or active functionalities [2]. Therefore, DLSPPW are very promising components for high-density optical circuits or interconnects between integrated circuits and optical links. Improvements on DLSPPWs are still underway to further increase the propagation length in order to obtain very long-range DLSPPWs with propagation length exceeding few hundred microns [3]. Experimental setup and results Polymer layer (resin SAL 601 negative resist; thickness h stripe =600nm; refractive index n=1.68 @ 633nm) was spin-coated on 50-nm-thick gold film evaporated on a silica substrate. The polymer was micro-structured by e-beam lithography to pattern a series of rectangular micro-stripes with widths varying between w stripe =500nm up to 4µm. A funnel, located at the beginning of each stripe waveguide, was added for efficient light coupling thanks to adiabatic effective index matching (figure 1a)
