Fiber-Coupled Surface Plasmon Polariton Excitation in Imprinted Dielectric-Loaded Waveguides

Abstract

We present fiber-coupled dielectric-loaded plasmonic waveguides for 1.55 μm telecom wavelength fabricated by two-photon polymerization and nanoimprint lithography. The waveguide structures include 100-μm-long plasmonic waveguides connected on both ends to tapered dielectric waveguides used for end-fire coupling with optical fibers. The excitation of plasmonic waveguides is verified via polarization-resolved measurements of the overall transmission, demonstrating thereby that this technology is suitable in principle for the integration of plasmonic components into fiberoptics. Loss mechanisms are investigated and improvements suggested to reduce transmission losses and consequently increase the viability of practical application.

Bandgap-confined large-mode waveguides for surface plasmon-polaritons

“…Waveguide Fabrication Direct laser-writing using two-photon polymerization (2PP) is an attractive technology for the fabrication of two-and threedimensional structures on different substrates with resolutions down to and even less then 100 nm [37]. This approach has previously been demonstrated to be a reliable and fast method for fabricating functional plasmonic devices and components [17][18][19][20]38,39]. The substrate used for sample fabrication is a standard microscopy glass cover slide of 150 μm thickness coated with a 50 nm layer of gold.…”

“…1, are written into commercial negative-tone UV lithographic resist mr-NIL 6000.5 (microresist technology GmbH), which is spin-coated onto the surface of the gold film. This photoresist is wellsuited for the fabrication of plasmonic waveguide components, both by 2PP laser direct-writing [17,19] as well as nanoimprint lithography [38,39]. By spin-coating at 3000 rpm, a polymer film thickness of 500 nm is achieved.…”

Efficient Coupling Between Photonic and Dielectric-Loaded Surface Plasmon Polariton Waveguides With the Same Core Material

“…To circumvent this problem, a hybrid structure which consists of photonic and DLSPP waveguides is required. Photonic waveguides are used to transmit light signals, and DLSPP waveguides are used to control light signals [20]- [23]. In such a hybrid structure, it is essential to efficiently couple a DLSPP waveguide to a photonic waveguide.…”

“…The optimal loss of the end-fire coupling is about 1 dB. In the case of the hybrid structure based on photonic waveguides with the same core material as DLSPP waveguides, the DLSPP waveguides are tapered to match their dimensions to those of the photonic waveguides [22], [23]. This is because the core dimensions of the photonic waveguide are a few micrometers.…”

“…The loss of the coupling via the tapering was $3 dB. When the nanoimprint lithography resist mr-NIL 6000 of refractive index 1.523 was used as a core material, the height of the loaded dielectric, h d , as well as w d was increased, and h d was increased to the height of the core, h p [23]. In this case, l t was 50 m, and the coupling loss was $1.8 dB.…”