ICTON 2012 Tu.A5.5 978-1-4673-2227-0/12/$31.00 ©2012 IEEE 1 Surface Plasmon Interaction with Amplifying MQWs in Multilayer Kretschmann Structure: Wavelength-Scale Analysis by the Method of Single Expression Hovik V. Baghdasaryan, Tamara M. Knyazyan, Tamara T. Hovhannisyan and Marian Marciniak * Fiber Optics Communication Laboratory, State Engineering University of Armenia, 105, Terian str., Yerevan 0009, Armenia Tel: (374 99) 110 547, Fax: (374 10) 545 843, e-mail: hovik@seua.am * National Institute of Telecommunications, Department of Transmission and Optical Technologies, 1 Szachowa Street, 04-894 Warsaw, Poland ABSTRACT Surface plasmons are promising candidates in realization of short distance optical interconnection. However an unavoidable material loss even in noble metals prevents their wide application. Covering dielectric layer of some hundred-nanometer thickness deposited upon the thin metal layer in Kretschmann configuration can operate as a plasmon supported waveguide with lower loss than the bare plasmonic structure. To have an aim an essential increase of plasmonic waves’ propagation distance the dielectric-loaded Kretschmann structure with assistance of amplifying multiple quantum-wells (MQWs) upon it is suggested and analysed. Analysis is carried out for single mode regime of dielectric-loaded plasmonic waveguide. Wavelength scale modelling of optical properties of amplifying multilayer Kretschmann structure is performed by the method of single expression extended for the plane TM wave oblique incidence. Keywords: surface plasmon, Kretschmann structure, metal/dielectric, waveguiding layer, amplifying QWs, optical interconnects, method of single expression (MSE), numerical simulation. 1. INTRODUCTION Plasmonics is the modern field of science and technology that deals with the wavelength-scale structures and involves in developing of novel sensing and interconnecting devices within the nanometers scale [1-4]. Such devices consist of sub-wavelength structures comprising dielectric, semiconductor and metallic ultrathin layers or nanoparticles. The key feature of all plasmonic structures is sustaining specific light waves – so called surface plasmons (SPs) at the interface between a dielectric and metal. SPs, while propagating along the metal/ dielectric interface are evanescently confined in the perpendicular direction [1-5]. SPs possess a number of unique electromagnetic features making them highly attractive in creation of specific nano-optic devices. Field confinement to the metal/dielectric interface permits to realise optical waveguides with size much less than conventional ones. The possibility of transferring an optical wave in the vicinity of metal’s surface will permit to realise combined twofold purpose electro/optical conductor/waveguide. The strong confinement of optical wave near the metal/dielectric interface permits to realise near-field sensors of high resolution and to exploit local electric field enhancement to manifest nonlinear phenomena up to single molecules detection. The field of plasmonics has attracted much interest in the context of highly integrated nanophotonic devices, material science, biological sensing, spectroscopy, medical diagnostics, environmental monitoring, food safety and others [1-7]. There exist different techniques for plasmonic waves excitation, which are: by means of diffraction gratings, prism couplers and optical waveguides [4-6]. Depending on the specific problem solution different methods of excitations are used. There are two main areas of SPs’ application: sensing and interconnecting with different active and passive plasmonic elements. While application of plasmonic sensors now is enough advanced, an application of SPs in interconnection is still in the stage of investigation. The high activity in this area is dictated by needs of contemporary microelectronics [8]. In CMOS structures operating at high frequencies application of optical interconnects promise essential advantages in communication rates and possibility of cancellation of interchannel interference. Plasmonic communication will be highly suitable for CMOS technology as an optical link can exploit the same wires, which are in use for electrical links. However, inherent loss even of noble metals restricts the communication distances up to the micron range. To overcome this problem it was suggested to exploit an optical gain medium adjoining to the metallic layer [9-12]. However, this approach does not offer the possibility of essential increase of SPs’ propagation distances. The increase of propagation distance is only about 30% – 50% that gives the distances up to 1.5 µm [11]. An alternative approach is usage of dielectric-loaded SP waveguides [13-17]. In that waveguides, supported by SPs, a thin dielectric layer deposited upon a metallic layer allows guided modes with propagation loss about one order of magnitude lower than that of the SP mode [18]. In recent works a dielectric layer of two hundred nanometers thickness upon a thin silver layer of Kretschmann structure indicated the loss lower than of bare