Gain enhancement in a hybrid plasmonic nano-waveguide with a low-index or high-index gain medium

• Published in: Optics express Vol. 19; no. 14; pp. 12925 - 12936
• Main Authors: Dai, Daoxin, Shi, Yaocheng, He, Sailing, Wosinski, Lech, Thylen, Lars
• Format: Journal Article
• Language: English
• Published: United States 04.07.2011
• Subjects: Computer Simulation; Computer-Aided Design; Electrical engineering, electronics and photonics; Elektroteknik, elektronik och fotonik; Equipment Design; Equipment Failure Analysis; Light; Models, Theoretical; Refractometry - instrumentation; Scattering, Radiation; Surface Plasmon Resonance - instrumentation; Systems Integration; TECHNOLOGY; TEKNIKVETENSKAP
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.19.012925

A theoretical investigation of a nano-scale hybrid plasmonic waveguide with a low-index as well as high-index gain medium is presented. The present hybrid plasmonic waveguide structure consists of a Si substrate, a buffer layer, a high-index dielectric rib, a low-index cladding, a low-index nano-slot, and an inverted metal rib. Due to the field enhancement in the nano-slot region, a gain enhancement is observed, i.e., the ratio ∂G/∂g >1, where g and G are the gains of the gain medium and the TM fundamental mode of the hybrid plasmonic waveguide, respectively. For a hybrid plasmonic waveguide with a core width of w(co)=30nm and a slot height of h(slot)=50nm, the intrinsic loss could be compensated when using a low-index medium with a moderate gain of 176dB/cm. When introducing the high-index gain medium for the hybrid plasmonic waveguide, a higher gain is obtained by choosing a wider core width. For the high-index gain case with h(slot)=50nm and w(co)=500nm, a gain of about 200dB/cm also suffices for the compensation of the intrinsic loss.