Metal-Insulator-Metal Waveguides With Self Aligned and Electrically Contacted Thin Semiconductor Cores Exhibiting High Optical Confinement and Low Loss

A metal insulator metal (MIM) waveguide structure which propagates a strongly confined sub-wavelength plasmon mode is proposed. In particular the structure permits electrical pumping of the waveguide core. The waveguide can in principle be fabricated with thin cores down to a few tens of nano meters wide. When quantum well material is employed, the waveguide core can be formed with self aligned quantum wire or quantum dot gain material. The performance of the proposed structure is compared to other plasmon mode and dielectric waveguide structures, and shown to provide significantly improved confinement of energy in the high index waveguide core. The implications of such waveguides when used as electrically pumped waveguides for optical amplifiers and nano-lasers is examined. It is shown that these electrically pumped waveguide structures offer the possibility of net modal gains in the region of 1900 cm^-1, and nano-lasers with intrinsic optical modulation frequencies reaching into the THz regime with minimum pump currents on the order of sixty micro-amps.