Design of an Optical Power and Wavelength Splitter Based on Subwavelength Waveguides

A plasmonic T-shaped metal-insulator-metal waveguide followed by two or four output waveguides with ultranarrow silica slits is proposed to serve as an optical power and wavelength splitter in compact footprint. When the lengths of all silica slits are identical, uniform transmittances and identical center wavelengths are observed at all the output waveguides, and they can be tuned by changing the positions and the lengths of the slits, respectively. In addition, the proposed structure can also be used as a multichannel wavelength splitter by employing the resonance characteristics of the slits. When the silica slits are different in length, a transmission peak with a specific center wavelength will be achieved at the corresponding output waveguide, such that different wavelengths are splitted, respectively. The performances of the proposed power/wavelength splitter are demonstrated by using the finite-difference time-domain method.