Improved Plasmonic Filter, Ultra-Compact Demultiplexer, and Splitter

Abstract

In this paper, metal insulator metal (MIM) plasmonic slot cavity narrow band-pass filters (NBPFs) are studied. The metal and dielectric of the structures are silver (Ag) and air, respectively. To improve the quality factor and attenuation range, two novel NBPFs based on tapered structures and double cavity systems are proposed and numerically analyzed by using the two-dimensional (2-D) finite difference time domain (FDTD) method. The impact of different parameters on the transmission spectrum is scrutinized. We have shown that increasing the cavities' lengths increases the resonance wavelength in a linear relationship, and also increases the quality factor, and simultaneously the attenuation of the wave transmitted through the cavities. Furthermore, increasing the slope of tapers of the input and output waveguides decreases attenuation of the wave transmitted through the waveguide, but simultaneously decreases the quality factor, hence there should be a trade-off between loss and quality factor. However, the idea of adding tapers to the waveguides' discontinuities of the simple structure helps us to improve the device total performance, such as quality factor for the single cavity and attenuation range for the double cavity. According to the proposed NBPFs, two, three, and four-port power splitters functioning at 1320 nm and novel ultra-compact two-wavelength and triple-wavelength demultiplexers in the range of 1300-1550 nm are proposed and the impacts of different parameters on their performances are numerically investigated. The idea of using tapered waveguides at the structure discontinuities facilitates the design of ultra-compact demultiplexers and splitters.

Multiple Fano-Like MIM Plasmonic Structure Based on Triangular Resonator for Refractive Index Sensing

“…There have been different SPP guiding structures proposed such as metal nanoparticle chains, metal films, metal-insulator-metal (MIM) slabs, metal grooves, metal strips, and a hybrid Bragg waveguide, among which MIM slabs have attracted significant attention due to their suitability for highly-integrated photonic circuits and a good trade-off between the light confinement and energy loss [ 6 ]. Therefore, various devices based on MIM waveguides have been proposed, including switches [ 7 ], filters [ 8 , 9 , 10 ], sensors [ 11 , 12 ], splitters [ 13 ], and demultiplexer sensors [ 14 ].…”

A Metal-Insulator-Metal Deep Subwavelength Cavity Based on Cutoff Frequency Modulation

“…Recently, many researchers have investigated the miniaturization of photonic devices by using SPPs because of their ability to manipulate photons in subwavelength-sized cavities and waveguides beyond the diffraction limit, which is a fundamental size limit of dielectric photonic devices [2][3][4][5]. In particular, plasmon cavities are exploited in deep subwavelength volume lasers [4,6], switches [7,8], index sensors [9,10], and plasmonic optical filters [11][12][13].…”

High-Resolution Plasmonic Filter and Refractive Index Sensor Based on Perturbed Square Cavity with Slits and Orthogonal Feeding Scheme

“…One of the SPP guiding structures are metal-insulator-metal (MIM) slabs, which are very suitable for highly integrated photonic circuits and they offer a very good trade-off between light confinement and energy loss [4]. Therefore, various components based on MIM waveguides have been proposed including filters [5][6][7][8][9][10][11][12][13][14], splitters [15], demultiplexers [16], power dividers [17], and sensors [18][19][20][21][22][23][24][25][26].…”

“…When it comes to filters, which are of crucial importance in optical systems, there have been proposed different plasmonic configurations to achieve filtering operation, such as circular [12], square [8,11], and rectangular cavities [13], as well as stub [5], ring [6,9,10], spiral [7], and complementary split ring resonators [14]. However, most filters cannot simultaneously meet the requirements for a very accurate wavelength selection, low loss, and compactness.…”