Optical performance of hybrid metal‐insulator‐metal plasmonic waveguide for low‐loss and efficient photonic integration

Abstract

The fundamental mode characteristics of hybrid metal‐insulator‐metal plasmonic waveguide (HMIMPW), consists of a high‐index layer sandwiched between two spacer/low‐index and metal layers, has been explored to achieve relatively high power density with smaller effective mode area in low‐index waveguide region at the wavelength of 1550 nm. The HMIMPW has the advantage of low power loss with relatively large propagation distance, of order of several tens of λ. The simulation results have demonstrated that with spacer thickness of 10 nm, significantly higher confinement of optical mode power (> 65%) can be realized in the spacer region of HMIMPW with relatively smaller effective area of 0.0060 μm2 together with the power density > 200 μm−2. This type of analysis and results are very desirable for several specific applications, like optical sensing, nonlinear optics, optical manipulations. Further, the investigations on crosstalk performance between two parallel HMIMPWs have been addressed in order to realize the high integration density over the photonic chip. The decoupling separation of nearly 560 nm has been accomplished with the thicknesses of low‐ and high‐index regions, respectively, of 10 and 50 nm.

Design of Nanoscale Hybrid Insulator-Metal-Insulator Plasmonic Waveguide

“…To analyze the crosstalk between two HPWs, the coupling length has to be determined, as provided in Eq. (4) [14,16]. For the minimum/negligible crosstalk between the two HPWs, the coupling length must be significantly larger [37].…”

“…It essentially provides a common platform to interconnect the electronics and photonics devices. To achieve ultra-small waveguide dimension, various hybrid plasmonic waveguides (HPWs) have been proposed in literature, such as hybrid metal-insulator-metal [14][15][16][17], hybrid dielectric loaded plasmonic structure [18][19][20], hybrid metal cap plasmonic waveguide [21], hybrid insulator-metal-insulator [22,23], etc. Out of these possible structures of HPWs, the HIMIPW offers the least propagation loss with tight light confinement at true nano-scale regions.…”

Reduction in Crosstalk Using Uniform Germanium Strips for Dense Integration of Photonic Waveguides

“…However, by keeping a sufficient separation between the adjacent waveguides, the extent of power transfer can be reduced, and it can act as an individual waveguide. The coupling length ( ) can be described as a length over which the optical power is fully transferred from one waveguide to the adjacent waveguide, and it can be expressed as [15],…”

“…The propagation length is highly reliant on the imaginary part of the effective refractive index, i.e., ( ), of the guided mode. It can be defined as a length of waveguide over which the propagating power drops to 1/e of its total power, and can be expressed as [15],…”

“…Therefore, the investigations on crosstalk performance between the two adjacent photonic waveguides, is essentially required to achieve the high photonic integration in the photonic chip. The crosstalk between two adjacent photonic waveguides can be estimated as [15][16], ( ) = 10 10 [sin ( 0…”