This is the first report on 3D sinusoidal Bragg grating structure based on hybrid metal insulator metal (HMIM) plasmonic waveguide. The proposed structure has a gradual change in the refractive index rather than an abrupt change providing excellent filtering characteristics. The device is studied at an operating wavelength of 1.55 μm. The results are based on numerical simulations performed using the software CST microwave studio suite. The transmission characteristics show more than 80% transmission in the passband and near zero transmission in the rejection band. The proposed structure reduces the scattering losses and a wide bandgap of 0.387 μm is achieved. The proposed structure has a track length of 3.784 μm for 11 cells, which is very less compared to previous reports allowing large-scale integration of photonic devices. A microcavity is also formed and its resonance is investigated by introducing a defect length of 0.217 μm in the periodic structure. A peak transmission of 50% and a narrow resonance bandwidth of 0.029 μm are achieved at 1.55 μm resonance wavelength. The quality factor which defines the energy stored in the cavity is Q = 53.

The design of integrated components using hybrid plasmonics is attracting a widespread interest in the recent years. This work proposes a consistent approach to design Bragg gratings employing the concept of graded profile in a planar hybrid metal–insulator–metal plasmonic waveguide. A comparative study of various width modulations such as triangular, parabolic and rectangular profiles is presented. The most striking observation is that Bragg gratings with parabolic profile offer best performance in terms of compact track length (3.48 μm), wide stopband (168 nm) and good transmission characteristics with fewer side lobes. Additionally, a nanocavity analysis is performed by introducing a defect length of 140 nm in the Bragg grating structure with parabolic profile. A peak transmission of 89% is observed at the resonance wavelength of 1550 nm.