Design and simulation of apodized wavelength filters using Gaussian-distributed sidewall grating

Abstract

An accurate design for an apodized integrated optical wavelength filter using Gaussian-distributed sidewall Bragg grating is proposed, 2-dimensionally simulated and analyzed using the finite-difference time-domain method. It is verified that for various grating periods, the central wavelengths of the reflection bands are all fixed at designed 1.55 µm with the side lobes well suppressed.

Investigations into the design and fabrication of silicon photonic broadband wavelength selective switches and filters

“…5-2. The Bragg gratings on the side wall of a waveguide is easy to fabricate in a single lithographic step and the effective refractive index of the grating which is dependent on the lateral waveguide widths can be easily controlled in the lithographic step [160,161]. Since the gratings can be applied on a strip waveguide, it is easy to satisfy the single mode propagation in these waveguide gratings.…”

“…This condition is known as the Bragg condition and the reflected wavelength is known as the Bragg wavelength, λ B . to achieve improved filter response from the gratings [160,161]. Inverse of the K, defined as Bragg length L B is an interesting parameter for the gratings which gives the length of the gratings for 100% reflectivity.…”