A silicon-on-insulator substrate hosts a broadband wavelength filter featuring perturbed Bragg gratings. This perturbation is induced by strategically placing waveguides near the gratings. The use of smaller grating corrugation widths leads to a larger coupling coefficient, thereby significantly improving the grating reflectivity. Theoretical analysis of this compact device reveals a simplified circuit design, which is further corroborated by finite difference time domain simulation results. The achieved broadband filter boasts a bandwidth of approximately 40 nm, coupled with an impressive extinction ratio of around 39 dB, all achieved with a modest grating length of only . The rate of change of the Bragg wavelength concerning the width of the perturbed waveguide is approximately 0.0625. It is noteworthy that this achievement is attained by maintaining fixed waveguide and grating parameters while selectively altering the width of the perturbed waveguide. |
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Waveguides
Bragg wavelengths
Optical filters
Optical gratings
Bragg gratings
Tunable filters
Design