Multi-wavelength filters in silicon using superposition sidewall Bragg grating devices.

Area of Science:

• Photonics and optical engineering
• Integrated optics
• Semiconductor devices

Background:

• Bragg gratings are widely used for optical filtering.
• Fabricating multiple, independently controlled filters often requires complex, lengthy devices.
• Achieving non-uniformly spaced stopbands presents a design challenge.

Purpose of the Study:

• To demonstrate a novel silicon Bragg grating device for realizing multiple, potentially non-uniformly spaced filter stopbands.
• To show that integrated filters can be significantly shorter than serial equivalents.
• To highlight the design flexibility of complex Bragg gratings.

Main Methods:

• Utilizing a superposition of sidewall relief grating functions.
• Fabricating individual filter responses within a single integrated device.
• Employing an eight-bit pseudorandom number generator to select filter combinations.

Main Results:

• Successfully realized multiple filter stopbands in a single integrated Bragg grating.
• Demonstrated that the integrated device length is N× shorter than serial gratings.
• Showcased arbitrary combinations of eight-basis filter responses.

Conclusions:

• The integrated Bragg grating device offers an efficient method for creating complex optical filter functionalities.
• This approach provides significant device length reduction for multiple optical filters.
• The demonstrated flexibility enables versatile applications in optical signal processing.