Cut-off-based dual-taper reflectors in on-chip hollow waveguides

Area of Science:

• Photonics and optical engineering
• Materials science

Background:

• Hollow Bragg waveguides offer unique light confinement properties.
• Developing efficient on-chip optical components is crucial for integrated photonics.

Purpose of the Study:

• To introduce novel dual tapers integrated into hollow Bragg waveguides.
• To demonstrate their functionality as waveguide filters and in-plane reflectors.

Main Methods:

• Fabrication of dual tapers using a thin film buckling approach.
• Integration within silicon/silicon dioxide-based omnidirectional Bragg waveguides.
• Characterization of optical transmission and reflection properties.

Main Results:

• The dual tapers exhibit a short-pass transmission characteristic due to mode cutoff.
• The upper pass-band edge is tunable by controlling the tunnel section height.
• Preliminary results show potential as in-plane reflectors for microcavities.

Conclusions:

• Dual tapers in hollow Bragg waveguides act as effective waveguide filters.
• This design enables the creation of novel open-access hollow-waveguide microcavities.