Design of two-dimensional sampled Bragg grating for a curved waveguide.

Area of Science:

• Photonics
• Integrated Optics
• Waveguide Technology

Background:

• Curved waveguide gratings (CWG) are crucial for altering light paths in photonic integrated circuits.
• Fabricating CWGs with precise control over light propagation direction remains challenging.

Purpose of the Study:

• To propose and demonstrate a novel cascaded sampled Bragg grating on tilted waveguide (CSBG-TW) structure.
• To achieve the functional equivalent of CWGs using a more controllable and manufacturable approach.

Main Methods:

• Designing two-dimensional (2D) sampled gratings to control sub-grating vector direction.
• Dividing a curved waveguide into multiple sections of tilted waveguides.
• Maintaining grating direction parallel to the local waveguide longitudinal direction.

Main Results:

• The CSBG-TW structure effectively mimics CWG functionality.
• Reflection intensity differences between CSBG-TW and target CWG are less than 0.1 dB.
• Micro-scale sampling structures enable accurate wavelength control.

Conclusions:

• CSBG-TW offers a viable alternative to traditional CWGs for photonic integrated circuits.
• The proposed structure simplifies fabrication via holographic exposure.
• CSBG-TW is suitable for devices requiring dynamic light path manipulation.