Silicon nitride/titanium oxide hybrid waveguide design enabling broadband athermal operation

Area of Science:

• Photonics and Materials Science
• Integrated Optics
• Waveguide Technology

Background:

• Conventional silicon nitride waveguides suffer from thermal drift due to their positive thermo-optic coefficient (TOC).
• Maintaining stable optical performance across varying temperatures is crucial for applications like optical frequency comb generation.

Purpose of the Study:

• To design and analyze a novel silicon nitride/titanium oxide hybrid waveguide with broadband athermal operation.
• To achieve zero effective TOC and minimize thermal sensitivity for enhanced optical device performance.

Main Methods:

• Incorporation of multi-layer titanium oxide with a negative TOC into the waveguide core and cladding.
• Numerical demonstration of temperature change effects on optical frequency comb generation in both traditional and hybrid waveguides.

Main Results:

• The hybrid waveguide achieves a near-zero effective TOC (±6×10⁻⁷/K) across a broad wavelength band (1350–1850 nm).
• The athermal hybrid waveguide exhibits significantly reduced temperature sensitivity compared to traditional strip waveguides.
• The multi-layer laminate structure offers potential for fabricating thick, crack-free silicon nitride films for anomalous dispersion waveguides.

Conclusions:

• The developed silicon nitride/titanium oxide hybrid waveguide enables broadband athermal operation.
• This athermal design significantly improves the temperature stability of optical frequency comb generation.
• The multi-layer structure presents a promising approach for advanced waveguide fabrication and applications.