Co-polymer clad design for high performance athermal photonic circuits

Area of Science:

• Materials Science
• Photonics
• Optical Engineering

Background:

• Silicon photonics demand passive athermal optical filters for efficient WDM transceivers.
• Existing solutions face challenges with thermal stability and performance in Si-CMOS architectures.
• Low power consumption and high bandwidth density are critical for future communication systems.

Purpose of the Study:

• To analyze silicon-polymer composite structures for thermal compensation in optical filters.
• To investigate the impact of copolymer composition on optical and thermal properties.
• To assess the suitability of these materials for athermal silicon photonic circuits.

Main Methods:

• Deposition of poly(perfluorodecyl acrylate) (pPFDA) and p(PFDA-co-DVB) using initiated chemical vapor deposition (iCVD).
• Analysis of material properties, including C-F bond density, density, refractive index, and volume expansion coefficient.
• Evaluation of thermo-optic (TO) coefficient and its effect on optical circuit performance.

Main Results:

• The addition of divinyl benzene (DVB) to pPFDA reduced C-F bond density and increased material density.
• Copolymerization with DVB increased refractive index and the volume expansion coefficient.
• The copolymer exhibited an increased thermo-optic (TO) coefficient, improving optical performance metrics.

Conclusions:

• Silicon-polymer composites, specifically p(PFDA-co-DVB), show promise for thermal compensation in optical filters.
• The modified material properties enhance bend loss, footprint, and Free Spectral Range (FSR) performance.
• These findings contribute to the development of advanced athermal silicon photonic circuits for next-generation communication.