Gamma radiation effects on silicon photonic waveguides

Area of Science:

• Integrated photonics
• Materials science
• Radiation effects

Background:

• Integrated photonics are crucial for space applications.
• Understanding radiation hardness is vital for device reliability in harsh environments like outer space.
• Previous studies on crystalline silicon showed limited radiation tolerance.

Purpose of the Study:

• To establish the radiation hardness threshold of silicon photonic waveguides.
• To investigate the impact of MeV-range gamma rays on amorphous silicon, silicon dioxide, and polymers used in photonic devices.
• To compare the radiation tolerance of amorphous silicon with crystalline silicon.

Main Methods:

• Irradiation of high-quality factor amorphous silicon core resonators with gamma (γ) rays.
• Measurement of material changes in amorphous silicon, silicon dioxide, and polymer components.
• Quantification of absorbed dose effects up to 15 Mrad.

Main Results:

• Amorphous silicon and silicon dioxide demonstrated robustness up to 15 Mrad absorbed dose.
• These materials showed over 100x greater radiation hardness compared to previous reports on crystalline silicon.
• Polymer materials exhibited significant changes at doses as low as 1 Mrad.

Conclusions:

• Amorphous silicon and silicon dioxide are suitable for integrated photonics in high-radiation environments.
• Polymers present a vulnerability in silicon photonic systems exposed to MeV-range gamma radiation.
• The findings support the development of radiation-hardened photonic devices for space exploration.