Photothermally tunable silicon-microring-based optical add-drop filter through integrated light absorber

Area of Science:

• Photonics
• Materials Science
• Nanotechnology

Background:

• Thermo-optic (TO) devices are crucial for optical signal processing.
• Existing TO devices often have slow response times or require electrical control.
• Integrated silicon photonics demands efficient and fast optical switching solutions.

Purpose of the Study:

• To demonstrate an optically pumped thermo-optic (TO) silicon ring add-drop filter with a fast thermal response.
• To integrate a metal-insulator-metal (MIM) light absorber as a localized heat source for TO silicon devices.
• To investigate the potential of this approach for all-optical routing and switching.

Main Methods:

• Fabrication of a silicon ring add-drop filter integrated with a MIM light absorber.
• Optical pumping of the MIM absorber to induce a thermo-optic effect.
• Experimental characterization of the device's optical response time and wavelength shift with pump power.

Main Results:

• Experimental demonstration of an optically pumped TO silicon ring add-drop filter.
• Achieved a fast optical response time of 13.7 μs (10%-90% rule).
• Measured a wavelength shift of 60 pm/mW, indicating efficient photothermal tuning.

Conclusions:

• The MIM absorber integration provides a localized, low-thermal-capacity heat source for TO silicon devices.
• The photothermally tunable add-drop filter exhibits a fast response, suitable for optical routing.
• This approach offers new possibilities for all-optical routing and switching in integrated silicon photonic circuits.