CMOS-compatible temperature-independent tunable silicon optical lattice filters

Area of Science:

• Integrated photonics
• Silicon photonics
• Optical filter technology

Background:

• Athermal optical filters are essential for stable performance in varying temperatures.
• Silicon photonics offers a platform for miniaturized and power-efficient optical devices.
• Mach-Zehnder interferometers are fundamental components in optical filtering and signal processing.

Purpose of the Study:

• To develop and characterize a CMOS-compatible athermal tunable silicon optical lattice filter.
• To investigate the active tuning capabilities and power consumption of the filter.
• To analyze the thermal-sensitivity of the filter before and after wavelength tuning.

Main Methods:

• Fabrication of a 10-stage cascaded asymmetric Mach-Zehnder interferometer silicon optical lattice filter.
• Active tuning experiments to measure central wavelength shifts and power consumption.
• Temperature shift measurements to quantify thermal-sensitivity.
• Theoretical modeling using the transfer matrix method.

Main Results:

• The filter demonstrated active tuning with red-shifts up to 13.1 nm and blue-shifts up to 21.3 nm.
• Power consumption for tuning was measured at 77 mW (top arm) and 96 mW (bottom arm).
• The filter exhibited a low initial thermal-sensitivity of -1.465 pm/°C.
• Tuning the central wavelength altered the thermal-sensitivity within the range of 26.5 pm/°C to -27.1 pm/°C.

Conclusions:

• The developed silicon optical lattice filter is CMOS-compatible and offers effective athermal and tunable operation.
• Active tuning provides precise control over the central wavelength with moderate power consumption.
• The filter's thermal-sensitivity can be managed during active tuning, ensuring stable performance across different operating conditions.