Bandwidth and wavelength-tunable optical bandpass filter based on silicon microring-MZI structure

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Optical filters are crucial components in wavelength-division multiplexing (WDM) systems.
• Existing tunable filters often face limitations in performance, tunability, or complexity.
• Silicon photonics offers a scalable platform for integrated optical devices.

Purpose of the Study:

• To propose and demonstrate a novel, simple, and tunable optical bandpass filter.
• To achieve simultaneous bandwidth and wavelength tunability.
• To optimize filter performance metrics like shape factor and extinction ratio.

Main Methods:

• Design and fabrication of a Mach-Zehnder interferometer (MZI) structure incorporating two silicon microring resonators.
• Utilizing the drop transmissions of microring resonators for filter functionality.
• Employing thermal control to tune the phase difference in the MZI arms and the resonance offset between microrings.

Main Results:

• Demonstration of a bandwidth and wavelength-tunable optical bandpass filter.
• Successful optimization of shape factor and extinction ratio through thermal control.
• Achieved simultaneous tunability with in-band ripple control via resonance offset tuning.

Conclusions:

• The proposed silicon microring-based MZI filter offers a simple and effective solution for tunable optical filtering.
• The demonstrated thermal tuning mechanism provides precise control over filter bandwidth, wavelength, and in-band ripple.
• This technology holds promise for advanced optical communication and signal processing applications.