Mach-Zehnder crossbar switching and tunable filtering using N-coupled waveguide Bragg resonators

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Semiconductor Devices

Background:

• Silicon-on-insulator (SOI) platform is crucial for integrated photonic circuits.
• Mach-Zehnder interferometers (MZIs) are fundamental components for optical switching and filtering.
• Thermo-optical (TO) actuation offers a viable method for tuning photonic devices.

Purpose of the Study:

• To design and simulate novel 1500-nm SOI 2x2 MZI optical crossbar switches and tunable filters.
• To evaluate the performance metrics of these devices, focusing on insertion loss (IL) and crosstalk (CT).
• To explore the potential of composite filter profiles using series-connected MZIs.

Main Methods:

• Theoretical modeling and simulation using a mixed full-vectorial mathematical model.
• Finite-element, coupled-mode, and transfer-matrix approaches were employed for accurate design.
• Butterworth-filter technique was utilized for grating length and weighting optimization.

Main Results:

• The proposed MZI devices exhibit a better-than-Lorentzian spectral shape with steeper sidewalls.
• Predicted insertion loss (IL) and crosstalk (CT) values are superior to existing MZI devices in the literature.
• Tunable composite filter profiles with a tuning range of approximately 2 nm were demonstrated.

Conclusions:

• The developed thermo-optical MZI designs show promise for high-performance optical switching and filtering applications.
• The proposed devices offer significant advantages in terms of IL and CT over current technologies.
• Series arrangements of MZIs enable the creation of versatile tunable filter profiles.