Silicon optical filters reconfigured from a 16 × 16 Benes switch matrix

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Signal Processing

Background:

• Reconfigurable optical filters are crucial for adaptive signal processing.
• Existing filters often lack flexibility in performance tuning.

Purpose of the Study:

• To demonstrate infinite impulse response (IIR) silicon optical filters with variable filter orders.
• To utilize a Benes switch chip for reconfigurable optical filtering.

Main Methods:

• Employing dual-ring assisted Mach-Zehnder interferometers as the basic filter unit.
• Integrating TiN microheaters for precise control of ring resonator resonance.
• Reconfiguring optical paths within a 16x16 Benes switch chip to achieve different filter orders.

Main Results:

• Successfully obtained high-order optical filters ranging from 2nd to 14th order.
• Achieved a filter bandwidth tuning range from 0.19 nm to 1.06 nm with minimal in-band ripple.
• Demonstrated out-of-band rejection ratios exceeding 30 dB for 8th and 10th-order filters.

Conclusions:

• The proposed method allows flexible construction of wavelength-filtering devices by repurposing switch matrix architecture.
• This demonstrates a novel approach for creating tailorable optical filters for advanced signal processing applications.