Silicon on ultra-low-loss waveguide photonic integration platform

Area of Science:

• Photonics and Materials Science
• Integrated Optics

Background:

• Silicon photonics offers high integration density but suffers from propagation losses.
• Silicon nitride waveguides provide ultra-low loss but are challenging to integrate with silicon.
• Efficient coupling between different waveguide materials is crucial for advanced photonic integrated circuits.

Purpose of the Study:

• To demonstrate a novel integrated platform combining silicon and ultra-low-loss silicon nitride (Si3N4) waveguides.
• To characterize the coupling efficiency and bandwidth between the silicon and Si3N4 layers.
• To measure the propagation loss of the ultra-low-loss Si3N4 waveguides.

Main Methods:

• Fabrication of a hybrid silicon and Si3N4 waveguide platform.
• Design and implementation of tapered couplers for inter-layer coupling.
• Optical characterization including loss and bandwidth measurements at 1590 nm wavelength.

Main Results:

• Achieved coupling losses of (0.4 ± 0.2) dB and (0.8 ± 0.2) dB per transition for two different tapered coupler designs.
• Demonstrated 3-dB bandwidths of 20 nm and 100 nm for the respective coupler designs.
• Measured a minimum propagation loss of 1.2 dB/m in the ultra-low-loss Si3N4 waveguides at 1590 nm.

Conclusions:

• The integrated silicon and Si3N4 platform enables efficient coupling between materials with distinct optical properties.
• The demonstrated low coupling loss and ultra-low propagation loss are promising for advanced photonic integrated circuits.
• This hybrid platform opens new avenues for high-performance optical devices and systems.