Small core rib waveguides with embedded gratings in As2Se3 glass

Area of Science:

• Materials Science
• Optoelectronics
• Photonics

Background:

• Chalcogenide glasses, such as As2Se3, are promising materials for optical applications due to their unique optical properties.
• Developing low-loss waveguides is crucial for integrated photonic devices.
• Shallow-rib waveguide structures offer advantages in light confinement and mode control.

Purpose of the Study:

• To fabricate low-loss shallow-rib waveguides using As2Se3 chalcogenide glass and polyamide-imide polymer.
• To characterize the optical properties of the fabricated waveguides, including modal effective area and propagation losses.
• To investigate the potential of these waveguides for all-optical Kerr effect devices by incorporating Bragg gratings.

Main Methods:

• Waveguide fabrication through photodarkening of As2Se3 followed by selective wet etching.
• Near-field modal measurements to determine the modal effective area.
• Fabry-Perot technique to estimate propagation losses.
• Holographic patterning of first-order Bragg gratings near 1550 nm.

Main Results:

• Fabrication of low-loss shallow-rib waveguides with As2Se3 and polyamide-imide polymer.
• Modal effective area measurements consistent with theoretical predictions (3.5-4 microm2).
• Estimated propagation losses as low as approximately 0.25 dB/cm.
• Successful patterning of Bragg gratings with an index modulation of ~0.004, used to assess modal effective indices.

Conclusions:

• The fabricated As2Se3 shallow-rib waveguides exhibit low propagation losses, making them suitable for photonic applications.
• Embedded Bragg gratings in these waveguides can be used for effective index assessment.
• These small core As2Se3 waveguides with Bragg gratings hold significant potential for the development of all-optical Kerr effect devices.