Flat spectral response silicon arrayed waveguide gratings via ion implantation.

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Flat spectral response is crucial for photonic networking applications.
• Existing technologies for achieving this can be costly.
• Silicon-on-insulator (SOI) platform offers a potential low-cost alternative.

Purpose of the Study:

• To demonstrate a novel method for achieving a flat spectral response in arrayed waveguide gratings (AWGs).
• To investigate the use of free carrier absorption via ion implantation as a cost-effective solution.
• To optimize AWG design for single-mode, birefringence-free operation.

Main Methods:

• Designed AWGs on a 1.5µm Si-overlayer SOI wafer with specific rib waveguide dimensions (1.1µm width, 0.88µm etch-depth).
• Utilized ion implantation of dopant species (n-type and p-type) to induce free carrier absorption.
• Employed multiple ion implantation steps to ensure uniform dopant concentration and avoid phase errors.

Main Results:

• Achieved a significantly broadened passband of 0.5nm.
• Demonstrated a 5-fold increase in passband broadening compared to a Gaussian peak.
• N-type dopants resulted in a notable reduction in the required doping length compared to p-type dopants.

Conclusions:

• Free carrier absorption through ion implantation is an effective method for achieving a flat spectral response in SOI AWGs.
• The developed technique offers a promising low-cost alternative for photonic networking.
• Optimization of doping strategy, particularly using n-type dopants, enhances efficiency and reduces device footprint.