Accurate photonic waveguide characterization using an arrayed waveguide structure.

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Engineering

Background:

• Reducing waveguide loss is key for advanced photonic integrated circuits.
• Traditional loss measurement methods suffer from significant uncertainties due to unknown environmental parameters like facet reflectivity and coupling efficiency.

Purpose of the Study:

• To develop a novel, highly accurate loss measurement technique for photonic waveguides.
• To overcome the limitations of conventional methods by minimizing dependence on external factors.

Main Methods:

• Utilizing an arrayed waveguide structure to measure differential loss between multiple paths.
• Employing a swept-wavelength interferometer to analyze waveguide transmission as a function of group delay.
• Extracting propagation loss based solely on the differential path length between waveguides.

Main Results:

• The novel technique accurately characterizes waveguide loss independently of on- and off-chip coupling efficiencies.
• Statistics on propagation loss are gathered from several waveguides in a single measurement.
• The method achieved a low uncertainty of less than 0.06 dB/cm for silicon photonic waveguides.

Conclusions:

• The differential loss measurement technique offers a reliable and accurate approach for characterizing photonic waveguide loss.
• This method is essential for advancing fabrication technologies and enabling next-generation photonic devices.
• The technique's independence from coupling efficiencies significantly enhances measurement precision.