Mode imaging and loss evaluation of semiconductor waveguides

Area of Science:

• Optoelectronics
• Semiconductor device physics
• Photonics

Background:

• Semiconductor waveguides are essential components in integrated photonics.
• Accurate characterization of waveguide modes and losses is critical for device performance.
• Non-doped quantum wells offer a unique internal light source for probing waveguide properties.

Purpose of the Study:

• To develop and validate an imaging and loss evaluation method for semiconductor waveguides.
• To utilize the internal emission of non-doped quantum wells as a probe light source.
• To quantify the quality of single-mode semiconductor waveguides.

Main Methods:

• Charged-Coupled Device (CCD) imaging was employed to evaluate waveguide mode numbers and widths.
• The effective index method was used for theoretical validation of imaging results.
• Analysis of Fabry-Pérot fringes in waveguide emission spectra determined internal losses.

Main Results:

• Waveguide mode characteristics obtained via imaging aligned with effective index method calculations.
• Internal waveguide losses were successfully derived from spectral fringe analysis.
• The quality of 29 single-mode waveguide samples was quantified with an average internal loss of 10.2 ± 0.6 cm⁻¹.

Conclusions:

• The presented method provides an effective approach for evaluating semiconductor waveguide performance.
• Internal quantum well emission is a viable probe for non-destructive waveguide characterization.
• This technique enables precise quantification of waveguide quality for fabrication optimization.