Optical autocorrelator that uses a surface-emitting second-harmonic generator on (211)B GaAs

Area of Science:

• Optoelectronics
• Materials Science
• Nonlinear Optics

Background:

• Optical autocorrelators are crucial for measuring ultrashort optical pulses.
• Existing designs on (100) Gallium Arsenide (GaAs) substrates face challenges with transverse electric (TE) and transverse magnetic (TM) mode interference.
• Alternative substrate orientations are needed to improve device performance and simplify operation.

Purpose of the Study:

• To demonstrate a novel optical autocorrelator utilizing surface-emitted second-harmonic generation (SE-SHG).
• To investigate the performance of SE-SHG on a (211)B GaAs substrate.
• To evaluate the advantages of the (211)B orientation for optical device applications.

Main Methods:

• Fabrication of an optical autocorrelator on a (211)B GaAs substrate.
• Utilizing visible surface-emitted second-harmonic generation for device operation.
• Employing transverse electric (TE) mode excitation exclusively.

Main Results:

• Successful demonstration of an optical autocorrelator on a (211)B GaAs substrate.
• The (211)B orientation requires only TE mode excitation, eliminating TE/TM mode beating.
• Achieved higher upconversion efficiency compared to (111) growth and obtained waveguide loss and effective refractive index differences.

Conclusions:

• The (211)B GaAs substrate is a promising orientation for advanced optical autocorrelators.
• This approach simplifies device operation by eliminating mode-beating issues.
• The demonstrated device offers enhanced upconversion efficiency and provides valuable optical parameter data.