Octave-spanning coherent supercontinuum generation in an AlGaAs-on-insulator waveguide

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nonlinear Optics

Background:

• Supercontinuum generation is crucial for various applications, including spectroscopy and optical communications.
• Aluminum gallium arsenide (AlGaAs) on insulator offers a highly nonlinear platform for integrated photonics.
• Achieving octave-spanning supercontinuua requires precise control over waveguide dispersion and nonlinear effects.

Purpose of the Study:

• To demonstrate octave-spanning supercontinuum generation on an AlGaAs-on-insulator platform.
• To investigate the role of dispersive waves in broadband light generation.
• To validate the coherence properties of the generated supercontinuum.

Main Methods:

• Fabrication of a 3-mm-long dispersion-engineered AlGaAs-on-insulator nano-waveguide.
• Pumping the waveguide with 3.6 pJ femtosecond pulses at telecom wavelengths (1555 nm).
• Experimental characterization of supercontinuum spectrum and coherence, supported by numerical simulations.

Main Results:

• Supercontinuum generation spanning from 1055 to 2155 nm (octave span).
• Observation of two distinct dispersive waves enabling the broadband generation.
• Experimental validation of coherence around the pump wavelength (1450-1750 nm).
• Numerical simulations indicating high coherence across the entire spectrum.

Conclusions:

• The AlGaAs-on-insulator platform is highly effective for octave-spanning supercontinuum generation.
• Dispersive wave generation is a key mechanism for achieving broadband spectra in such waveguides.
• The generated supercontinuum exhibits high coherence, making it suitable for advanced applications.