Integrated optical temporal Fourier transformer based on a chirped Bragg grating waveguide.

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Waveguide Technologies

Background:

• Integrated photonic devices are crucial for advanced optical signal processing.
• Temporal Fourier transformation is a key operation in manipulating optical signals.
• Existing methods for temporal Fourier transformation often lack integration or require complex setups.

Purpose of the Study:

• To experimentally demonstrate the first integrated temporal Fourier transformer.
• To utilize a linearly chirped Bragg grating waveguide for spectral-to-temporal mapping.
• To validate the device's functionality for both amplitude and phase manipulation of optical waveforms.

Main Methods:

• Fabrication of a silica glass waveguide with a femtosecond laser.
• Writing a linearly chirped Bragg grating within the waveguide.
• Utilizing first-order chromatic dispersion for spectral-to-temporal mapping.
• Experimental validation using temporal oscilloscope traces and Fourier transform spectral interferometry.

Main Results:

• Successful demonstration of an integrated temporal Fourier transformer.
• Operation in reflection with a 10 nm bandwidth.
• Capability to process temporal waveforms up to 20 ps.
• Accurate transformation of in-phase and out-of-phase optical pulse pairs.
• Validation of amplitude and phase control in the output temporal waveform.

Conclusions:

• The developed device represents a significant advancement in integrated photonic signal processing.
• The chirped Bragg grating waveguide offers a compact and efficient solution for temporal Fourier transformation.
• This technology has potential applications in optical communications, spectroscopy, and ultrafast signal processing.