Linear-in-wavenumber actively-mode-locked wavelength-swept laser

Area of Science:

• Photonics and Optical Engineering
• Biomedical Imaging Technology
• Laser Physics

Background:

• Wavelength-swept lasers (ASLs) are crucial for optical coherence tomography (OCT).
• Achieving highly linear wavenumber sweeps is challenging but essential for accurate frequency-domain ranging.
• Existing ASLs often require data resampling, complicating OCT system design.

Purpose of the Study:

• To develop an akinetic actively-mode-locked wavelength-swept laser (ASL) with a highly linear wavenumber sweep.
• To enable high-fidelity frequency-domain interferometric ranging without data resampling.
• To evaluate the ASL's performance for catheter-based optical coherence tomography.

Main Methods:

• Designed an akinetic actively-mode-locked laser architecture.
• Tailored the drive waveform of the intracavity modulator to linearize the wavenumber sweep.
• Integrated the ASL into a catheter-based optical coherence tomography system.
• Compared imaging performance against a state-of-the-art polygon-based wavelength-swept source.

Main Results:

• Achieved a highly linear wavenumber sweep by optimizing the drive waveform.
• Enabled high-fidelity frequency-domain interferometric ranging without data resampling.
• Demonstrated comparable imaging performance to a polygon-based ASL at 103.6 kHz sweep rate, 95% duty cycle, and 100 nm bandwidth (1330 nm center).

Conclusions:

• The developed ASL offers a viable alternative to polygon-based sources for OCT.
• Linearized wavenumber sweeps simplify OCT data processing by eliminating resampling needs.
• This technology advances catheter-based OCT imaging capabilities.