"K-space linear Fourier domain mode locked laser and applications for optical coherence tomography"Christoph M. Eigenwillig, Benjamin R. Biedermann, Gesa Palte, and Robert Huber
Optics Express 16, 8916 (2008)
We report on a Fourier Domain Mode Locked (FDML) wavelength swept laser source with a highly linear time-frequency sweep characteristic and
demonstrate OCT imaging without k-space resampling prior to Fourier transformation. A detailed theoretical framework is provided and different
strategies how to determine the optimum drive waveform of the piezo-electrically actuated optical bandpass-filter in the FDML laser are discussed.
An FDML laser with a relative optical frequency deviation Δν/ν smaller than 8⋅10-5 over a 100 nm spectral bandwidth at 1300 nm is presented, enabling high resolution OCT over long ranging depths. Without numerical
time-to-frequency resampling and without spectral apodization a sensitivity roll off of 4 dB over 2 mm, 12.5 dB over 4 mm and 26.5 dB over 1 cm at
3.5 µs sweep duration and 106.6 dB maximum sensitivity at 9.2 mW average power is achieved. The axial resolution in air degrades from 14 to
21 µm over 4 mm imaging depth. The compensation of unbalanced dispersion in the OCT sample arm by an adapted tuning characteristic of the source is demonstrated. Good stability of the system without feedback-control loops is observed over hours.
BMO authors (in alphabetic order):
Optical Coherent Ranging and Optical Coherence Tomography (OCT): Imaging and profilometry with rapidly frequency swept laser sources
Fourier Domain Mode Locking (FDML): Spectral mode locking in optics and applications