In this work, we use inverse imaging for object reconstruction from nonuniformly-spaced samples in Fourier
domain optical coherence tomography (FD-OCT). We first model the FD-OCT system with a linear system of
equations, where the source power spectrum and the nonuniformly-spaced sample positions are represented accurately.
Then, we reconstruct the object signal directly from the nonuniformly-spaced wavelength measurements.
With the inverse imaging method, we directly estimate the 2D cross-sectional object image instead of a set of
independent A-line signals. By using the Total Variation (TV) as a constraint in the optimization process, we
reduce the noise in the 2D object estimation. Besides TV, object sparsity is also used as a regularization for
the signal reconstruction in FD-OCT. Experimental results demonstrate the advantages of our method, as we
compare it with other methods.
We report a 45 kHz spectroscopic OCT system based on a swept laser source utilizing two wavelength bands.
The source is generated by single-band swept laser input and a fiber optical parametric amplifier. The time-multiplexing
architecture reduces the complexity of the coupling and detecting configuration in comparison with
the previous dual-band swept-source setup. This high-speed spectroscopic OCT combines the advantages of the
speed of the swept laser and contrast enhancement, in comparison with the time or spectral-domain spectroscopic
OCT system. In the experiment, spectroscopic OCT imaging around 1550 nm is achieved for the first time. The
difference in images at 1500 nm and 1600 nm clearly shows different back scattering and penetration properties
which can be used for tissue classification and water content measurement.
High repetition rate pulsed fiber laser in 1μm is an attractive and novel source for optical transmission systems, since
ytterbium-doped fiber (YDF) has the potential to provide broad gain spectrum and high optical conversion efficiency in
this regime. Previous works in this area have explored the wavelength range above 1050 nm. In this paper, we focus
more on the shorter wavelength band which is closer to the peak of the emission cross section of YDF at around 1030 nm.
A 10-GHz harmonically mode-locked all-fiber laser is demonstrated. A pulse train with a pulsewidth of around 13 ps and
wavelength tunable from 1023.5 nm to 1053.3 nm is achieved. The
side-mode suppression ratio is more than 50 dB
without any stabilization techniques.