Changho Chong

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A two- and three-dimensional swept source optical coherence tomography (SS-OCT) system, which uses a ready-to-ship scanning light source, is demonstrated. The light source has a center wavelength of 1.31 mum, -3 dB wavelength range of 110 nm, scanning rate of 20 KHz, and high linearity in frequency scanning. This paper presents a simple calibration method(More)
This paper presents a novel configuration of a MEMS scanning endoscope that is actuated by external optical modulation. Light at a wavelength in the 1550nm range is used to modulate a scanning MEMS mirror, and wavelength of 1310nm, commonly used for optical coherence tomography (OCT), is used for the probe beam. This novel approach provides for the(More)
We present and demonstrate a swept source with a large coherence length using a quasi-phase continuous tuning (QPCT) technique. QPCT is a method of minimizing the phase shift per round trip with respect to the tunable filter so that the resonance of lasing becomes high, resulting in high finesse of lasing during a rapid sweep. The demonstrated swept source(More)
The transition from benchtop to clinical system often requires the medical technology to be robust, portable and accurate. This poses a challenge to current swept source optical coherence tomography imaging systems, as the bulk of the systems footprint is due to laser components. With the recent advancement of micromachining technology, we demonstrate the(More)
This paper reports on a technique to improve the coherence length of a high-speed wavelength swept laser. The wavelength swept laser comprises a pigtailed semiconductor optical amplifier and a wavelength-scanning filter in a fiber extended cavity configuration. The laser operates in the 1310 nm wavelength region. The tunable filter consists of a diffraction(More)
A new processing technique called non-harmonic analysis (NHA) is proposed for optical coherence tomography (OCT) imaging. Conventional Fourier-domain OCT employs the discrete Fourier transform (DFT), which depends on the window function and length. Its axial resolution is inversely proportional to the DFT frame length. The DFT frame length is limited by the(More)
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