1.3 µm High‐Coherence Supercontinuum Time‐Stretched Swept Source for Shot‐Noise‐Limited Long‐Range Optical Coherence Tomography

ABSTRACT

The 1.3 µm swept source optical coherence tomography (SS‐OCT) offers an ideal balance between scattering and absorption with deep tissue imaging. Limited by the gain medium, highly coherent and broadband swept laser working at 1.3 um is still a challenge. In this paper, we propose a highly coherent broadband supercontinuum with a 280 nm bandwidth and −130 dB/Hz relative intensity noise assisted by a section of anomalous dispersion highly nonlinear fiber, which is then used to achieve highly coherent time stretched swept laser with 14.1 MHz. The average cross‐correlation coefficient among different scanning cycles is 0.9975 and the coefficient of variation is as low as 0.013%, indicating that the swept laser exhibits excellent repeatability and stability. This proposed swept source is further applied in the SS‐OCT system, which achieves 7.5 µm axial resolution, 81.2 dB sensitivity, and a 6 dB sensitivity roll‐off imaging range of 58.5 mm. To the best of our knowledge, this is the first demonstration of a 1.3 µm SS‐OCT system based on a highly coherent broadband swept source that achieves shot‐noise‐limited sensitivity, which contributes to the applications of SS‐OCT system in both medical and industrial detection.