Development of Broadband Sources Based on Semiconductor Optical Amplifiers and Erbium-Doped Fiber Amplifiers for Optical Coherence Tomography

Broadband sources (BBSs) are commonly used in a wide range of applications in optical communication systems and biophotonics. They are particularly useful tools for biomedical imaging techniques such as optical coherence tomography (OCT). In order to obtain high image quality, we have developed a novel, low-cost, BBS based on semiconductor optical amplifiers combined with an erbium-doped fiber amplifier. It has bandwidth (BW) between 100 and 150 nm (ranging from 1450 to 1630 nm) and output power between 4 and 9 mW. Several configurations optimizing the BW, the spectral shape, and the output power are compared and tested in a time-domain OCT system. Images and OCT autocorrelation traces are compared for each configuration. The different sources provide an axial resolution of $\approx \hbox{10}\;\mu$m, with low sidelobes in the OCT autocorrelation function. Images realized with each configuration are compared with more expensive sources and systems such as Ti:sapphire lasers and spectral domain OCT system. It is shown that the optimized sources can have a global image aspect that is comparable with these systems.