External Line-Cavity Wavelength-Swept Source at 850 nm for Optical Coherence Tomography

We constructed a novel and compact wavelength-swept laser source at the 850-nm region using an external line cavity in a modified Littman configuration filter. The angle alignment stability was improved by separating the function of output coupling and the wavelength selection of diffraction grating with gold coating. Our swept source produces laser output at the center wavelength of 849 nm and the average power of 2 mW with the full-width at half-maximum of 48 nm. The system performance is discussed and a two-dimensional image of a biological sample is presented