title: Extended coherence length Fourier domain mode locked lasers at 1310 nm.
abstract: Fourier domain mode locked (FDML) lasers are excellent tunable laser sources for frequency domain optical coherence tomography (FD-OCT) systems due to their combination of high sweep rates, large tuning ranges, and high output powers. However, conventional FDML lasers provide coherence lengths of only 4-10 mm, limiting their use in demanding applications such as intravascular OCT where coherence lengths of >20 mm are required for optimal imaging of large blood vessels. Furthermore, like most swept lasers, conventional FDML lasers produce only one useable sweep direction per tunable filter drive cycle, halving the effective sweep rate of the laser compared to the filter drive frequency. Here, we demonstrate a new class of FDML laser incorporating broadband dispersion compensation near 1310 nm. Elimination of chromatic dispersion in the FDML cavity results in the generation of forward (short to long wavelength) and backward (long to short wavelength) sweeps with substantially identical properties and coherence lengths of >21 mm. This advance enables long-range, high-speed FD-OCT imaging without the need for optical buffering stages, significantly reducing laser cost and complexity.
authors: LightLab Imaging Inc., a St. Jude Medical subsidiary, 1 Technology Park Drive, Westford, MA 01886, USA. DAdler@sjm.com
authors: Desmond C
authors: DC
authors: Adler
authors: Wolfgang
authors: W
authors: Wieser
authors: Francois
authors: F
authors: Trepanier
authors: Joseph M
authors: JM
authors: Schmitt
authors: Robert A
authors: RA
authors: Huber
mesh_terms: D000465:Algorithms; D001709:Biotechnology / Q000379:methods; D003952:Diagnostic Imaging / Q000379:methods; D004867:Equipment Design; D005583:Fourier Analysis; D007834:Lasers; D015233:Models, Statistical; D055100:Optical Fibers; D055095:Optics and Photonics / Q000379:methods*; D012666:Semiconductors; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*