title: Extended bandwidth wavelength swept laser source for high resolution optical frequency domain imaging.
abstract: Improving the axial resolution by providing wider bandwidth wavelength swept lasers remains an important issue for optical frequency domain imaging (OFDI). Here, we demonstrate a wide tuning range, all-fiber wavelength swept laser at a center wavelength of 1250 nm by combining two ring cavities that share a single Fabry-Perot tunable filter. The two cavities contain semiconductor optical amplifiers with central wavelengths of 1190 nm and 1292 nm, respectively. To avoid disturbing interference effects in the overlapping spectral region, we modulated the amplifiers in order to obtain consecutive wavelength sweeps in the two spectral regions. The two sweeps were fused together in post-processing to achieve a total scanning range of 223 nm, corresponding to 3.3 µm axial resolution in air. We confirm improved image quality and reduced speckle size in tomograms of swine esophagus ex vivo, and human skin and nailbed in vivo.
authors.forename: Sahar Hosseinzadeh
authors.initials: SH
authors.lastname: Kassani
authors.forename: Martin
authors.initials: M
authors.lastname: Villiger
authors.forename: Néstor
authors.initials: N
authors.lastname: Uribe-Patarroyo
authors.forename: Changsu
authors.initials: C
authors.lastname: Jun
authors.forename: Reza
authors.initials: R
authors.lastname: Khazaeinezhad
authors.forename: Norman
authors.initials: N
authors.lastname: Lippok
authors.forename: Brett E
authors.initials: BE
authors.lastname: Bouma
mesh_terms: D000465:Algorithms; D000669:Amplifiers, Electronic; D000818:Animals; D004947:Esophagus / Q000000981:diagnostic imaging; D005336:Fiber Optic Technology / Q000295:instrumentation; D005583:Fourier Analysis; D006801:Humans; D007834:Lasers; D061848:Optical Imaging / Q000379:methods*; D012666:Semiconductors; D012867:Skin / Q000000981:diagnostic imaging; D013552:Swine; D041623:Tomography, Optical Coherence / Q000379:methods