Open AccessDouble-clad fiber coupler for partially coherent detection
Author(s) -
Étienne De Montigny,
WendyJulie Madore,
Olivier Ouellette,
Gabriel Bernard,
M Leduc,
Mathias Strupler,
Caroline Boudoux,
Nicolas Godbout
Publication year - 2015
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.009040
Subject(s) - optics , cladding (metalworking) , materials science , tapering , confocal , microscope , optical sectioning , fabrication , confocal microscopy , optical fiber , speckle pattern , optoelectronics , computer science , physics , medicine , computer graphics (images) , alternative medicine , pathology , metallurgy
Double-clad fibers (DCF) have many advantages in fibered confocal microscopes as they allow for coherent illumination through their core and partially coherent detection through their inner cladding. We report a double-clad fiber coupler (DCFC) made from small inner cladding DCF that preserves optical sectioning in confocal microscopy while increasing collection efficiency and reducing coherent effects. Due to the small inner cladding, previously demonstrated fabrication methods could not be translated to this coupler's fabrication. To make such a coupler possible, we introduce in this article three new design concepts. The resulting DCFC fabricated using two custom fibers and a modified fusion-tapering technique achieves high multimodal extraction (≥70 %) and high single mode transmission (≥80 %). Its application to reflectance confocal microscopy showed a 30-fold increase in detected signal intensity, a 4-fold speckle contrast reduction with a penalty in axial resolution of a factor 2. This coupler paves the way towards more efficient confocal microscopes for clinical applications.