Title :
Transverse modes under external feedback and fiber coupling efficiencies of VCSEL´s
Author :
Heinrich, J. ; Zeeb, H. ; Ebeling, K.J.
Author_Institution :
Res. Center, Daimler-Benz AG, Ulm, Germany
Abstract :
We report a detailed study on the transverse mode behavior of vertical-cavity surface-emitting lasers (VCSEL´s) under strong external feedback. Backreflections from a glass facet result, periodically depending on the feedback phase, in variations of the transverse mode pattern of strongly index guided multitransverse-mode-emitting lasers. As a result, butt-coupling efficiencies of these lasers strongly depend on laser-fiber distance. For typical active VCSEL diameters around 15-μm fiber-coupled powers into standard 50 μm-core diameter graded-index (GI) silica fibers vary by nearly 10 dB. Even for high-numerical aperture 100-μm-core diameter fibers, power variations of up to 2 dB are observed.
Keywords :
gradient index optics; laser cavity resonators; laser feedback; laser modes; light reflection; optical fibre communication; optical fibre couplers; refractive index; semiconductor lasers; surface emitting lasers; 100 mum; 15 mum; 50 mum; VCSEL; VCSEL´s; active VCSEL diameters; backreflections; butt-coupling efficiencies; external feedback; feedback phase; fiber coupling efficiencies; fiber-coupled powers; glass facet; graded-index silica fibers; high-numerical aperture; laser-fiber distance; power variations; strong external feedback; strongly index guided multitransverse-mode-emitting lasers; transverse mode behavior; transverse mode pattern; transverse modes; vertical-cavity surface-emitting lasers; Fiber lasers; Laser feedback; Laser modes; Optical coupling; Optical feedback; Optical fibers; Optical interconnections; Optical surface waves; Surface emitting lasers; Vertical cavity surface emitting lasers;
Journal_Title :
Photonics Technology Letters, IEEE
