SEDI-ATI Fibres Optiques has produced for many years multimode fiber optic coupler/dividers based on a proprietary technology.
The two port fibers are polished laterally up to half of their diameter and then assembled and spliced to the common fiber.
This technology offers several interesting characteristics compared to standard fused couplers :
• Coupling ratio not affected by wavelength variation.
• Very low sensitivity to modal conditions.
• Possibility to couple or divide large core step index fibers as well as graded index fibers.
However in this first construction the fibers inside are assembled with adhesive and this process is not adapted to high power operation.
In 2012 an important R&D program was launched by SEDI-ATI to find a solution to this problem.
The idea was to fuse the polished fibers together instead of gluing them.
Maintaining a perfect geometry during the fusion process was a difficult challenge but the first results obtained are above expectation.