Mode mixing and polarization scrambling microparticles in polymeric resin filled optical couplers

Abstract

The fiber-to-fiber uniformity, optical loss, and size of polymeric multimode combiners and splitters was enhanced by the addition of mode mixing microspheres when low numerical aperture (NA) sources were used. Mixing rod type resin filled polymeric optical couplers could be significantly shortened when used with small beam divergence angle lasers and other small NA sources. The small NA beam divergence angle causes the energy to remain in low-order modes for desired mixing lengths, causing fiber-to-fiber nonuniformity. A solution to this problem a mode mixing refractive microsphere technology, is presented. Results demonstrate that the use of the microspheres improved the performance of both optical splitters and combiners. Silica microparticles were suspended in the polymer mixing regions of the couplers. The shortened mixing lengths accomplished with the microparticles also makes it possible to use polymeric couplers with longer wavelengths of light where polymers are not as transparent. >