Multiple mode conversion and beam shaping with superimposed long period gratings.
We demonstrate how to convert several arbitrary optical fiber modes into a single mode and vice versa using superimposed long period gratings (SLPG). As an example, we theoretically consider SLPG consisting of five gratings, which couple first six LP(0j) modes of a single mode fiber. We optimize the SLPG output to form light beams that are focused at a distance 0.5 mm and 1 mm from the fiber. In addition, we optimize the SLPG output to generate a beam with an amplitude that is uniform inside a 4(0) angle with a +/-0.2 % accuracy. In the latter case, the refractive index profile of the SLPG is calculated for an SMF-28 fiber. The proposed SLPG devices can be used as efficient all-fiber mode focusers and beam shapers.
Sumetsky
M
M
OFS Laboratories, 19 Schoolhouse Road, Somerset, NJ 08873, USA. sumetski@ofsoptics.com
Ramachandran
S
S
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation* / Q000379:methods*; D008962:Models, Theoretical; D055100:Optical Fibers; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods*; D012542:Scattering, Radiation