Multiple mode conversion and beam shaping with superimposed long period gratings

Broadband higher order mode conversion using chirped microbend long period gratings.

We suggest a new scheme to create chirped microbend long period gratings. Employing this scheme, the bandwidth of mode conversion between LP01 to LP11 is increased 4.8-fold with a conversion efficiency of 20 dB. This scheme includes a first time demonstration of a non-linearly chirped long period grating. The scheme is investigated both numerically using coupled mode equat...

Long Period Fibre Gratings

A 6-beam Combiner Using Superimposed Volume Index Holographic Gratings

A 6-beam Combiner Using Superimposed Volume Index Holographic Gratings. (August 2004) Ho Nam Yum, B.S., Yonsei University; Chair of Advisory Committee: Dr. Philip Hemmer In this thesis, a 6-beam combiner using multiplexed holograms in dye-doped polymer is investigated. It is realized by recording six superimposed holographic gratings, which show uniform diffraction efficiency. The coupled wave ...

Multiplexed long period gratings with differential interrogation

Long-period gratings in wavelength-scale microfibers.

We report the fabrication of long-period gratings (LPGs) in wavelength-scale microfibers with diameters from 1.5 to 3 microm. The LPGs were fabricated by use of a femtosecond IR laser to periodically modify the surface of the fibers. These LPGs have grating periods of a few tens of micrometers, much smaller than those in conventional optical fibers. A compact 10-period LPG with a device length ...