We propose mode division multiplex communication technique that can split a specific spatial mode in light from a spatial mode multiplexed in an optical fiber by fusion of a phase conjugation technique with spatial filtering processing by multiplexed volume holograms and random diffusers. In mode division multiplexing, the optical signal outgoing from the multimode optical fiber is in a condition that optical information of plural spatial modes is overlapped, therefore it is difficult to de-multiplex electrically after light detection. Our technique enables to split it into each mode all optically and to compensate temporal modal shift dynamically. Mode de-multiplexing is realized by multiplexed holographic arithmetic device and phase matching of a wave surface for the spatial mode orthogonal to time. Therefore, if we use indices in conventional electronic processing, a very high-speed operation equivalent to that of 10-100PFLOPS can be realized without causing any delay in light information to be transmitted. Moreover, it can realize constructions of a system that can dynamically respond to temporal mode variations and distortions with fiber transmissions by using a photorefractive medium. Separating of around 60-70% was achieved in an experiment of separating three multiplexed spatial modes by controlling a volume type dynamic reconfigurable device based on LiNbO₃. It was clarified that the separation performance improved by an appropriate random phase mask in the numerical analysis.

Date Published: 13 May 2010
PDF: 10 pages
Proc. SPIE 7716, Micro-Optics 2010, 771627 (13 May 2010); doi: 10.1117/12.854106

Published in SPIE Proceedings Vol. 7716:
Micro-Optics 2010
Hugo Thienpont; Peter Van Daele; Jürgen Mohr; Hans Zappe, Editor(s)