Optically induced long-period fiber gratings for guided mode conversion in few-mode fibers.
We propose and demonstrate guided mode conversion by an optically induced long-period fiber grating (OLPG). The beating of two guided modes excited by a nanosecond pulsed laser beam is used to induce a refractive index grating via the Kerr effect. This grating converts a counter-propagating continuous-wave beam from the LP(01) to the LP(11) mode. Numerical simulations using a beam propagation method show that a full conversion is possible. Experimentally, a mode conversion with an efficiency of about 50% is firstly demonstrated.
Andermahr
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Laser Zentrum Hannover, Hollerithallee 8, 30419 Hannover, Germany. andermahr@uni-muenster.de
Fallnich
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