Hannover 2016 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 4: Photonics I
Q 4.2: Talk
Monday, February 29, 2016, 11:15–11:30, f342
Ultrafast all-optical mode conversion in graded-index fibers — •Martin Schnack, Tim Hellwig, and Carsten Fallnich — Institute of Applied Physics, University of Münster, Corrensstraße 2, 48149 Münster
We present experimental results on all-optical transverse mode conversion in graded-index multi-mode fibers. Ultrashort probe pulses are converted from the fundamental mode to the next higher-order modes by optically induced transient long-period gratings1. Temporally synchronized, high-power subpicosecond control pulses are used to excite a combination of transverse modes in the fiber. By exploiting the Kerr-effect the periodic spatial intensity pattern emerging from multi-mode interference is translated into a spatial refractive index modulation, transiently inducing the necessary long period grating.
The graded refractive index profile of the fiber allows for the first time to achieve efficient mode conversion using control and probe pulses at separate wavelengths2. The probe pulses are thus easily distinguishable by spectral filtering and can be directly visualized. Furthermore, numerical simulations are presented, exhibiting excellent agreement with the experimental results.
1 Walbaum T., Fallnich C., Appl. Phys. B 115, 225 (2014)
2 Schnack M., et. al., Opt. Lett. 40, 4675 (2015)