Experimental realization of femtosecond transverse mode conversion using optically induced transient long-period gratings.
We present the experimental realization of transverse mode conversion in an optical fiber via an optically induced long-period grating. The transient gratings are generated by femtosecond laser pulses, exploiting the Kerr effect to translate intensity patterns emerging from multimode interference into a spatial refractive index modulation. Since these modulations exist only while the pump beam is present, they can be used for optical switching of transverse modes. As only a localized part of the grating was written at a time and the probe beam was co-propagating with the pump beam the required pulse energies could be reduced to 120 nJ which is about a factor of 600 lower than in previous quasi-continuous-wave experiments. Accompanying numerical simulations allow a better understanding of the involved effects and show excellent agreement to the experimental results.
Tim
T
Hellwig
Martin
M
Schnack
Till
T
Walbaum
Sven
S
Dobner
Carsten
C
Fallnich
D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D012399:Rotation; D013997:Time Factors