Supercontinuum generation by higher-order mode excitation in a photonic crystal fiber.
We describe an experiment in which a train of femtosecond pulses is coupled into a photonic crystal fiber (PCF) by means of an offset pumping technique that can selectively excite either the mode LP(01) or LP(11) or LP(21). The PCF presents a wide range of wavelengths in which the fundamental mode experiences normal dispersion, whereas LP(11) and LP(21) propagate in the anomalous dispersion regime, generating a supercontinuum based on the soliton fission mechanism. We find that the existence of a cut-off wavelength for the higher-order modes makes the spectral broadening asymmetrical. This latter effect is particularly dramatic in the case of the LP(21) mode, in which, by using a pump wavelength slightly below cut-off, the spectral broadening occurs only on the blue side of the pump wavelength. Our experimental results are successfully compared to numerical solutions of the nonlinear Schrödinger equation.
Cherif
R
R
Cirta'Com Laboratory, Engineering School of Communication of Tunis (Sup'Com), Ghazala Technopark, 2083, Ariana, Tunisia.
Zghal
M
M
Tartara
L
L
Degiorgio
V
V
D003198:Computer Simulation; D017076:Computer-Aided Design; D003460:Crystallization / Q000379:methods*; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008029:Lighting / Q000379:methods*; D008962:Models, Theoretical; D011789:Quantum Theory