Multiple approaches to generate a smooth, powerful, and stable supercontinuum in cobweb photonic-crystal fibers were undertaken by use of 18-fs pulses. These approaches include utilization of incident pulses with various chirp, power, and polarization states, as well as fibers with different lengths and core sizes. For long fibers (tens of centimeters) the supercontinuum contains a finely modulated structure that can be smoothed when the oscillator is in a regime of relaxation oscillations. Short fibers provide a supercontinuum free of gaps. By optimization of these parameters supercontinua exceeding one octave with modulations of less than 10 dB have been generated.
© 2002 Optical Society of America
(060.2310) Fiber optics and optical communications : Fiber optics
(170.4500) Medical optics and biotechnology : Optical coherence tomography
(320.7140) Ultrafast optics : Ultrafast processes in fibers
Alexander Apolonski, Boris Povazay, Angelika Unterhuber, Wolfgang Drexler, William J. Wadsworth, Jonathan C. Knight, and Phillip St. J. Russell, "Spectral shaping of supercontinuum in a cobweb photonic-crystal fiber with sub-20-fs pulses," J. Opt. Soc. Am. B 19, 2165-2170 (2002)