Nonlinear Fiber Optics - 4 ed. Agrawal

482 Chapter 12. Novel Nonlinear Phenomena
Figure 12.23: (a) Recorded spectra at the output of a 5-m-long fiber for 8 average power levels
of 100-fs input pulses. (After Ref. [104]; c○2002 OSA.)
Figure 12.24 presents a more graphical view of the power-dependence of the fission
process that is responsible for the creation of multiple fundamental solitons whose
spectra shift rapidly toward longer wavelengths [112]. In this experiment, 110-fs pulses
with a 80-MHz repetition rate at a wavelength of 1550 nm were launched into a 2.6-
μm core photonic crystal fiber made of lead-silicate glass (Schott SF6) with a value of
n 2 that is 10 times larger than that of silica. The experiment was repeated for average
launched powers in the range of 0 to 70 mW. Figure 12.24 shows the recorded spectra
such that the gray scale represents variations in the optical power with wavelength.
The fiber length is only 5.7 mm in the image (a) and increases to 70 cm for the image
(b). In the case of a long fiber, fundamental solitons with RIFS form for P av values as
low as 1 mW, and their number and the magnitude of RIFS increase with an increase
in P av . The fiber length in (a) is so much shorter than the dispersion length (about
Figure 12.24: Recorded spectra as a function of average power at the output of a microstructured
fiber when 110-fs pulses are propagated over a fiber length of (a) 0.57 and (b) 70 cm. Arrows
indicate solitons created after the fission. (After Ref. [112]; c○2006 OSA.)