tailieunhanh - Coherence and Ultrashort Pulse Laser Emission Part 13

Tham khảo tài liệu 'coherence and ultrashort pulse laser emission part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 472 Coherence and Ultrashort Pulse Laser Emission at longer wavelengths. Hence the modulation of the signal pulse at longer wavelengths and of the fundamental pulse at shorter wavelengths is depressed. Then the larger gap between the fundamental and signal spectra is formed. In contrast when the two pulses meet at the end of the fiber Td -80 fs the trailing edge longer wavelengths of the signal pulse mainly interacts with the leading edge shorter wavelengths of the fundamental pulse. As a result the IPM-induced spectrum of the signal pulse shifts towards its longer wavelengths and the IPM-induced fundamental pulse spectrum shifts towards its shorter wavelengths and a larger overlap of the two pulse spectra is observed in both Figs. 13 c and 14 c . This shows that the calculation qualitatively agrees well with the previous experimental results. The spectral bandwidth of Fig. 13 c is Iz1 100i zmax-zmin - nm. The spectral bandwidth of Fig. 14 c is lz1 100i zmxx-zmin - nm. It is found that when the two pulses meet at the center of the fiber the fundamental pulse passes through the signal pulse in a symmetric manner. As a result the spectra are broadened by the IPM effect to shorter and longer wavelengths simultaneously for both pulses and the broadest combined spectrum is generated in both Figs. 13 b and 14 b . This shows that the calculation qualitatively agrees well with the previous experimental results. The spectral bandwidth of Fig. 13 b is lz1 10i0 zmxx-zmin - nm. The spectral bandwidth of Fig. 14 b is lz1 100 zmxx-zmin - nm. Figures 13 b and 14 b generally have the same value of I1 100. This case is referred to as the optimum initial time delay to produce the broadest spectrum. In Figs. 13 and 14 it is the same feature that the most broadened spectra are Fig. 13 b and Fig. 14 b with an initial delay of Td -40 fs. Consequently the extended FDTD results and our previous experimental results .