Femtosecond Soliton-Effect Compression of Backward-Optical-Injection Mode-Locked Semiconductor Optical Amplifier Fiber Lasers

• Main Authors: I-Hsiang Chiu, 邱奕祥
• Other Authors: Gong-Ru Lin
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/40428810444363306026

碩士 === 國立交通大學 === 光電工程系所 === 93 === In this thesis, we study the harmonic mode-locking dynamics of a backward optical injection modulated SOAFL. The effects of gain-depletion time and modulation frequency on the mode-locked pulse shape and power have also been theoretically analyzed and experimentally demonstrated. The backward sinusoidal-wave modulation is much easier to initiate harmonic mode-locking in SOAFL than the gain-switched modulation, which generates pulsewidth as short as 5.4 ps at 10 GHz. The difficulty in mode-locking the SOAFL by optical short pulse injection is also demonstrated and explained, which is attributed to the insufficient gain-depletion time (as well as modulation depth). In the linear pulse compression, the negative high dispersion fiber compensates negative chirped pulse. Furthermore, the nonlinear pulse compression uses a piece of optimum fiber length to compress linear pulse compression. It employs SPM and GVD interplay in a fiber. It also needs a high peak power to generate nonlinear effect. But the pulse has a large pedestal. Finally, we use the intensity discriminator to remove pedestal. It uses the intensity dependent birefringence effect in optical fibers and to realize pedestal free nonlinear compressed pulse. The pulse width is equal to nonlinear pulse compression pulse.