Wavelength Tunable And Pulsewidth Stretchable Femtosecond Mode-Locked Fiber Laser Based On Dispersion Engineering Technique

• Main Authors: Liu, Feng Chou, 劉鳳洲
• Other Authors: Chen, Nan Kuang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/39512159287043572743

碩士 === 國立聯合大學 === 光電工程學系碩士班 === 100 === We demonstrate a pulsewidth tuning and wavelength-tunable femtosecond mode-locked fiber laser by using an intracavity short-pass edge filter. When the filter is thermo-optically tuned to overlap the constituting spectral components of mode-locked pulses, large negative waveguide dispersion is introduced by the steep cutoff slope and the total cavity dispersion is moved to normal dispersion regime to broaden the pulsewidth. Pulse stretch ratio of 3.53 (623.8fs/176.8fs) can be efficiently achieved under a temperature variation of 4ºC or tuned toward shorter wavelengths to strongly attenuate the wavelengths longer than the cutoff, the constituting wavelengths of the mode-locked fiber laser move to shorter wavelengths and the laser center wavelength can be tuned over 1539.7~1560 nm The cavity dispersion get fast switching between the anomalous dispersion regime or normal dispersion to highly efficient pulse stretchable stretching or keep small fluctuations of laser pulsewidth when the laser wavelength is tuned.