- 學位論文
腔內梳狀濾波高重複率鎖模摻鉺光纖雷射之研究
Study of high repetition rate mode locked Er doped fiber lasers with intra cavity comb filtering
摘要
本論文中，我們成功地實現了重複率高達 100 GHz 和 250 GHz 的脈衝雷射，透過 sigma 型式的雷射腔體，使得光得以保持單一偏振態，從而得到極度穩定的 100 GHz 脈衝序列，更進一步透過簡單的 回授控制，使得長期的雷射輸出功率變動值可以降低至 0.1 % 左右。而另一個 250 GHz的鎖模雷射則使用了高功率的摻鉺光纖放大器作為泵浦 並且使用矽環形共振器 來濾波，透過外部注入一個窄頻寬的 連續式雷射，可以有效的壓制超模所造成的擾動，進而大幅的提升自相關儀所量測到的脈衝 對比度。在這兩個不同架構的雷射中都使用了好幾百公尺的高非線性光纖來提供充足的非線性效應，像是自相位調變和四波混頻等。透過光譜儀、自相關儀和射頻頻譜儀等設備的使用，我們詳細探討了這兩種雷射的重要特性。
並列摘要
In the thesis work two high repetition rate fiber lasers up to 100 GHz and 250 GHz are successfully demonstrated. By utilizing a sigma type laser cavity, a highly stable 100 GHz fiber laser is achieved, thanks to the polarization maintaining cavity design. Moreover, through a simple feedback control loop, the long term output power variation is lowered to the level of 0.1 %. Another 250 GHz mode-locking laser is pumped by a high power EDFA and filtered through a silicon-microring resonator in the cavity. The autocorrelation trace is significantly improved by injecting a narrow bandwidth CW laser, which is capable of suppressing the super-mode noises. Both laser schemes require a section of several hundred meters of high nonlinearity fiber to provide the sufficient nonlinear effects of self-phase modulation and four-wave mixing. The characteristics of both laser are investigated in details by the measurement of optical spectrum, autocorrelation trace and RF spectrum.