新類波長可調L-band鎖模光纖雷射

Abstract

在本論文中，我們主要研究與分析長波段的摻鉺光纖放大器和波長可調的摻鉺光纖雷射，並進一步達成波長可調的鎖模雷射。其中，摻鉺光纖放大器的功率轉換效率是37%（較過去有10%的改善），這是嘗試各種不同幫浦架構後最佳化的結果。而波長可調的摻鉺光纖雷射是在不同輸出耦合比下，擁有的內腔損失也不同所造成波長偏移的現象。在輸出耦合比變化的範圍內，產生雷射的位置涵蓋了整個長波段，並且具有相當高的功率和量子效率。此外，我們還在環腔內光纖跳接線連接處產生一微小空隙，如同在環腔內加入一法布里裴洛濾波器，可使得雷射的線寬變的更窄。而波長可調鎖模雷射的部分，是改變不同輸出耦合比使得產生雷射的波長位置偏移，並將其結果和加入可調式濾波器達到波長調變的方法去作比較。最後，根據色散補償的原理，將正啾頻量的輸出脈衝利用單模光纖引入的負啾頻量去達到脈衝壓縮的效果。

In this thesis, we study the L-band erbium-doped fiber amplifier (EDFA) and wavelength-tunable erbium-doped fiber laser (EDFL), and further accomplish mode-locked EDFL. An extremely high power conversion efficiency (PCE) of 37% (10% improvement as compared to that reported using conventional L-band EDFA configuration) in the optimized configuration of EDFA is obtained. In wavelength-tunable EDFL, the wavelength shifting phenomenon results from the different intracavity loss by adjusting the output coupling ratio with a tunable-ratio optical coupler (TROC). In the tuning range, covering the whole L-band, the EDFL has extremely high output power and quantum efficiency. Besides, the lasing linewidth of the EDFL output becomes narrower by simply inserting an tiny air-gap between the FC/PC connectors of fiber patch cord, which functions as a intra-cavity Fabry-Perot filter in the cost-effective L-band EDFL system. Then the wavelength tuning of mode-locked EDFL is achieved by adjusting the output coupling ratio with a TROC which introduces wavelength-dependent cavity loss as well as changing the peak of the gain profile. And we also add tunable band-pass filter in the cavity to attain wavelength-tuning. Finally, according to the dispersion compensation theory, we use single mode fiber with negative group velocity dispersion (GVD) to compress the mode-locked EDFL output with positively chirped pulse.