全正色散摻鐿飛秒光纖雷射

Abstract

本論文實驗中我們利用偏振疊加波來實現被動鎖模，並成功地發展出一組鎖模摻鐿光纖雷射振盪器，在泵浦功率280 mW下輸出一中心波長落在1064 nm、重複率約14.68MHz、平均輸出功率4.8mW、脈衝寬度約24.6 ps的脈衝序列。本實驗的雷射共振腔為全單模光纖系統，在此系統下鎖模雷射預期遭遇脈衝寬度因材料色散使得脈衝寬度展寬的情形，我們將採用腔外色散補償的方式來改善並獲得飛秒等級的超快雷射。另外，我們在實驗架構中藉由改變共振腔的長度，更換三種不同分光比例的光耦合器來比較輸出之雷射特性，並觀察到當共振腔長度越短，輸入於共振腔內的光越強時，輸出的脈衝寬度將會越窄。最後我們將雷射種子源連結至一前級放大器並使用光柵對進行脈衝壓縮。最終獲得540飛秒的超快脈衝雷射輸出。我們希望能藉此研究實現開機即可鎖模、低成本、易操作的皮秒種子雷射光源。此光源可進一步結合高功率摻鐿光纖放大器，產生高能量的皮秒超短脈衝雷射，在藉由腔外色散補償結構產生飛秒等級的超快脈衝雷射。由於光纖雷射具有許多優點，例如可小型積體化、成本較低廉、高轉換效率、低散熱需求、無須光學對準、長時間穩定且在高功率輸出下仍可保持良好之光束品質等等，故本研究將有助於提升國內光纖雷射相關廠商的研發能量。

In this research, we use the polarization additive pulse mode-lock (PAPM) to achieve passive mode-locking and successfully manufacture a mode-locked ytterbium-doped fiber (YDF) oscillator. When the launched pump power is 280 mW, the properties of the output laser are：center wavelength 1064 nm、14.68MHz repetition rate、average output power 4.8 mW and 24.6 ps pulse width. All single-mode fiber laser system is present in this research , this system is expected to encounter material dispersion that would induce the phenomenon of pulse spread. We use dispersion compensation out of the oscillator to get the femto-second pulse laser. In addition, we change the length of cavity and couplers with different splitting ratio to compare the characteristics of the output laser. We find the pulse width will be narrower as long as the shorter length of cavity and greater light injected into the cavity. Finally, we use a pre-amplifier to balance the loss of the grating pair and get 540 femto-second laser output. With the performing of this research, we hope our results could be helpful for the development of the domestic manufacturers of fiber lasers and related photonic industrials.