101學年度：藉由行進波消散場與石墨烯飽和吸收體間交互作用所建構之被動鎖模光纖雷射之研究
計畫名稱：藉由行進波消散場與石墨烯飽和吸收體間交互作用所建構之被動鎖模光纖雷射之研究
執行起迄：2012/08/01~2013/10/31
總核定金額：873,000元
中文摘要：超快雷射因具有超短脈衝時間可提供極高之時間與空間解析能力，同時具有寬頻寬及高功率輸出的特性，可應用於超快光譜分析、光學同調斷層掃瞄、光纖通訊和金屬材料奈米加工技術等。而要產生超短脈衝雷射需同時符合諸多條件，首先必須擁有寬頻的增益介質，其次要有脈衝壓縮機制，最後要具有腔內色散補償；其中最為廣泛採用方法是為鎖模技術。在此次的研究計畫中採用被動鎖模方式建構超短脈衝光纖雷射系統，以摻鉺光纖作為雷射增益介質，具有非線性吸收效應之石墨烯飽和吸收體為脈衝壓縮機制，以調整單模光纖長度進行色散補償。選用石墨烯做為飽和吸收體是因其具有超快速之回復時間（~200 fs）以及寬波段的吸收特性能涵蓋整個通訊波段，壓縮機制的方法有別以往行進波直接穿過石墨烯形式，完成側磨光纖（side-polished fiber）的製備後，藉由行進波在纖心纖衣界面存在之消散場（evanescent field）與石墨烯間交互作用來實現，此為本次研究的主軸，探討此方法所建構之雷射輸出表現與光纖側磨的深度對應消散場與石墨烯間耦合強度（coupling strength）對輸出雷射之影響。
英文摘要：Ultrafast lasers often mean that the pulse duration of pulse-lasers is smaller than picoseconds. Their applications include ultrafast spectroscopy, optical coherence tomography (OCT), optical communications (massive WDM or TDM) and laser material processing based on the characteristics of high time resolution, high spatial resolution, high peak intensity and wide bandwidth. To produce an ultra-short pulse laser the cavity must consist of a broadband gain medium, the mechanism for the pulse-compression and the dispersion compensation. In this research the passively mode-locked method will be adopted. An erbium-doped fiber will be used as a gain medium; graphene based saturable absorber will be chose for the pulse-compression due to its strong nonlinearity and fast recovery time (~200 fs); the length of single-mode fibers within the cavity can be adjusted for the dispersion compensation. The interaction scheme of this research between the propagating lightwave and the graphene is different from the past transmission-type (direct) scheme. The side-polished fibers will be first prepared and the graphene will then be placed on the top of the polished side. The pulse-formation will be achieved by the evanescent field interaction. The objective of this research is to evaluate the performance of the mode-locked fiber lasers based on the new interaction scheme and investigate the influence of the polished depth which can be related to the coupling strength between the evanescent wave and the graphene on the mode-locked fiber lasers.
執行起迄：2012/08/01~2013/10/31
總核定金額：873,000元
中文摘要：超快雷射因具有超短脈衝時間可提供極高之時間與空間解析能力，同時具有寬頻寬及高功率輸出的特性，可應用於超快光譜分析、光學同調斷層掃瞄、光纖通訊和金屬材料奈米加工技術等。而要產生超短脈衝雷射需同時符合諸多條件，首先必須擁有寬頻的增益介質，其次要有脈衝壓縮機制，最後要具有腔內色散補償；其中最為廣泛採用方法是為鎖模技術。在此次的研究計畫中採用被動鎖模方式建構超短脈衝光纖雷射系統，以摻鉺光纖作為雷射增益介質，具有非線性吸收效應之石墨烯飽和吸收體為脈衝壓縮機制，以調整單模光纖長度進行色散補償。選用石墨烯做為飽和吸收體是因其具有超快速之回復時間（~200 fs）以及寬波段的吸收特性能涵蓋整個通訊波段，壓縮機制的方法有別以往行進波直接穿過石墨烯形式，完成側磨光纖（side-polished fiber）的製備後，藉由行進波在纖心纖衣界面存在之消散場（evanescent field）與石墨烯間交互作用來實現，此為本次研究的主軸，探討此方法所建構之雷射輸出表現與光纖側磨的深度對應消散場與石墨烯間耦合強度（coupling strength）對輸出雷射之影響。
英文摘要：Ultrafast lasers often mean that the pulse duration of pulse-lasers is smaller than picoseconds. Their applications include ultrafast spectroscopy, optical coherence tomography (OCT), optical communications (massive WDM or TDM) and laser material processing based on the characteristics of high time resolution, high spatial resolution, high peak intensity and wide bandwidth. To produce an ultra-short pulse laser the cavity must consist of a broadband gain medium, the mechanism for the pulse-compression and the dispersion compensation. In this research the passively mode-locked method will be adopted. An erbium-doped fiber will be used as a gain medium; graphene based saturable absorber will be chose for the pulse-compression due to its strong nonlinearity and fast recovery time (~200 fs); the length of single-mode fibers within the cavity can be adjusted for the dispersion compensation. The interaction scheme of this research between the propagating lightwave and the graphene is different from the past transmission-type (direct) scheme. The side-polished fibers will be first prepared and the graphene will then be placed on the top of the polished side. The pulse-formation will be achieved by the evanescent field interaction. The objective of this research is to evaluate the performance of the mode-locked fiber lasers based on the new interaction scheme and investigate the influence of the polished depth which can be related to the coupling strength between the evanescent wave and the graphene on the mode-locked fiber lasers.
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