全光纖式被動Q開關脈衝雷射之研究

Study of All Fiber Passively Q-Switched Pulses Laser

范信安(Shin-An Fan)

指導教授 ： 何淳雪

中原大學/理學院/應用物理研究所/碩士(2007年)

https://doi.org/10.6840/cycu200700405

摘要

全光纖式被動Q開關雷射在特性上有高功率，高效率，壽命長，體積小和靈活小巧的優點，所以在應用方面相當有潛力。本文利用波長為976nm之二極體雷射、掺釤光纖、布拉格光纖光柵和摻鐿雙纖殼光纖組成全光纖式被動Q開關雷射，其脈衝雷射的中心波長為1086.44nm，頻寬為1nm，脈衝能量為202nJ，脈衝週期為20.2μs，脈衝頻率為50kHz，脈衝寬度為0.9μs，峰值功率為224.4mW。
在全光纖式被動Q開關雷射的實驗架構中，我們利用摻釤光纖做為架構中的飽和吸收體，再改變摻釤光纖不同位置和不同長度，量測其平均功率與脈衝週期之改變。當摻釤光纖置放於共振腔後端時比其置放於共振腔前端時，可獲得較大的平均功率和較短的脈衝週期。隨著摻釤光纖長度的增加，其平均功率將變小，脈衝週期變大。
我們也量測泵浦光源功率的變化，對全光纖式被動Q開關雷射的輸出功率、脈衝週期與脈衝能量的影響。我們所得的結論為，當泵浦功率越來越大時，輸出功率越大，脈衝週期越小，脈衝能量越大。

關鍵字

飽和吸收體 ； Q開關 ； 脈衝雷射

並列摘要

An all-fiber passive Q-switched pulsed laser has been established and its performance has been investigated. The laser system was configured by using a Samarium (Sm)-doped fiber as saturable absorber, a Yb3+-doped double cladding fiber as the gain medium, and a Bragg-fiber gratings as the optical cavity.
In the past, most of the Q-switched fiber lasers are consist of bulky elements that normally invoke sophisticated designs and are usually drawback by incompactness. Here, the conventional crystal saturable absorber was replaced by a Sm-doped fiber, making this pulsed laser as a genuine all-fiber Q-switched laser. In addition, a Yb3+-doped double cladding fiber was also adopted in the system to improve its coupling efficiency and output power. In the preliminary test, a pulse energy of 202 nJ, repetition rate of 50 kHz have been shown. The present optimized results, the pulse width of 0.9μs, and with a peak power of 224.4 mW at center wavelength of 1086.44 nm and a FWHM bandwidth of 1 nm were achieved.
The effects of pumping optical source power on the output power, repetition rate, and pulse energy were also investigated. It was found that the higher the pumping power, the higher the output power and pulse energy, but the lower the repetition rate.

並列關鍵字

Q-switched ； pulse laser ； saturable absorber

參考文獻

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