本論文的研究主題為水下無線光通訊系統，主要使用450nm藍光雷射及520nm綠光雷射作為主要光源，然後將1.5m長的玻璃水缸裝滿自來水，並在外側放置雷射光源打進水缸，接著為了在有限的實際空間加長傳輸距離，會在水缸設置鏡面將雷射光來回反射至對面，最後光源會經由對面外側的聚焦透鏡至光偵測器接收。經由這次實驗的傳輸損耗測量，傳輸距離越長功率損耗就越大，且與520nm綠光相比，450nm藍光雷射的接收功率較好，藍光雷射的接收率為綠光雷射接收率的2倍，光損耗率的部分綠光雷射比藍光雷射高1.75倍。為了模擬系統在海水運作時的情形，分別做了溫度變化還有水流擾動的實驗，並且用加入海水素的方式模擬海水。溫度變化的實驗則是以低溫20、22度及高溫30、33度這兩組去做對比，在20度的情況下訊號度接收率是最好的，在33度的時候訊號接收率是最差的，並在30度時接收率有明顯的變化。水流擾動的部分，清水在水流擾動的情況下訊號的接收率干擾幾乎不受影響，海水則是因為參雜了海水素，水中的雜質變多因此訊號接收率也受到很大的影響。關於模擬海水實驗的部分，在距離7.5公尺的傳輸量測實驗下，經由測量結果比較後450nm的藍光雷射與520nm綠光雷射相比，接收效率較高及光損耗較小，藍光雷射的接收率為綠光雷射的接收率的1.7倍，綠光雷射的損耗率為藍光雷射的1.2倍。經過以上實驗的測試，得出水中的雜質密度、傳輸距離還有雷射光頻段會影響到水下光通訊傳輸效率。

The main light source is a 450nm blue laser and a 520nm green laser. A 1.5m long glass tank is filled with tap water and the laser light source is placed on the outside of the tank. The light source will be received by the light detector through the focusing lens on the outside of the opposite side. The longer the transmission distance, the higher the power loss. Compared with the 520nm green light, the 450nm blue laser has a better reception power, and the reception rate of the blue laser is twice as high as that of the green laser. In order to simulate the operation of the system in seawater, experiments on temperature change and water disturbance were conducted, and seawater was simulated by adding seawater elements.The experiment of temperature change is compared with the two groups of low temperature 20, 22 degrees and high temperature 30, 33 degrees, the signal reception rate is the best at 20 degrees, the signal reception rate is the worst at 33 degrees, and the reception rate changes significantly at 30 degrees. In the part of water disturbance, the signal reception of clear water is almost unaffected by the disturbance of water current, while the signal reception of seawater is greatly affected by the impurities in the water due to the inclusion of seawater elements. In the simulated seawater experiment, the 450nm blue laser was measured at a distance of 7.5 meters, and the reception efficiency was higher and the light loss was lower when compared with the 520nm green laser. The reception rate of blue laser is 1.7 times higher than that of green laser, and the loss rate of green laser is 1.2 times higher than that of blue laser. After the above experiments, it is concluded that the impurity density, transmission distance and laser frequency band in water affect the transmission efficiency of underwater optical communication.

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