本論文運用串接式單載子傳輸光偵測器提升射頻光纖系統中接收端前級元件光二極體的飽和電流與頻寬乘積值，而這個乘積值往往成為判斷元件好壞程度的重要參數。經由理論得知飽和電流和頻寬受元件收光面積與空乏區厚度影響；薄的空乏區厚度造成電容上升，但會使得載子傳輸時間下降得到高輸出飽和電流，故必須降低主動區面積使得電容值下降，藉以得到高頻寬表現。因此本文內容將探討利用串接式結構提升飽和電流與頻寬乘積值，令元件能夠承受更高飽和電流(75mA)，且頻寬也可以維持在100GHz，在50歐姆負載下擁有創新紀錄的飽和電流與頻寬之乘積(7500mA-GHz, 75mA, 100GHz)。In this study, we demonstrate linear-cascade near-ballistic uni-traveling carrier photodiodes (LCPDs) with an optimized extremely high saturation current-bandwidth product performance (7500mA-GHz, 75mA, 100GHz,) which is the key parameter of photodiode with radio-of-fiber communication system. A thinner depletion layer thickness indicates a larger junction capacitance, a shorter carrier transit time, and a higher saturation current performance. The downscaling of device active area is thus necessary to sustain a low junction capacitance and achieve very-high speed performance. In this work we demonstrate linear cascade near-ballistic uni-traveling-carrier photodiodes. Compared with control (a single device), this novel structure exhibits significant improvement in bandwidth-efficiency and saturation-current-bandwidth products. Record-high saturation-current-bandwidth product (>7500mA-GHz, 100GHz) under 50? loads can be achieved.
