由於現今網際網路的快速發展，對網路高資料傳輸率的要求亦趨增加。然而目前交換機部分仍仰賴電訊號的處理技術，這限制了網路的透明性 (Transparency)。此外，電交換機處理速度較慢，在光纖通訊網路中形成一大瓶頸。而全光式交換 (all-optical switching)技術可突破電訊號技術限制的瓶頸。全光式封包交換技術最核心的關鍵在於對於訊號的波長轉換 (wavelength conversion)機制。
然而全光式轉換技術大多只能將振幅資訊做轉換，例如XPM、XGM波長轉換技術。而FWM是目前唯一能同時將振幅資訊與相位資訊做轉換的波長轉換技術，因此本篇論文針對傳送不同modulation format與data rate的條件下，利用四波混頻建立全光式封包交換技術的波長轉換機制進行探討。首先介紹各種不同的波長轉換技術，並藉由理論得出FWM適用於不同modulation format之波長轉換系統。接著模擬在傳送QPSK single carrier的條件下，藉由討論改變pump power與高非線性光纖之有效長度找出系統最佳化參數，我們會發現增加pump power與有效長度時，可增加pump與signal之間的FWM非線性效應，因此提高converted signal power，增加performance。但converted signal power太大時，則converted signal 與pump之間作用的FWM會影響原始signal，造成performance下降。因此必須在converted signal power與signal power之間做trade-off。接下來以4-QAM OFDM作為波長轉換之訊號，藉由模擬結果，我們發現DD-OFDM之CSPR為0 dB時，performance最好。Laser linewidth為1 MHz與100 kHz之performance相同，亦即不需特別設計DD-OFDM參數或是使用laser linewidth較窄的laser即可完成波長轉換系統。因此本篇論文中，成功做到訊號透明化之四波混頻全光式波長轉換技術。

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