以半導體雷射放大器做成之光相位共軛器的暫態效應

Abstract

本論文以數值模擬來探討半導體雷射放大器中光相位共軛的暫態效應.半 導體雷射放大器所引進之非對稱形變及瞬時頻率偏移使得相位共軛脈波在 光纖中傳播時, 其波寬會被壓縮得更短, 且在波的前緣會有一些散射波跑 出來. 這些效應, 會隨著半導體雷射放大器入射端的訊號功率增加而變嚴 重. 在模擬時, 我們也包含了放大器的雜訊. 雜訊會影響共軛脈波及此共 軛脈波在光纖中還原的情形. 以上這些效應都可藉由增加唧浦功率而使之 降低.在本文中, 我們也討論了相鄰脈波對光相位共軛訊號的影響. 因為 載子濃度會被前面的脈波所減損, 所以每個共軛脈波的輸出功率會有變 化.在長距離, 多脈波通訊中, 我們用眼形圖來看其波形回復情形. The transient effects of the optical phase conjugation in a semiconductor laser amplifier are studied numerically. The asymmetrical distortion and the additional frequency deviation introduced by semiconductor laser amplifier make the pulse compressed more and induce some dispersive wave in the leading edge of the pulse as the conjugate pulse propagates in the fiber. These effects are enhanced as the signal power increases. The noise of the amplifier is considered. The noise distorts the conjugate pulse and degrades the recovery of the pulse shape. We may reduce these effects by increasing the power of the pump wave. The effects of the neighboring pulses on the generation of the conjugate pulse are also discussed. The output powers of the conjugate pulses fluctuate because the carrier density is depleted by the previous pulses. The eye diagrams are used to show the recovery of the pulse shape in a long distance transmission.