比較傳統與簡化的傳送器用來產生歸零-差分四元相位移鍵/振幅移鍵

Abstract

多重層次的調變如差分四元相位移鍵重新引起注意是因為他可增進頻譜效率在光纖通訊系統上◦ 在這篇論文中我們提供一種簡單而且價格縮減的方式來產生歸零-差分四元相位移鍵/振幅移鍵標籤信號，只需要兩個雙重驅動Mach-Zehnder調變器就可以完成◦首先我們將第一個雙重驅動Mach-Zehnder調變器偏壓位置在Vπ/2及驅動訊號大小Vπ如此可用來取代兩個調變器所產生的歸零-差分四元相位移鍵，再來我們使用混和器來混合正弦波與低速率的標籤信號再將混和後的訊號載入第二個雙重驅動Mach-Zehnder調變器如此可用來取代波形切割器與振幅移鍵調變器◦最後本論文會比較傳統歸零-差分四元相位移鍵/振幅移鍵標籤信號傳送器及簡化歸零-差分四元相位移鍵/振幅移鍵標籤信號傳送器的效能◦

Multilevel modulation signals like differential quadrature phase-shift keying (DQPSK) have received renewed attention to improve the spectral efficiency of a lightwave communication system. In this thesis, we provide a simple and cost effective method to generate DQPSK payload/ASK label signal which only needs two dual-drive Mach-Zehnder modulator (DD-MZM). First, we use bias position (bias=Vπ/2) and drive signal of dual-drive Mach-Zehnder modulator to generated DQPSK signal which replaced two Mach-Zehnder modulator. Second, we also used mixer to mix the sinwave and the low bit rate label data into Mach-Zehnder modulator replace pulse carver and ASK modulator. Finally, the thesis evaluate performance of conventional DQPSK/ASK label transmitter and dual-drive DQPSK/ASK label signal transmitter.