基于线性光放大器的全光逻辑异或门理论分析

基于速率方程建立了线性光放大器(LOA)的数值模型,模拟了线性光放大器的增益钳制特性。与对称结构马赫曾德尔干涉仪(MZI)的传输矩阵相结合,构建了线性光放大器马赫曾德尔干涉仪全光逻辑异或门模型,实现了两路40Gbit/s信号的异或运算。与传统的半导体光放大器(SOA)构成的马赫曾德尔干涉仪型异或门进行了比较,从器件结构上对两种异或门运算结果的差异给出了解释。结果表明,线性光放大器具有平坦的增益特性,对输入信号的扰动具有不敏感性,垂直光场缩短了载流子恢复时间;线性光放大器马赫曾德尔干涉仪结构可以实现异或运算;利用差分相位法可以解决载流子恢复时间对信号处理速度的限制,合理地选择延迟时间能获得较好的运算结果;输出信号具有眼图张开度大、消光比高、峰值啁啾小、对波长变化不敏感等优点。

Theoretical Analysis on All-Optical XOR Using Linear Optical Amplifier

The numerical model of the linear optical amplifier(LOA) is built based on the rate equations.The gain clamping characteristics of LOA are simulated.By combining the transmission matrix of the symmetrical,Mach-Zehnder interferometer(MZI),the all-optical XOR model of LOA-MZI has been constracted,and two XOR operations are realized at 40 Gbit/s.The performance of the XOR result has been analyzed and compared with the semiconductor optical amplifier(SOA)-MZI.The result differences of the two XOR gates are explained from the structural property.The theoretical results indicate that,LOA has a flat gain characteristic and improved tolerance against small signal distortions,the carrier recovery time is shorted by the vertical laser field,and all-optical XOR functionality can been achieved by using LOA-MZI.By using the differential phase scheme the high-speed operation limitation by the carrier recovery time is solved,and better results can be achieved by choosing the delay time properly.The output signals of LOA-MZI have opener eye diagram,higher extinction ratio,lower peak chirp and lower sensitivity to wavelength.