高消光比双通马赫-曾德尔干涉仪梳状滤波器

提出了一种新颖结构的高消光比双通马赫-曾德尔干涉仪梳状滤波器，将常规单通马赫-曾德尔干涉仪的两个输出端与光隔离器连接，构成一个双通马赫-曾德尔干涉仪梳妆滤波器，对滤波器的输出特性进行了理论分析和实验研究。数值模拟表明，与常规的单通马赫-曾德尔干涉仪相比，在相同参量的情况下该双通马赫-曾德尔干涉仪梳妆滤器的消光比得到了大大改善，消光比的提高取决于干涉仪的臂长差，当干涉仪的臂长差为0．7366mm时，消光比提高了20dB。实验结果表明，双通马赫-曾德尔干涉仪梳妆滤器的消光比为25．8dB，消光比提高了13dB。

High Extinction Ratio Comb Filters Based on Dual-Pass Mach-Zehnder Interferometer

A novel structure of high extinction ratio comb filter based on dual-pass Mach-Zehnder interferometer is proposed. The comb filter is structured by adding an optical isolator to the two outputs of the conventional single-pass Mach-Zehnder interferometer. The characteristic of the transmission spectrum is studied theoretically and experimentally. The numerical results show that the extinction ratio can be enhanced greatly in comparison with the conventional single-pass Mach-Zehnder interferometer in the same parameters. The improvement of the extinction ratio mainly depends on the difference between the two arms of the Mach-Zehnder interferometer. When the difference is 0.7366 mm, the extinction ratio is improved 20 dB. The experimental results show that the extinction ratio of the dual-pass Mach-Zehnder interferometer is 25.8 dB,the extinction ratio is improvedly 13 dB.