基于晶体延迟干涉仪的20-Gb/sNRZ-DQPSK解调实验研究

Experimental study of 20 Gb/s optical NRZDQPSK demodulation based on crystal delay-line interferometer

光差分四相移键控(DQPSK)信号解调技术是相位调制光纤通信系统中的关键技术,本文利用钒酸钇(YVO4)晶体设计制作了2 bit延迟干涉仪(DI)作为DQPSK解调器。相对于传统的基于光纤结构的DI,用晶体材料制作的DI具有温度稳定性高的特点,其作为光DQPSK解调技术中的关键器件,具有广泛的应用前景。实验搭建了20 Gb/s光NRZ-DQPSK背靠背实验系统,并利用自主设计制作的DI成功实现了NRZ-DQPSK信号解调。实验结果与计算机仿真计算结果一致。

Optical differential quadrature phase shift keying（DQPSK） signal demodulation is one of the key technologies to accomplish a phase-modulated optical fiber communication system.In this paper,we design and setup a 2-bit delay interferometer（DI） utilizing YVO4 crystals,which is used as a DQPSK signal demodulator.Compared with the traditional DI usually based on fibers,the crystal based DI gains an advantage of higher temperature stability,which therefore will have a broad prospect in application as a key device capable of optical DQPSK demodulating.We set up a 20 Gb/s optical NRZ-DQPSK back-to-back system,which achieve great success in demodulation of NRZ-DQPSK signal.The experimental results well agree with the simulation results calculated by computers.